Compiler reference guide

Applies to Linux and Windows

2024-01-16

98 min read time

Introduction to compiler reference guide

ROCmCC is a Clang/LLVM-based compiler. It is optimized for high-performance computing on AMD GPUs and CPUs and supports various heterogeneous programming models such as HIP, OpenMP, and OpenCL.

ROCmCC is made available via two packages: rocm-llvm and rocm-llvm-alt. The differences are listed in the table below.

Differences between rocm-llvm and rocm-llvm-alt

rocm-llvm	rocm-llvm-alt
Installed by default when ROCm™ itself is installed	An optional package
Provides an open-source compiler	Provides an additional closed-source compiler for users interested in additional CPU optimizations not available in rocm-llvm

For more details, see:

• AMD GPU usage: llvm.org/docs/AMDGPUUsage.html

• Releases and source: RadeonOpenCompute/llvm-project

ROCm compiler interfaces

ROCm currently provides two compiler interfaces for compiling HIP programs:

• /opt/rocm/bin/hipcc

• /opt/rocm/bin/amdclang++

Both leverage the same LLVM compiler technology with the AMD GCN GPU support; however, they offer a slightly different user experience. The hipcc command-line interface aims to provide a more familiar user interface to users who are experienced in CUDA but relatively new to the ROCm/HIP development environment. On the other hand, amdclang++ provides a user interface identical to the clang++ compiler. It is more suitable for experienced developers who want to directly interact with the clang compiler and gain full control of their application’s build process.

The major differences between hipcc and amdclang++ are listed below:

Differences between hipcc and amdclang++

*	hipcc	amdclang++
Compiling HIP source files	Treats all source files as HIP language source files	Enables the HIP language support for files with the .hip extension or through the -x hip compiler option
Detecting GPU architecture	Auto-detects the GPUs available on the system and generates code for those devices when no GPU architecture is specified	Has AMD GCN gfx803 as the default GPU architecture. The --offload-arch compiler option may be used to target other GPU architectures
Finding a HIP installation	Finds the HIP installation based on its own location and its knowledge about the ROCm directory structure	First looks for HIP under the same parent directory as its own LLVM directory and then falls back on /opt/rocm. Users can use the --rocm-path option to instruct the compiler to use HIP from the specified ROCm installation.
Linking to the HIP runtime library	Is configured to automatically link to the HIP runtime from the detected HIP installation	Requires the --hip-link flag to be specified to link to the HIP runtime. Alternatively, users can use the -l<dir> -lamdhip64 option to link to a HIP runtime library.
Device function inlining	Inlines all GPU device functions, which provide greater performance and compatibility for codes that contain file scoped or device function scoped __shared__ variables. However, it may increase compile time.	Relies on inlining heuristics to control inlining. Users experiencing performance or compilation issues with code using file scoped or device function scoped __shared__ variables could try -mllvm -amdgpu-early-inline-all=true -mllvm -amdgpu-function-calls=false to work around the issue. There are plans to address these issues with future compiler improvements.
Source code location	ROCm-Developer-Tools/HIPCC	RadeonOpenCompute/llvm-project

Compiler options and features

This chapter discusses compiler options and features.

AMD GPU compilation

This section outlines commonly used compiler flags for hipcc and amdclang++.

-x hip

Compiles the source file as a HIP program.

-fopenmp

Enables the OpenMP support.

-fopenmp-targets=<gpu>

Enables the OpenMP target offload support of the specified GPU architecture.

Gpu:

The GPU architecture. E.g. gfx908.

--gpu-max-threads-per-block=<value>:

Sets the default limit of threads per block. Also referred to as the launch bounds.

Value:

The default maximum amount of threads per block.

-munsafe-fp-atomics

Enables unsafe floating point atomic instructions (AMDGPU only).

-ffast-math

Allows aggressive, lossy floating-point optimizations.

-mwavefrontsize64, -mno-wavefrontsize64

Sets wavefront size to be 64 or 32 on RDNA architectures.

-mcumode

Switches between CU and WGP modes on RDNA architectures.

--offload-arch=<gpu>

HIP offloading target ID. May be specified more than once.

Gpu:

The a device architecture followed by target ID features delimited by a colon. Each target ID feature is a predefined string followed by a plus or minus sign (e.g. gfx908:xnack+:sramecc-).

-g

Generates source-level debug information.

-fgpu-rdc, -fno-gpu-rdc

Generates relocatable device code, also known as separate compilation mode.

AMD optimizations for zen architectures

The CPU compiler optimizations described in this chapter originate from the AMD Optimizing C/C++ Compiler (AOCC) compiler. They are available in ROCmCC if the optional rocm-llvm-alt package is installed. The user’s interaction with the compiler does not change once rocm-llvm-alt is installed. The user should use the same compiler entry point, provided AMD provides high-performance compiler optimizations for Zen-based processors in AOCC.

For more information, refer to https://www.amd.com/en/developer/aocc.html.

-famd-opt

Enables a default set of AMD proprietary optimizations for the AMD Zen CPU architectures.

-fno-amd-opt disables the AMD proprietary optimizations.

The -famd-opt flag is useful when a user wants to build with the proprietary optimization compiler and not have to depend on setting any of the other proprietary optimization flags.

Note

-famd-opt can be used in addition to the other proprietary CPU optimization flags. The table of optimizations below implicitly enables the invocation of the AMD proprietary optimizations compiler, whereas the -famd-opt flag requires this to be handled explicitly.

-fstruct-layout=[1,2,3,4,5,6,7]

Analyzes the whole program to determine if the structures in the code can be peeled and the pointer or integer fields in the structure can be compressed. If feasible, this optimization transforms the code to enable these improvements. This transformation is likely to improve cache utilization and memory bandwidth. It is expected to improve the scalability of programs executed on multiple cores.

This is effective only under -flto, as the whole program analysis is required to perform this optimization. Users can choose different levels of aggressiveness with which this optimization can be applied to the application, with 1 being the least aggressive and 7 being the most aggressive level.

-fstruct-layout Values and Their Effects

-fstruct-layout value	Structure peeling	Pointer size after selective compression of self-referential pointers in structures, wherever safe	Type of structure fields eligible for compression	Whether compression performed under safety check
1	Enabled	NA	NA	NA
2	Enabled	32-bit	NA	NA
3	Enabled	16-bit	NA	NA
4	Enabled	32-bit	Integer	Yes
5	Enabled	16-bit	Integer	Yes
6	Enabled	32-bit	64-bit signed int or unsigned int. Users must ensure that the values assigned to 64-bit signed int fields are in range -(2^31 - 1) to +(2^31 - 1) and 64-bit unsigned int fields are in the range 0 to +(2^31 - 1). Otherwise, you may obtain incorrect results.	No. Users must ensure the safety based on the program compiled.
7	Enabled	16-bit	64-bit signed int or unsigned int. Users must ensure that the values assigned to 64-bit signed int fields are in range -(2^31 - 1) to +(2^31 - 1) and 64-bit unsigned int fields are in the range 0 to +(2^31 - 1). Otherwise, you may obtain incorrect results.	No. Users must ensure the safety based on the program compiled.

-fitodcalls

Promotes indirect-to-direct calls by placing conditional calls. Application or benchmarks that have a small and deterministic set of target functions for function pointers passed as call parameters benefit from this optimization. Indirect-to-direct call promotion transforms the code to use all possible determined targets under runtime checks and falls back to the original code for all the other cases. Runtime checks are introduced by the compiler for each of these possible function pointer targets followed by direct calls to the targets.

This is a link time optimization, which is invoked as -flto -fitodcalls

-fitodcallsbyclone

Performs value specialization for functions with function pointers passed as an argument. It does this specialization by generating a clone of the function. The cloning of the function happens in the call chain as needed, to allow conversion of indirect function call to direct call.

This complements -fitodcalls optimization and is also a link time optimization, which is invoked as -flto -fitodcallsbyclone.

-fremap-arrays

Transforms the data layout of a single dimensional array to provide better cache locality. This optimization is effective only under -flto, as the whole program needs to be analyzed to perform this optimization, which can be invoked as -flto -fremap-arrays.

-finline-aggressive

Enables improved inlining capability through better heuristics. This optimization is more effective when used with -flto, as the whole program analysis is required to perform this optimization, which can be invoked as -flto -finline-aggressive.

-fnt-store (non-temporal store)

Generates a non-temporal store instruction for array accesses in a loop with a large trip count.

-fnt-store=aggressive

This is an experimental option to generate non-temporal store instruction for array accesses in a loop, whose iteration count cannot be determined at compile time. In this case, the compiler assumes the iteration count to be huge.

Optimizations through driver -mllvm <options>

The following optimization options must be invoked through driver -mllvm <options>:

-enable-partial-unswitch

Enables partial loop unswitching, which is an enhancement to the existing loop unswitching optimization in LLVM. Partial loop unswitching hoists a condition inside a loop from a path for which the execution condition remains invariant, whereas the original loop unswitching works for a condition that is completely loop invariant. The condition inside the loop gets hoisted out from the invariant path, and the original loop is retained for the path where the condition is variant.

-aggressive-loop-unswitch

Experimental option that enables aggressive loop unswitching heuristic (including -enable-partial-unswitch) based on the usage of the branch conditional values. Loop unswitching leads to code bloat. Code bloat can be minimized if the hoisted condition is executed more often. This heuristic prioritizes the conditions based on the number of times they are used within the loop. The heuristic can be controlled with the following options:

• -unswitch-identical-branches-min-count=<n>

  • Enables unswitching of a loop with respect to a branch conditional value (B), where B appears in at least <n> compares in the loop. This option is enabled with -aggressive-loop-unswitch. The default value is 3.

  Usage: -mllvm -aggressive-loop-unswitch -mllvm -unswitch-identical-branches-min-count=<n>

  Where, n is a positive integer and lower value of <n> facilitates more unswitching.

• -unswitch-identical-branches-max-count=<n>

  • Enables unswitching of a loop with respect to a branch conditional value (B), where B appears in at most <n> compares in the loop. This option is enabled with -aggressive-loop-unswitch. The default value is 6.

  Usage: -mllvm -aggressive-loop-unswitch -mllvm -unswitch-identical-branches-max-count=<n>

  Where, n is a positive integer and higher value of <n> facilitates more unswitching.

  Note

  These options may facilitate more unswitching under some workloads. Since loop-unswitching inherently leads to code bloat, facilitating more unswitching may significantly increase the code size. Hence, it may also lead to longer compilation times.

-enable-strided-vectorization

Enables strided memory vectorization as an enhancement to the interleaved vectorization framework present in LLVM. It enables the effective use of gather and scatter kind of instruction patterns. This flag must be used along with the interleave vectorization flag.

-enable-epilog-vectorization

Enables vectorization of epilog-iterations as an enhancement to existing vectorization framework. This enables generation of an additional epilog vector loop version for the remainder iterations of the original vector loop. The vector size or factor of the original loop should be large enough to allow an effective epilog vectorization of the remaining iterations. This optimization takes place only when the original vector loop is vectorized with a vector width or factor of 16. This vectorization width of 16 may be overwritten by -min-width-epilog-vectorization command-line option.

-enable-redundant-movs

Removes any redundant mov operations including redundant loads from memory and stores to memory. This can be invoked using -Wl,-plugin-opt=-enable-redundant-movs.

-merge-constant

Attempts to promote frequently occurring constants to registers. The aim is to reduce the size of the instruction encoding for instructions using constants and obtain a performance improvement.

-function-specialize

Optimizes the functions with compile time constant formal arguments.

-lv-function-specialization

Generates specialized function versions when the loops inside function are vectorizable and the arguments are not aliased with each other.

-enable-vectorize-compares

Enables vectorization on certain loops with conditional breaks assuming the memory accesses are safely bound within the page boundary.

-inline-recursion=[1,2,3,4]

Enables inlining for recursive functions based on heuristics where the aggressiveness of heuristics increases with the level (1-4). The default level is 2. Higher levels may lead to code bloat due to expansion of recursive functions at call sites.

-inline-recursion Level and Their Effects

-inline-recursion value	Inline depth of heuristics used to enable inlining for recursive functions
1	1
2	1
3	1
4	10

This is more effective with -flto as the whole program needs to be analyzed to perform this optimization, which can be invoked as -flto -inline-recursion=[1,2,3,4].

-reduce-array-computations=[1,2,3]

Performs array data flow analysis and optimizes the unused array computations.

-reduce-array-computations Values and Their Effects

-reduce-array-computations value	Array elements eligible for elimination of computations
1	Unused
2	Zero valued
3	Both unused and zero valued

This optimization is effective with -flto as the whole program needs to be analyzed to perform this optimization, which can be invoked as -flto -reduce-array-computations=[1,2,3].

-global-vectorize-slp={true,false}

Vectorizes the straight-line code inside a basic block with data reordering vector operations. This option is set to true by default.

-region-vectorize

Experimental flag for enabling vectorization on certain loops with complex control flow, which the normal vectorizer cannot handle.

This optimization is effective with -flto as the whole program needs to be analyzed to perform this optimization, which can be invoked as -flto -region-vectorize.

-enable-x86-prefetching

Enables the generation of x86 prefetch instruction for the memory references inside a loop or inside an innermost loop of a loop nest to prefetch the second dimension of multidimensional array/memory references in the innermost loop of a loop nest. This is an experimental pass; its profitability is being improved.

-suppress-fmas

Identifies the reduction patterns on FMA and suppresses the FMA generation, as it is not profitable on the reduction patterns.

-enable-icm-vrp

Enables estimation of the virtual register pressure before performing loop invariant code motion. This estimation is used to control the number of loop invariants that will be hoisted during the loop invariant code motion.

-loop-splitting

Enables splitting of loops into multiple loops to eliminate the branches, which compare the loop induction with an invariant or constant expression. This option is enabled under -O3 by default. To disable this optimization, use -loop-splitting=false.

-enable-ipo-loop-split

Enables splitting of loops into multiple loops to eliminate the branches, which compares the loop induction with a constant expression. This constant expression can be derived through inter-procedural analysis. This option is enabled under -O3 by default. To disable this optimization, use -enable-ipo-loop-split=false.

-compute-interchange-order

Enables heuristic for finding the best possible interchange order for a loop nest. To enable this option, use -enable-loopinterchange. This option is set to false by default.

Usage:

-mllvm -enable-loopinterchange -mllvm -compute-interchange-order

-convert-pow-exp-to-int={true,false}

Converts the call to floating point exponent version of pow to its integer exponent version if the floating-point exponent can be converted to integer. This option is set to true by default.

-do-lock-reordering={none,normal,aggressive}

Reorders the control predicates in increasing order of complexity from outer predicate to inner when it is safe. The normal mode reorders simple expressions, while the aggressive mode reorders predicates involving function calls if no side effects are determined. This option is set to normal by default.

-fuse-tile-inner-loop

Enables fusion of adjacent tiled loops as a part of loop tiling transformation. This option is set to false by default.

-Hz,1,0x1 [Fortran]

Helps to preserve array index information for array access expressions which get linearized in the compiler front end. The preserved information is used by the compiler optimization phase in performing optimizations such as loop transformations. It is recommended that any user who is using optimizations such as loop transformations and other optimizations requiring de-linearized index expressions should use the Hz option. This option has no impact on any other aspects of the Flang front end.

Inline ASM statements

Inline assembly (ASM) statements allow a developer to include assembly instructions directly in either host or device code. While the ROCm compiler supports ASM statements, their use is not recommended for the following reasons:

• The compiler’s ability to produce both correct code and to optimize surrounding code is impeded.

• The compiler does not parse the content of the ASM statements and so cannot “see” its contents.

• The compiler must make conservative assumptions in an effort to retain correctness.

• The conservative assumptions may yield code that, on the whole, is less performant compared to code without ASM statements. It is possible that a syntactically correct ASM statement may cause incorrect runtime behavior.

• ASM statements are often ASIC-specific; code containing them is less portable and adds a maintenance burden to the developer if different ASICs are targeted.

• Writing correct ASM statements is often difficult; we strongly recommend thorough testing of any use of ASM statements.

Note

For developers who choose to include ASM statements in the code, AMD is interested in understanding the use case and appreciates feedback at RadeonOpenCompute/ROCm#issues

Miscellaneous OpenMP compiler features

This section discusses features that have been added or enhanced in the OpenMP compiler.

Offload-arch tool

An LLVM library and tool that is used to query the execution capability of the current system as well as to query requirements of a binary file. It is used by OpenMP device runtime to ensure compatibility of an image with the current system while loading it. It is compatible with target ID support and multi-image fat binary support.

Usage:

offload-arch [Options] [Optional lookup-value]

When used without an option, offload-arch prints the value of the first offload arch found in the underlying system. This can be used by various clang front ends. For example, to compile for OpenMP offloading on your current system, invoke clang with the following command:

clang -fopenmp -fopenmp-targets=`offload-arch` foo.c

If an optional lookup-value is specified, offload-arch will check if the value is either a valid offload-arch or a codename and look up requested additional information.

The following command provides all the information for offload-arch gfx906:

offload-arch gfx906 -v

The options are listed below:

-h

Prints the help message.

-a

Prints values for all devices. Do not stop at the first device found.

-m

Prints device code name (often found in pci.ids file).

-n

Prints numeric pci-id.

-t

Prints clang offload triple to use for the offload arch.

-v

Verbose. Implies: -a -m -n -t. For: all devices, prints codename, numeric value, and triple.

-f <file>

Prints offload requirements including offload-arch for each compiled offload image built into an application binary file.

-c

Prints offload capabilities of the underlying system. This option is used by the language runtime to select an image when multiple images are available. A capability must exist for each requirement of the selected image.

There are symbolic link aliases amdgpu-offload-arch and nvidia-arch for offload-arch. These aliases return 1 if no AMD GCN GPU or CUDA GPU is found. These aliases are useful in determining whether architecture-specific tests should be run or to conditionally load architecture-specific software.

Command-line simplification using offload-arch flag

Legacy mechanism of specifying offloading target for OpenMP involves using three flags, -fopenmp-targets, -Xopenmp-target, and -march. The first two flags take a target triple (like amdgcn-amd-amdhsa or nvptx64-nvidia-cuda), while the last flag takes device name (like gfx908 or sm_70) as input. Alternatively, users of ROCmCC compiler can use the flag —offload-arch for a combined effect of the above three flags.

Example:

# Legacy mechanism
clang -fopenmp -target x86_64-linux-gnu \
-fopenmp-targets=amdgcn-amd-amdhsa -Xopenmp-target=amdgcn-amd-amdhsa \
-march=gfx906 helloworld.c -o helloworld

Example:

# Using offload-arch flag
clang -fopenmp -target x86_64-linux-gnu \
--offload-arch=gfx906 helloworld.c -o helloworld.

To ensure backward compatibility, both styles are supported. This option is compatible with target ID support and multi-image fat binaries.

Target ID support for OpenMP

The ROCmCC compiler supports specification of target features along with the GPU name while specifying a target offload device in the command line, using -march or --offload-arch options. The compiled image in such cases is specialized for a given configuration of device and target features (target ID).

Example:

# compiling for a gfx908 device with XNACK paging support turned ON
clang -fopenmp -target x86_64-linux-gnu \
-fopenmp-targets=amdgcn-amd-amdhsa -Xopenmp-target=amdgcn-amd-amdhsa \
-march=gfx908:xnack+ helloworld.c -o helloworld

Example:

# compiling for a gfx908 device with SRAMECC support turned OFF
clang -fopenmp -target x86_64-linux-gnu \
-fopenmp-targets=amdgcn-amd-amdhsa -Xopenmp-target=amdgcn-amd-amdhsa \
-march=gfx908:sramecc- helloworld.c -o helloworld

Example:

# compiling for a gfx908 device with SRAMECC support turned ON and XNACK paging support turned OFF
clang -fopenmp -target x86_64-linux-gnu \
-fopenmp-targets=amdgcn-amd-amdhsa -Xopenmp-target=amdgcn-amd-amdhsa \
-march=gfx908:sramecc+:xnack- helloworld.c -o helloworld

The target ID specified on the command line is passed to the clang driver using target-feature flag, to the LLVM optimizer and back end using -mattr flag, and to linker using -plugin-opt=-mattr flag. This feature is compatible with offload-arch command-line option and multi-image binaries for multiple architectures.

Multi-image fat binary for OpenMP

The ROCmCC compiler is enhanced to generate binaries that can contain heterogenous images. This heterogeneity could be in terms of:

• Images of different architectures, like AMD GCN and NVPTX

• Images of same architectures but for different GPUs, like gfx906 and gfx908

• Images of same architecture and same GPU but for different target features, like gfx908:xnack+ and gfx908:xnack-

An appropriate image is selected by the OpenMP device runtime for execution depending on the capability of the current system. This feature is compatible with target ID support and offload-arch command-line options and uses offload-arch tool to determine capability of the current system.

Example:

clang -fopenmp -target x86_64-linux-gnu \
-fopenmp-targets=amdgcn-amd-amdhsa,amdgcn-amd-amdhsa \
-Xopenmp-target=amdgcn-amd-amdhsa -march=gfx906 \
-Xopenmp-target=amdgcn-amd-amdhsa -march=gfx908 \
helloworld.c -o helloworld

Example:

clang -fopenmp -target x86_64-linux-gnu \
--offload-arch=gfx906 \
--offload-arch=gfx908 \
helloworld.c -o helloworld

Example:

clang -fopenmp -target x86_64-linux-gnu \
-fopenmp-targets=amdgcn-amd-amdhsa,amdgcn-amd-amdhsa,amdgcn-amd-amdhsa,amdgcn-amd-amdhsa \
-Xopenmp-target=amdgcn-amd-amdhsa -march=gfx908:sramecc+:xnack+ \
-Xopenmp-target=amdgcn-amd-amdhsa -march=gfx908:sramecc-:xnack+ \
-Xopenmp-target=amdgcn-amd-amdhsa -march=gfx908:sramecc+:xnack- \
-Xopenmp-target=amdgcn-amd-amdhsa -march=gfx908:sramecc-:xnack- \
helloworld.c -o helloworld

The ROCmCC compiler creates an instance of toolchain for each unique combination of target triple and the target GPU (along with the associated target features). clang-offload-wrapper tool is modified to insert a new structure __tgt_image_info along with each image in the binary. Device runtime is also modified to query this structure to identify a compatible image based on the capability of the current system.

Unified shared memory

The following OpenMP pragma is available on MI200, and it must be executed with xnack+ support.

omp requires unified_shared_memory

For more details on unified shared memory refer to the Asynchronous behavior in OpenMP target regions section of the OpenMP Guide.

Support status of other Clang options

The following table lists the other Clang options and their support status.

Clang Options

Option	Support Status	Description
-###	Supported	Prints (but does not run) the commands to run for this compilation
--analyzer-output <value>	Supported	“Static analyzer report output format (`html
--analyze	Supported	Runs the static analyzer
-arcmt-migrate-emit-errors	Unsupported	Emits ARC errors even if the migrator can fix them
-arcmt-migrate-report-output  <value>	Unsupported	Output path for the plist report
-byteswapio	Supported	Swaps byte-order for unformatted input/output
-B <dir>	Supported	Adds <dir> to search path for binaries and object files used implicitly
-CC	Supported	Includes comments from within the macros in the preprocessed output
-cl-denorms-are-zero	Supported	OpenCL only. Allows denormals to be flushed to zero
-cl-fast-relaxed-math	Supported	OpenCL only. Sets -cl-finite-math-only and -cl-unsafe-math-optimizations and defines __FAST_RELAXED_MATH__
-cl-finite-math-only	Supported	OpenCL only. Allows floating-point optimizations that assume arguments and results are not NaNs or +-Inf
-cl-fp32-correctly-rounded-divide-sqrt	Supported	OpenCL only. Specifies that single-precision floating-point divide and sqrt used in the program source are correctly rounded
-cl-kernel-arg-info	Supported	OpenCL only. Generates kernel argument metadata
-cl-mad-enable	Supported	OpenCL only. Allows use of less precise MAD computations in the generated binary
-cl-no-signed-zeros	Supported	OpenCL only. Allows use of less precise no-signed-zeros computations in the generated binary
-cl-opt-disable	Supported	OpenCL only. Disables all optimizations. By default, optimizations are enabled.
-cl-single-precision-constant	Supported	OpenCL only. Treats double-precision floating-point constant as single precision constant
-cl-std= <value>	Supported	OpenCL language standard to compile for
-cl-strict-aliasing	Supported	OpenCL only. This option is added for compatibility with OpenCL 1.0.
-cl-uniform-work-group-size	Supported	OpenCL only. Defines the global work-size to be a multiple of the work-group size specified for clEnqueueNDRangeKernel
-cl-unsafe-math-optimizations	Supported	OpenCL only. Allows unsafe floating-point optimizations. Also implies -cl-no-signed-zeros and -cl-mad-enable
--config <value>	Supported	Specifies configuration file
--cuda-compile-host-device	Supported	Compiles CUDA code for both host and device (default). Has no effect on non-CUDA compilations
--cuda-device-only	Supported	Compiles CUDA code for device only
--cuda-host-only	Supported	Compiles CUDA code for host only. Has no effect on non-CUDA compilations
--cuda-include-ptx=<value>	Unsupported	Includes PTX for the following GPU architecture (e.g. sm_35) or “all.” May be specified more than once
--cuda-noopt-device-debug	Unsupported	Enables device-side debug info generation. Disables ptxas optimizations
--cuda-path-ignore-env	Unsupported	Ignores environment variables to detect CUDA installation
--cuda-path=<value>	Unsupported	CUDA installation path
-cxx-isystem <directory>	Supported	Adds a directory to the C++ SYSTEM include search path
-C	Supported	Includes comments in the preprocessed output
-c	Supported	Runs only preprocess, compile, and assemble steps
-dD	Supported	Prints macro definitions in -E mode in addition to the normal output
-dependency-dot <value>	Supported	Writes DOT-formatted header dependencies to the specified filename
-dependency-file <value>	Supported	Writes dependency output to the specified filename (or -)
-dI	Supported	Prints include directives in -E mode in addition to the normal output
-dM	Supported	Prints macro definitions in -E mode instead of the normal output
-dsym-dir <dir>	Unsupported	Outputs dSYMs (if any) to the specified directory
-D <macro>	Supported	=<value>. Defines <macro> to <value> (or 1 if <value> omitted)
-emit-ast	Supported	Emits Clang AST files for source inputs
-emit-interface-stubs	Supported	Generates interface stub files
-emit-llvm	Supported	Uses the LLVM representation for assembler and object files
-emit-merged-ifs	Supported	Generates interface stub files and emits merged text not binary
--emit-static-lib	Supported	Enables linker job to emit a static library
-enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang	Supported	Declares enabling trivial automatic variable initialization to zero for benchmarking purpose with the knowledge that it will eventually be removed
-E	Supported	Runs the preprocessor only
-fAAPCSBitfieldLoad	Unsupported	Follows the AAPCS standard where all volatile bit-field writes generate at least one load (ARM only)
-faddrsig	Supported	Emits an address-significance table
-faligned-allocation	Supported	Enables C++17 aligned allocation functions
-fallow-editor-placeholders	Supported	Treats editor placeholders as valid source code
-fallow-fortran-gnu-ext	Supported	Allows Fortran GNU extensions
-fansi-escape-codes	Supported	Uses ANSI escape codes for diagnostics
-fapple-kext	Unsupported	Uses Apple’s kernel extensions ABI
-fapple-link-rtlib	Unsupported	Forces linking of the clang built-ins runtime library
-fapple-pragma-pack	Unsupported	Enables Apple gcc-compatible #pragma pack handling
-fapplication-extension	Unsupported	Restricts code to those available for App Extensions
-fbackslash	Supported	Treats backslash as C-style escape character
-fbasic-block-sections= <value>	Supported	“Places each function’s basic blocks in unique sections (ELF Only) : all | labels | none | list= <file>”
-fblocks	Supported	Enables the ‘blocks’ language feature
-fborland-extensions	Unsupported	Accepts non-standard constructs supported by the Borland compile
-fbuild-session-file= <file>	Supported	Uses the last modification time of <file> as the build session timestamp
-fbuild-session-timestamp= <time since Epoch in seconds>	Supported	Specifies starting time of the current build session
-fbuiltin-module-map	Unsupported	Loads the Clang built-ins module map file
-fcall-saved-x10	Unsupported	Makes the x10 register call-saved (AArch64 only)
-fcall-saved-x11	Unsupported	Makes the x11 register call-saved (AArch64 only)
-fcall-saved-x12	Unsupported	Makes the x12 register call-saved (AArch64 only)
-fcall-saved-x13	Unsupported	Makes the x13 register call-saved (AArch64 only)
-fcall-saved-x14	Unsupported	Makes the x14 register call-saved (AArch64 only)
-fcall-saved-x15	Unsupported	Makes the x15 register call-saved (AArch64 only)
-fcall-saved-x18	Unsupported	Makes the x18 register call-saved (AArch64 only)
-fcall-saved-x8	Unsupported	Makes the x8 register call-saved (AArch64 only)
-fcall-saved-x9	Unsupported	Makes the x9 register call-saved (AArch64 only)
-fcf-protection= <value>	Unsupported	Specifies the instrument control-flow architecture protection using options: return, branch, full, none
-fcf-protection	Unsupported	Enables cf-protection in ‘full’ mode
-fchar8_t	Supported	Enables C++ built-in type char8_t
-fclang-abi-compat= <version>	Supported	Attempts to match the ABI of Clang <version>
-fcolor-diagnostics	Supported	Enables colors in diagnostics
-fcomment-block-commands= <arg>	Supported	Treats each comma-separated argument in <arg> as a documentation comment block command
-fcommon	Supported	Places uninitialized global variables in a common block
-fcomplete-member-pointers	Supported	Requires member pointer base types to be complete if they are significant under the Microsoft ABI
-fconvergent-functions	Supported	Assumes functions to be convergent
-fcoroutines-ts	Supported	Enables support for the C++ Coroutines TS
-fcoverage-mapping	Unsupported	Generates coverage mapping to enable code coverage analysis
-fcs-profile-generate= <directory>	Unsupported	Generates instrumented code to collect context-sensitive execution counts into <directory>/default.profraw (overridden by LLVM_PROFILE_FILE env var)
-fcs-profile-generate	Unsupported	Generates instrumented code to collect context-sensitive execution counts into default.profraw (overridden by LLVM_PROFILE_FILE env var)
-fcuda-approx-transcendentals	Unsupported	Uses approximate transcendental functions
-fcuda-flush-denormals-to-zero	Supported	Flushes denormal floating-point values to zero in CUDA device mode
-fcuda-short-ptr	Unsupported	Uses 32-bit pointers for accessing const/local/shared address spaces
-fcxx-exceptions	Supported	Enables C++ exceptions
-fdata-sections	Supported	Places each data in its section
-fdebug-compilation-dir <value>	Supported	Specifies the compilation directory for embedding the debug info
-fdebug-default-version= <value>	Supported	Specifies the default DWARF version to use, if a -g option caused DWARF debug info to be produced
-fdebug-info-for-profiling	Supported	Emits extra debug info to make the sample profile more accurate
-fdebug-macro	Supported	Emits macro debug information
-fdebug-prefix-map= <value>	Supported	Remaps file source paths in debug info
-fdebug-ranges-base-address	Supported	Uses DWARF base address selection entries in .debug ranges
-fdebug-types-section	Supported	Places debug types in their section (ELF only)
-fdeclspec	Supported	Allows __declspec as a keyword
-fdelayed-template-parsing	Supported	Parses templated function definitions at the end of the translation unit
-fdelete-null-pointer-checks	Supported	Treats usage of null pointers as undefined behavior (default)
-fdiagnostics-absolute-paths	Supported	Prints absolute paths in diagnostics
-fdiagnostics-hotness-threshold= <number>	Unsupported	Prevents optimization remarks from being output if they do not have at least the specified number of profile count
-fdiagnostics-parseable-fixits	Supported	Prints fix-its in machine parseable form
-fdiagnostics-print-source-range-info	Supported	Prints source range spans in numeric form
-fdiagnostics-show-hotness	Unsupported	Enables profile hotness information in diagnostic line
-fdiagnostics-show-note-include-stack	Supported	Displays include stacks for diagnostic notes
-fdiagnostics-show-option	Supported	Prints option name with mappable diagnostics
-fdiagnostics-show-template-tree	Supported	Prints a template comparison tree for differing templates
-fdigraphs	Supported	Enables alternative token representations ‘ <:’, ‘:>’, ‘ <%’, ‘%>’, ‘%:’, ‘%:%:’ (default)
-fdiscard-value-names	Supported	Discards value names in LLVM IR
-fdollars-in-identifiers	Supported	Allows “$” in identifiers
-fdouble-square-bracket-attributes	Supported	Enables ‘[[]]’ attributes in all C and C++ language modes
-fdwarf-exceptions	Unsupported	Uses DWARF style exceptions
-feliminate-unused-debug-types	Supported	Eliminates debug info for defined but unused types
-fembed-bitcode-marker	Supported	Embeds placeholder LLVM IR data as a marker
-fembed-bitcode= <option>	Supported	Embeds LLVM bitcode (option: off, all, bitcode, marker)
-fembed-bitcode	Supported	Embeds LLVM IR bitcode as data
-femit-all-decls	Supported	Emits all declarations, even if unused
-femulated-tls	Supported	Uses emutls functions to access thread_local variables
-fenable-matrix	Supported	Enables matrix data type and related built-in functions
-fexceptions	Supported	Enables support for exception handling
-fexperimental-new-constant-interpreter	Supported	Enables the experimental new constant interpreter
-fexperimental-new-pass-manager	Supported	Enables an experimental new pass manager in LLVM
-fexperimental-relative-c+±abi-vtables	Supported	Uses the experimental C++ class ABI for classes with virtual tables
-fexperimental-strict-floating-point	Supported	Enables experimental strict floating point in LLVM
-ffast-math	Supported	Allows aggressive, lossy floating-point optimizations
-ffile-prefix-map= <value>	Supported	Remaps file source paths in debug info and predefined preprocessor macros
-ffine-grained-bitfield-accesses	Supported	Uses separate accesses for consecutive bitfield runs with legal widths and alignments
-ffixed-form	Supported	Enables fixed-form format for Fortran
-ffixed-point	Supported	Enables fixed point types
-ffixed-r19	Unsupported	Reserves the r19 register (Hexagon only)
-ffixed-r9	Unsupported	Reserves the r9 register (ARM only)
-ffixed-x10	Unsupported	Reserves the x10 register (AArch64/RISC-V only)
-ffixed-x11	Unsupported	Reserves the x11 register (AArch64/RISC-V only)
-ffixed-x12	Unsupported	Reserves the x12 register (AArch64/RISC-V only)
-ffixed-x13	Unsupported	Reserves the x13 register (AArch64/RISC-V only)
-ffixed-x14	Unsupported	Reserves the x14 register (AArch64/RISC-V only)
-ffixed-x15	Unsupported	Reserves the x15 register (AArch64/RISC-V only)
-ffixed-x16	Unsupported	Reserves the x16 register (AArch64/RISC-V only)
-ffixed-x17	Unsupported	Reserves the x17 register (AArch64/RISC-V only)
-ffixed-x18	Unsupported	Reserves the x18 register (AArch64/RISC-V only)
-ffixed-x19	Unsupported	Reserves the x19 register (AArch64/RISC-V only)
-ffixed-x1	Unsupported	Reserves the x1 register (AArch64/RISC-V only)
-ffixed-x20	Unsupported	Reserves the x20 register (AArch64/RISC-V only)
-ffixed-x21	Unsupported	Reserves the x21 register (AArch64/RISC-V only)
-ffixed-x22	Unsupported	Reserves the x22 register (AArch64/RISC-V only)
-ffixed-x23	Unsupported	Reserves the x23 register (AArch64/RISC-V only)
-ffixed-x24	Unsupported	Reserves the x24 register (AArch64/RISC-V only)
-ffixed-x25	Unsupported	Reserves the x25 register (AArch64/RISC-V only)
-ffixed-x26	Unsupported	Reserves the x26 register (AArch64/RISC-V only)
-ffixed-x27	Unsupported	Reserves the x27 register (AArch64/RISC-V only)
-ffixed-x28	Unsupported	Reserves the x28 register (AArch64/RISC-V only)
-ffixed-x29	Unsupported	Reserves the x29 register (AArch64/RISC-V only)
-ffixed-x2	Unsupported	Reserves the x2 register (AArch64/RISC-V only)
-ffixed-x30	Unsupported	Reserves the x30 register (AArch64/RISC-V only)
-ffixed-x31	Unsupported	Reserves the x31 register (AArch64/RISC-V only)
-ffixed-x3	Unsupported	Reserves the x3 register (AArch64/RISC-V only)
-ffixed-x4	Unsupported	Reserves the x4 register (AArch64/RISC-V only)
-ffixed-x5	Unsupported	Reserves the x5 register (AArch64/RISC-V only)
-ffixed-x6	Unsupported	Reserves the x6 register (AArch64/RISC-V only)
-ffixed-x7	Unsupported	Reserves the x7 register (AArch64/RISC-V only)
-ffixed-x8	Unsupported	Reserves the x8 register (AArch64/RISC-V only)
-ffixed-x9	Unsupported	Reserves the x9 register (AArch64/RISC-V only)
-fforce-dwarf-frame	Supported	Mandatorily emits a debug frame section
-fforce-emit-vtables	Supported	Emits more virtual tables to improve devirtualization
-fforce-enable-int128	Supported	Enables support for int128_t type
-ffp-contract= <value>	Supported	Forms fused FP ops (e.g. FMAs): fast (everywhere) \ on (according to FP_CONTRACT pragma) \ off (never fuse). Default is “fast” for CUDA/HIP and “on” for others.
-ffp-exception-behavior= <value>	Supported	Specifies the exception behavior of floating-point operations
-ffp-model= <value>	Supported	Controls the semantics of floating-point calculations
-ffree-form	Supported	Enables free-form format for Fortran
-ffreestanding	Supported	Asserts the compilation to take place in a freestanding environment
-ffunc-args-alias	Supported	Allows the function arguments aliases (equivalent to ansi alias)
-ffunction-sections	Supported	Places each function in its section
-fglobal-isel	Supported	Enables the global instruction selector
-fgnu-keywords	Supported	Allows GNU-extension keywords regardless of a language standard
-fgnu-runtime	Unsupported	Generates output compatible with the standard GNU Objective-C runtime
-fgnu89-inline	Unsupported	Uses the gnu89 inline semantics
-fgnuc-version= <value>	Supported	Sets various macros to claim compatibility with the given GCC version (default is 4.2.1)
-fgpu-allow-device-init	Supported	Allows device-side init function in HIP
-fgpu-rdc	Supported	Generates relocatable device code, also known as separate compilation mode
-fhip-new-launch-api	Supported	Uses new kernel launching API for HIP
-fignore-exceptions	Supported	Enables support for ignoring exception handling constructs
-fimplicit-module-maps	Unsupported	Implicitly searches the file system for module map files
-finline-functions	Supported	Inlines suitable functions
-finline-hint-functions	Supported	Inlines functions that are (explicitly or implicitly) marked inline
-finstrument-function-entry-bare	Unsupported	Allows instrument function entry only after inlining, without arguments to the instrumentation call
-finstrument-functions-after-inlining	Unsupported	Similar to -finstrument-functions option but inserts the calls after inlining
-finstrument-functions	Unsupported	Generates calls to instrument function entry and exit
-fintegrated-as	Supported	Enables the integrated assembler
-fintegrated-cc1	Supported	Runs cc1 in-process
-fjump-tables	Supported	Uses jump tables for lowering switches
-fkeep-static-consts	Supported	Keeps static const variables if unused
-flax-vector-conversions= <value>	Supported	Enables implicit vector bit-casts
-flto-jobs= <value>	Unsupported	Controls the backend parallelism of -flto=thin (A default value of 0 means the number of threads will be derived from the number of CPUs detected.)
-flto= <value>	Unsupported	Sets LTO mode to either “full” or “thin”
-flto	Unsupported	Enables LTO in “full” mode
-fmacro-prefix-map= <value>	Supported	Remaps file source paths in predefined preprocessor macros
-fmath-errno	Supported	Requires math functions to indicate errors by setting errno
-fmax-tokens= <value>	Supported	Specifies max total number of preprocessed tokens for -Wmax-tokens
-fmax-type-align= <value>	Supported	Specifies the maximum alignment to enforce on pointers lacking an explicit alignment
-fmemory-profile	Supported	Enables heap memory profiling
-fmerge-all-constants	Supported	Allows merging of constants
-fmessage-length= <value>	Supported	Formats message diagnostics to fit within N columns
-fmodule-file=[ <name>=] <file>	Unsupported	Specifies the mapping of module name to precompiled module file. Loads a module file if name is omitted
-fmodule-map-file= <file>	Unsupported	Loads the specified module map file
-fmodule-name= <name>	Unsupported	Specifies the name of the module to build
-fmodules-cache-path= <directory>	Unsupported	Specifies the module cache path
-fmodules-decluse	Unsupported	Asserts declaration of modules used within a module
-fmodules-disable-diagnostic-validation	Unsupported	Disables validation of the diagnostic options when loading the module
-fmodules-ignore-macro= <value>	Unsupported	Ignores the definition of the specified macro when building and loading modules
-fmodules-prune-after= <seconds>	Unsupported	Specifies the interval (in seconds) after which a module file is to be considered unused
-fmodules-prune-interval= <seconds>	Unsupported	Specifies the interval (in seconds) between attempts to prune the module cache
-fmodules-search-all	Unsupported	Searches even non-imported modules to resolve references
-fmodules-strict-decluse	Unsupported	Similar to -fmodules-decluse option but requires all headers to be in the modules
-fmodules-ts	Unsupported	Enables support for the C++ Modules TS
-fmodules-user-build-path <directory>	Unsupported	Specifies the module user build path
-fmodules-validate-input-files-content	Supported	Validates PCM input files based on content if mtime differs
-fmodules-validate-once-per-build-session	Unsupported	Prohibits verification of input files for the modules if the module has been successfully validated or loaded during the current build session
-fmodules-validate-system-headers	Supported	Validates the system headers that a module depends on when loading the module
-fmodules	Unsupported	Enables the “modules” language feature
-fms-compatibility-version= <value>	Supported	Specifies the dot-separated value representing the Microsoft compiler version number to report in _MSC_VER (0 = do not define it (default))
-fms-compatibility	Supported	Enables full Microsoft Visual C++ compatibility
-fms-extensions	Supported	Accepts some non-standard constructs supported by the Microsoft compiler
-fmsc-version= <value>	Supported	Specifies the Microsoft compiler version number to report in _MSC_VER (0 = do not define it (default))
-fnew-alignment= <align>	Supported	Specifies the largest alignment guaranteed by “::operator new(size_t)”
-fno-addrsig	Supported	Prohibits emitting an address-significance table
-fno-allow-fortran-gnu-ext	Supported	Allows Fortran GNU extensions
-fno-assume-sane-operator-new	Supported	Prohibits the assumption that C++’s global operator new cannot alias any pointer
-fno-autolink	Supported	Disables generation of linker directives for automatic library linking
-fno-backslash	Supported	Allows treatment of backslash like any other character in character strings
-fno-builtin- <value>	Supported	Disables implicit built-in knowledge of a specific function
-fno-builtin	Supported	Disables implicit built-in knowledge of functions
-fno-c+±static-destructors	Supported	Disables C++ static destructor registration
-fno-char8_t	Supported	Disables C++ built-in type char8_t
-fno-color-diagnostics	Supported	Disables colors in diagnostics
-fno-common	Supported	Compiles common globals like normal definitions
-fno-complete-member-pointers	Supported	Eliminates the requirement for the member pointer base types to be complete if they would be significant under the Microsoft ABI
-fno-constant-cfstrings	Supported	Disables creation of CodeFoundation-type constant strings
-fno-coverage-mapping	Supported	Disables code coverage analysis
-fno-crash-diagnostics	Supported	Disables auto-generation of preprocessed source files and a script for reproduction during a Clang crash
-fno-cuda-approx-transcendentals	Unsupported	Eliminates the usage of approximate transcendental functions
-fno-debug-macro	Supported	Prohibits emitting the macro debug information
-fno-declspec	Unsupported	Disallows declspec as a keyword
-fno-delayed-template-parsing	Supported	Disables delayed template parsing
-fno-delete-null-pointer-checks	Supported	Prohibits the treatment of null pointers as undefined behavior
-fno-diagnostics-fixit-info	Supported	Prohibits including fixit information in diagnostics
-fno-digraphs	Supported	Disallows alternative token representations “ <:’, ‘:>’, ‘ <%’, ‘%>’, ‘%:’, ‘%:%:”
-fno-discard-value-names	Supported	Prohibits discarding value names in LLVM IR
-fno-dollars-in-identifiers	Supported	Disallows ‘$’ in identifiers
-fno-double-square-bracket-attributes	Supported	Disables ‘[[]]’ attributes in all C and C++ language modes
-fno-elide-constructors	Supported	Disables C++ copy constructor elision
-fno-elide-type	Supported	Prohibits eliding types when printing diagnostics
-fno-eliminate-unused-debug-types	Supported	Emits debug info for defined but unused types
-fno-exceptions	Supported	Disables support for exception handling
-fno-experimental-new-pass-manager	Supported	Disables an experimental new pass manager in LLVM
-fno-experimental-relative-c+±abi-vtables	Supported	Prohibits using the experimental C++ class ABI for classes with virtual tables
-fno-fine-grained-bitfield-accesses	Supported	Allows using large-integer access for consecutive bitfield runs
-fno-fixed-form	Supported	Disables fixed-form format for Fortran
-fno-fixed-point	Supported	Disables fixed point types
-fno-force-enable-int128	Supported	Disables support for int128_t type
-fno-fortran-main	Supported	Prohibits linking in Fortran main
-fno-free-form	Supported	Disables free-form format for Fortran
-fno-func-args-alias	Supported	Allows the function argument alias (equivalent to ansi alias)
-fno-global-isel	Supported	Disables the global instruction selector
-fno-gnu-inline-asm	Supported	Disables GNU style inline asm
-fno-gpu-allow-device-init	Supported	Disallows device-side init function in HIP
-fno-hip-new-launch-api	Supported	Disallows new kernel launching API for HIP
-fno-integrated-as	Supported	Disables the integrated assembler
-fno-integrated-cc1	Supported	Spawns a separate process for each cc1
-fno-jump-tables	Supported	Disallows jump tables for lowering switches
-fno-keep-static-consts	Supported	Prohibits keeping static const variables if unused
-fno-lto	Supported	Disables LTO mode (default)
-fno-memory-profile	Supported	Disables heap memory profiling
-fno-merge-all-constants	Supported	Disallows merging of constants
-fno-no-access-control	Supported	Disables C++ access control
-fno-objc-infer-related-result-type	Supported	Prohibits inferring Objective-C related result type based on the method family
-fno-operator-names	Supported	Disallows treatment of C++ operator name keywords as synonyms for operators
-fno-pch-codegen	Supported	Disallows code-generation for uses of the PCH that assumes building an explicit object file for the PCH
-fno-pch-debuginfo	Supported	Prohibits generation of debug info for types in an object file built from this PCH or elsewhere
-fno-plt	Supported	Asserts usage of GOT indirection instead of PLT to make external function calls (x86 only)
-fno-preserve-as-comments	Supported	Prohibits preserving comments in inline assembly
-fno-profile-generate	Supported	Disables generation of profile instrumentation
-fno-profile-instr-generate	Supported	Disables generation of profile instrumentation
-fno-profile-instr-use	Supported	Disables usage of instrumentation data for profile-guided optimization
-fno-register-global-dtors-with-atexit	Supported	Disallows usage of atexit or __cxa_atexit to register global destructors
-fno-rtlib-add-rpath	Supported	Prohibits adding -rpath with architecture-specific resource directory to the linker flags
-fno-rtti-data	Supported	Disables generation of RTTI data
-fno-rtti	Supported	Disables generation of rtti information
-fno-sanitize-address-poison-custom-array-cookie	Supported on Host only	Disables poisoning of array cookies when using custom operator new[] in AddressSanitizer
-fno-sanitize-address-use-after-scope	Supported on Host only	Disables use-after-scope detection in AddressSanitizer
-fno-sanitize-address-use-odr-indicator	Supported on Host only	Disables ODR indicator globals
-fno-sanitize-blacklist	Supported on Host only	Prohibits using blacklist file for sanitizers
-fno-sanitize-cfi-canonical-jump-tables	Supported on Host only	Prohibits making the jump table addresses canonical in the symbol table
-fno-sanitize-cfi-cross-dso	Supported on Host only	Disables control flow integrity (CFI) checks for cross-DSO calls
-fno-sanitize-coverage= <value>	Supported on Host only	Disables specified features of coverage instrumentation for Sanitizers
-fno-sanitize-memory-track-origins	Supported on Host only	Disables origins tracking in MemorySanitizer
-fno-sanitize-memory-use-after-dtor	Supported on Host only	Disables use-after-destroy detection in MemorySanitizer
-fno-sanitize-recover= <value>	Supported on Host only	Disables recovery for specified sanitizers
-fno-sanitize-stats	Supported on Host only	Disables sanitizer statistics gathering
-fno-sanitize-thread-atomics	Supported on Host only	Disables atomic operations instrumentation in ThreadSanitizer
-fno-sanitize-thread-func-entry-exit	Supported on Host only	Disables function entry/exit instrumentation in ThreadSanitizer
-fno-sanitize-thread-memory-access	Supported on Host only	Disables memory access instrumentation in ThreadSanitizer
-fno-sanitize-trap= <value>	Supported on Host only	Disables trapping for specified sanitizers
-fno-sanitize-trap	Supported on Host only	Disables trapping for all sanitizers
-fno-short-wchar	Supported	Forces wchar_t to be an unsigned int
-fno-show-column	Supported	Prohibits including column number on diagnostics
-fno-show-source-location	Supported	Prohibits including source location information with diagnostics
-fno-signed-char	Supported	char is unsigned
-fno-signed-zeros	Supported	Allows optimizations that ignore the sign of floating point zeros
-fno-spell-checking	Supported	Disables spell-check
-fno-split-machine-functions	Supported	Disables late function splitting using profile information (x86 ELF)
-fno-stack-clash-protection	Supported	Disables stack clash protection
-fno-stack-protector	Supported	Disables the use of stack protectors
-fno-standalone-debug	Supported	Limits debug information produced to reduce size of debug binary
-fno-strict-float-cast-overflow	Supported	Relaxes language rules and tries to match the behavior of the target’s native float-to-int conversion instructions
-fno-strict-return	Supported	Prohibits treating the control flow paths that fall off the end of a non-void function as unreachable
-fno-sycl	Unsupported	Disables SYCL kernels compilation for device
-fno-temp-file	Supported	Asserts direct creation of compilation output files. This may lead to incorrect incremental builds if the compiler crashes.
-fno-threadsafe-statics	Supported	Prohibits emitting code to make initialization of local statics thread safe
-fno-trigraphs	Supported	Prohibits processing trigraph sequences
-fno-unique-section-names	Supported	Prohibits the usage of unique names for text and data sections
-fno-unroll-loops	Supported	Turns off the loop unroller
-fno-use-cxa-atexit	Supported	Prohibits the usage of __cxa_atexit for calling destructors
-fno-use-flang-math-libs	Supported	Asserts the usage of Flang internal runtime math library instead of LLVM math intrinsics
-fno-use-init-array	Supported	Asserts the usage of .ctors/.dtors instead of .init_array/.fini_array
-fno-visibility-inlines-hidden-static-local-var	Supported	Disables -fvisibility-inlines-hidden-static-local-var (This is the default on non-darwin targets.)
-fno-xray-function-index	Unsupported	Allows omitting function index section at the expense of single-function patching performance
-fno-zero-initialized-in-bss	Supported	Prohibits placing zero initialized data in BSS
-fobjc-arc-exceptions	Unsupported	Asserts using EH-safe code when synthesizing retains and releases in -fobjc-arc
-fobjc-arc	Unsupported	Synthesizes retain and release calls for Objective-C pointers
-fobjc-exceptions	Unsupported	Enables Objective-C exceptions
-fobjc-runtime= <value>	Unsupported	Specifies the target Objective-C runtime kind and version
-fobjc-weak	Unsupported	Enables ARC-style weak references in Objective-C
-fopenmp-simd	Unsupported	Emits OpenMP code only for SIMD-based constructs
-fopenmp-targets= <value>	Unsupported	Specifies a comma-separated list of triples OpenMP offloading targets to be supported
-fopenmp	Unsupported	Parses OpenMP pragmas and generates parallel code
-foptimization-record-file= <file>	Supported	Specifies the output name of the file containing the optimization remarks. Implies -fsave-optimization-record. On Darwin platforms, this cannot be used with multiple -arch <arch> options.
-foptimization-record-passes= <regex>	Supported	Exclusively allows the inclusion of passes that match a specified regular expression in the generated optimization record (By default, include all passes.)
-forder-file-instrumentation	Supported	Generates instrumented code to collect order file into default.profraw file (overridden by ‘=’ form of option or LLVM_PROFILE_FILE env var)
-fpack-struct= <value>	Unsupported	Specifies the default maximum struct packing alignment
-fpascal-strings	Supported	Recognizes and constructs Pascal-style string literals
-fpass-plugin= <dsopath>	Supported	Loads pass plugin from a dynamic shared object file (only with new pass manager)
-fpatchable-function-entry= <N,M>	Supported	Generates M NOPs before function entry and N-M NOPs after function entry
-fpcc-struct-return	Unsupported	Overrides the default ABI to return all structs on the stack
-fpch-codegen	Supported	Generates code for using this PCH that assumes building an explicit object file for the PCH
-fpch-debuginfo	Supported	Generates debug info for types exclusively in an object file built from this PCH
-fpch-instantiate-templates	Supported	Instantiates templates already while building a PCH
-fpch-validate-input-files-content	Supported	Validates PCH input files based on the content if mtime differs
-fplugin= <dsopath>	Supported	Loads the named plugin (dynamic shared object)
-fprebuilt-module-path= <directory>	Unsupported	Specifies the prebuilt module path
-fprofile-exclude-files= <value>	Unsupported	Exclusively instruments those functions from files where names do not match all the regexes separated by a semicolon
-fprofile-filter-files= <value>	Unsupported	Exclusively instruments those functions from files where names match any regex separated by a semicolon
-fprofile-generate= <directory>	Unsupported	Generates instrumented code to collect execution counts into <directory>/default.profraw (overridden by LLVM_PROFILE_FILE env var)
-fprofile-generate	Unsupported	Generates instrumented code to collect execution counts into default.profraw (overridden by LLVM_PROFILE_FILE env var)
-fprofile-instr-generate= <file>	Unsupported	Generates instrumented code to collect execution counts into <file> (overridden by LLVM_PROFILE_FILE env var)
-fprofile-instr-generate	Unsupported	Generates instrumented code to collect execution counts into default.profraw file (overridden by ‘=’ form of option or LLVM_PROFILE_FILE env var)
-fprofile-instr-use= <value>	Unsupported	Uses instrumentation data for profile-guided optimization
-fprofile-remapping-file= <file>	Unsupported	Uses the remappings described in <file> to match the profile data against the names in the program
-fprofile-sample-accurate	Unsupported	Specifies that the sample profile is accurate
-fprofile-sample-use= <value>	Unsupported	Enables sample-based profile-guided optimizations
-fprofile-use= <pathname>	Unsupported	Uses instrumentation data for profile-guided optimization. If pathname is a directory, it reads from <pathname>/default.profdata. Otherwise, it reads from file <pathname>.
-freciprocal-math	Supported	Allows division operations to be reassociated
-freg-struct-return	Unsupported	Overrides the default ABI to return small structs in registers
-fregister-global-dtors-with-atexit	Supported	Uses atexit or __cxa_atexit to register global destructors
-frelaxed-template-template-args	Supported	Enables C++17 relaxed template argument matching
-freroll-loops	Supported	Turns on loop reroller
-fropi	Unsupported	Generates read-only position independent code (ARM only)
-frtlib-add-rpath	Supported	Adds -rpath with architecture-specific resource directory to the linker flags
-frwpi	Unsupported	Generates read-write position-independent code (ARM only)
-fsanitize-address-field-padding= <value>	Supported on Host only	Specifies the level of field padding for AddressSanitizer
-fsanitize-address-globals-dead-stripping	Supported on Host only	Enables linker dead stripping of globals in AddressSanitizer
-fsanitize-address-poison-custom-array-cookie	Supported on Host only	Enables poisoning of array cookies when using custom operator new[] in AddressSanitizer
-fsanitize-address-use-after-scope	Supported on Host only	Enables use-after-scope detection in AddressSanitizer
-fsanitize-address-use-odr-indicator	Supported on Host only	Enables ODR indicator globals to avoid false ODR violation reports in partially sanitized programs at the cost of an increase in binary size
-fsanitize-blacklist= <value>	Supported on Host only	Specifies the path to blacklisted files for sanitizers
-fsanitize-cfi-canonical-jump-tables	Supported on Host only	Makes the jump table addresses canonical in the symbol table
-fsanitize-cfi-cross-dso	Supported on Host only	Enables control flow integrity (CFI) checks for cross-DSO calls
-fsanitize-cfi-icall-generalize-pointers	Supported on Host only	Generalizes pointers in CFI indirect call type signature checks
-fsanitize-coverage-allowlist= <value>	Supported on Host only	Restricts sanitizer coverage instrumentation exclusively to modules and functions that match the provided special case list, except the blocked ones
-fsanitize-coverage-blacklist= <value>	Supported on Host only	Deprecated; use -fsanitize-coverage-blocklist= instead.
-fsanitize-coverage-blocklist= <value>	Supported on Host only	Disables sanitizer coverage instrumentation for modules and functions that match the provided special case list, even the allowed ones
-fsanitize-coverage-whitelist= <value>	Supported on Host only	Deprecated; use -fsanitize-coverage-allowlist= instead.
-fsanitize-coverage= <value>	Supported on Host only	Specifies the type of coverage instrumentation for Sanitizers
-fsanitize-hwaddress-abi= <value>	Supported on Host only	Selects the HWAddressSanitizer ABI to target (interceptor or platform, default interceptor). This option is currently unused.
-fsanitize-memory-track-origins= <value>	Supported on Host only	Enables origins tracking in MemorySanitizer
-fsanitize-memory-track-origins	Supported on Host only	Enables origins tracking in MemorySanitizer
-fsanitize-memory-use-after-dtor	Supported on Host only	Enables use-after-destroy detection in MemorySanitizer
-fsanitize-recover= <value>	Supported on Host only	Enables recovery for specified sanitizers
-fsanitize-stats	Supported on Host only	Enables sanitizer statistics gathering
-fsanitize-system-blacklist= <value>	Supported on Host only	Specifies the path to system blacklist files for sanitizers
-fsanitize-thread-atomics	Supported on Host only	Enables atomic operations instrumentation in ThreadSanitizer (default)
-fsanitize-thread-func-entry-exit	Supported on Host only	Enables function entry/exit instrumentation in ThreadSanitizer (default)
-fsanitize-thread-memory-access	Supported on Host only	Enables memory access instrumentation in ThreadSanitizer (default)
-fsanitize-trap= <value>	Supported on Host only	Enables trapping for specified sanitizers
-fsanitize-trap	Supported on Host only	Enables trapping for all sanitizers
-fsanitize-undefined-strip-path-components= <number>	Supported on Host only	Strips (or keeps only, if negative) the given number of path components when emitting check metadata
-fsanitize= <check>	Supported on Host only	Turns on runtime checks for various forms of undefined or suspicious behavior. See user manual for available checks.
-fsave-optimization-record= <format>	Supported	Generates an optimization record file in the specified format
-fsave-optimization-record	Supported	Generates a YAML optimization record file
-fseh-exceptions	Supported	Uses SEH style exceptions
-fshort-enums	Supported	Allocates to an enum type only as many bytes as it needs for the declared range of possible values
-fshort-wchar	Unsupported	Forces wchar_t to be a short unsigned int
-fshow-overloads= <value>	Supported	Specifies which overload candidates are shown when overload resolution fails. Values = best\all; default value = “all”
-fsigned-char	Supported	Asserts that the char is signed
-fsized-deallocation	Supported	Enables C++14 sized global deallocation functions
-fsjlj-exceptions	Supported	Uses SjLj style exceptions
-fslp-vectorize	Supported	Enables the superword-level parallelism vectorization passes
-fsplit-dwarf-inlining	Unsupported	Provides minimal debug info in the object/executable to facilitate online symbolication/stack traces in the absence of .dwo/.dwp files when using Split DWARF
-fsplit-lto-unit	Unsupported	Enables splitting of the LTO unit
-fsplit-machine-functions	Supported	Enables late function splitting using profile information (x86 ELF)
-fstack-clash-protection	Supported	Enables stack clash protection
-fstack-protector-all	Unsupported	Enables stack protectors for all functions
-fstack-protector-strong	Unsupported	Enables stack protectors for some functions vulnerable to stack smashing. Compared to -fstack-protector, this uses a stronger heuristic that includes functions containing arrays of any size (and any type), as well as any calls to allocate or the taking of an address from a local variable.
-fstack-protector	Unsupported	Enables stack protectors for some functions vulnerable to stack smashing. This uses a loose heuristic that considers the functions to be vulnerable if they contain a char (or 8bit integer) array or constant-size calls to alloca, which are of greater size than ssp-buffer-size (default: 8 bytes). All variable-size calls to alloca are considered vulnerable. A function with a stack protector has a guard value added to the stack frame that is checked on function exit. The guard value must be positioned in the stack frame such that a buffer overflow from a vulnerable variable will overwrite the guard value before overwriting the function’s return address. The reference stack guard value is stored in a global variable.
-fstack-size-section	Supported	Emits section containing metadata on function stack sizes
-fstandalone-debug	Supported	Emits full debug info for all types used by the program
-fstrict-enums	Supported	Enables optimizations based on the strict definition of an enum’s value range
-fstrict-float-cast-overflow	Supported	Assumes the overflowing float-to-int casts to be undefined (default)
-fstrict-vtable-pointers	Supported	Enables optimizations based on the strict rules for overwriting polymorphic C++ objects
-fsycl	Unsupported	Enables SYCL kernels compilation for device
-fsystem-module	u	Builds this module as a system module. Only used with -emit-module
-fthin-link-bitcode= <value>	Supported	Writes minimized bitcode to <file> for the ThinLTO thin link only
-fthinlto-index= <value>	Unsupported	Performs ThinLTO import using the provided function summary index
-ftime-trace-granularity= <value>	Supported	Specifies the minimum time granularity (in microseconds) traced by time profiler
-ftime-trace	Supported	Turns on time profiler. Generates JSON file based on output filename
-ftrap-function= <value>	Unsupported	Issues call to specified function rather than a trap instruction
-ftrapv-handler= <function name>	Unsupported	Specifies the function to be called on overflow
-ftrapv	Supported	Traps on integer overflow
-ftrigraphs	Supported	Processes trigraph sequences
-ftrivial-auto-var-init-stop-after= <value>	Supported	Stops initializing trivial automatic stack variables after the specified number of instances
-ftrivial-auto-var-init= <value>	Supported	Initializes trivial automatic stack variables. Values: uninitialized (default) / pattern
-funique-basic-block-section-names	Supported	Uses unique names for basic block sections (ELF only)
-funique-internal-linkage-names	Supported	Makes the Internal Linkage Symbol names unique by appending the MD5 hash of the module path
-funroll-loops	Supported	Turns on loop unroller
-fuse-flang-math-libs	Supported	Uses Flang internal runtime math library instead of LLVM math intrinsics
-fuse-line-directives	Supported	Uses #line in preprocessed output
-fvalidate-ast-input-files-content	Supported	Computes and stores the hash of input files used to build an AST. Files with mismatching mtimes are considered valid if both have identical contents.
-fveclib= <value>	Unsupported	Uses the given vector functions library
-fvectorize	Unsupported	Enables the loop vectorization passes
-fverbose-asm	Supported	Generates verbose assembly output
-fvirtual-function-elimination	Supported	Enables dead virtual function elimination optimization. Requires -flto=full
-fvisibility-global-new-delete-hidden	Supported	Marks the visibility of global C++ operators “new” and “delete” as hidden
-fvisibility-inlines-hidden-static-local-var	Supported	Marks the visibility of static variables in inline C++ member functions as hidden by default when -fvisibility-inlines-hidden is enabled
-fvisibility-inlines-hidden	Supported	Marks the visibility of inline C++ member functions as hidden by default
-fvisibility-ms-compat	Supported	Marks the visibility of global types as default and global functions and variables as hidden by default
-fvisibility= <value>	Supported	Sets the default symbol visibility for all global declarations to the specified value
-fwasm-exceptions	Unsupported	Uses WebAssembly style exceptions
-fwhole-program-vtables	Unsupported	Enables whole program vtable optimization. Requires -flto
-fwrapv	Supported	Treats signed integer overflow as two’s complement
-fwritable-strings	Supported	Stores string literals as writable data
-fxray-always-emit-customevents	Unsupported	Mandates emitting __xray_customevent(…) calls even if the containing function is not always instrumented
-fxray-always-emit-typedevents	Unsupported	Mandates emitting __xray_typedevent(…) calls even if the containing function is not always instrumented
-fxray-always-instrument= <value>	Unsupported	Deprecated: Specifies the filename defining the whitelist for imbuing the “always instrument” XRay attribute
-fxray-attr-list= <value>	Unsupported	Specifies the filename defining the list of functions/types for imbuing XRay attributes
-fxray-ignore-loops	Unsupported	Prohibits instrumenting functions with loops unless they also meet the minimum function size
-fxray-instruction-threshold= <value>	Unsupported	Sets the minimum function size to instrument with Xray
-fxray-instrumentation-bundle= <value>	Unsupported	Specifies which XRay instrumentation points to emit. Values: all/ none/ function-entry/ function-exit/ function/ custom. Default is “all,” and “function” includes both “function-entry” and “function-exit.”
-fxray-instrument	Unsupported	Generates XRay instrumentation sleds on function entry and exit
-fxray-link-deps	Unsupported	Informs Clang to add the link dependencies for XRay
-fxray-modes= <value>	Unsupported	Specifies the list of modes to link in by default into the XRay instrumented binaries
-fxray-never-instrument= <value>	Unsupported	Deprecated: Specifies the filename defining the whitelist for imbuing the “never instrument” XRay attribute
-fzvector	Supported	Enables System z vector language extension
-F <value>	Unsupported	Adds directory to the framework include search path
–gcc-toolchain= <value>	Supported	Uses the gcc toolchain at the given directory
-gcodeview-ghash	Supported	Emits type record hashes in a .debug$H section
-gcodeview	Supported	Generates code view debug information
-gdwarf-2	Supported	Generates source-level debug information with dwarf version 2
-gdwarf-3	Supported	Generates source-level debug information with dwarf version 3
-gdwarf-4	Supported	Generates source-level debug information with dwarf version 4
-gdwarf-5	Supported	Generates source-level debug information with dwarf version 5
-gdwarf	Supported	Generates source-level debug information with the default DWARF version
-gembed-source	Supported	Embeds source text in DWARF debug sections
-gline-directives-only	Supported	Emits debug line info directives only.
-gline-tables-only	Supported	Emits debug line number tables only.
-gmodules	Supported	Generates debug info with external references to clang modules or precompiled headers
-gno-embed-source	Supported	Restores the default behavior of not embedding the source text in DWARF debug sections
-gno-inline-line-tables	Supported	Prohibits emitting inline line tables
–gpu-max-threads-per-block= <value>	Supported	Specifies the default max threads per block for kernel launch bounds for HIP
-gsplit-dwarf= <value>	Supported	Sets DWARF fission mode to values: “split”/ “single”
-gz= <value>	Supported	Specifies DWARF debug section’s compression type
-gz	Supported	Shows DWARF debug section”s compression type
-G <size>	Unsupported	Puts objects of maximum <size> bytes into small data section (MIPS / Hexagon)
-g	Supported	Generates source-level debug information
–help-hidden	Supported	Displays help for hidden options
-help	Supported	Displays available options
–hip-device-lib= <value>	Supported	Specifies the HIP device library
–hip-link	Supported	Links clang-offload-bundler bundles for HIP
–hip-version= <value>	Supported	Allows specification of HIP version in the format: major/minor/patch
-H	Supported	Shows header “includes” and nesting depth
-I-	Supported	Restricts all prior -I flags to double-quoted inclusion and removes the current directory from include path
-ibuiltininc	Supported	Enables built-in #include directories even when -nostdinc is used before or after -ibuiltininc. Using -nobuiltininc after the option disables it
-idirafter <value>	Supported	Adds the directory to AFTER include search path
-iframeworkwithsysroot <directory>	Unsupported	Adds the directory to SYSTEM framework search path; absolute paths are relative to -isysroot
-iframework <value>	Unsupported	Adds the directory to SYSTEM framework search path
-imacros <file>	Supported	Specifies the file containing macros to be included before parsing
-include-pch <file>	Supported	Includes the specified precompiled header file
-include <file>	Supported	Includes the specified file before parsing
-index-header-map	Supported	Makes the next included directory (-I or -F) an indexer header map
-iprefix <dir>	Supported	Sets the -iwithprefix/-iwithprefixbefore prefix
-iquote <directory>	Supported	Adds the directory to QUOTE include search path
-isysroot <dir>	Supported	Sets the system root directory (usually /)
-isystem-after <directory>	Supported	Adds the directory to end of the SYSTEM include search path
-isystem <directory>	Supported	Adds the directory to SYSTEM include search path
-ivfsoverlay <value>	Supported	Overlays the virtual file system described by the specified file over the real file system
-iwithprefixbefore <dir>	Supported	Sets the directory to include search path with prefix
-iwithprefix <dir>	Supported	Sets the directory to SYSTEM include search path with prefix
-iwithsysroot <directory>	Supported	Adds directory to SYSTEM include search path; absolute paths are relative to -isysroot
-I <dir>	Supported	Adds directory to include search path. If there are multiple -I options, these directories are searched in the order they are given before the standard system directories are searched. If the same directory is in the SYSTEM include search paths, for example, if also specified with -isystem, the -I option is ignored.
–libomptarget-nvptx-path= <value>	Unsupported	Specifies path to libomptarget-nvptx libraries
-L <dir>	Supported	Adds directory to library search path
-mabicalls	Unsupported	Enables SVR4-style position-independent code (Mips only)
-maix-struct-return	Unsupported	Returns all structs in memory (PPC32 only)
-malign-branch-boundary= <value>	Supported	Specifies the boundary’s size to align branches
-malign-branch= <value>	Supported	Specifies the types of branches to align
-malign-double	Supported	Aligns doubles to two words in structs (x86 only)
-Mallocatable= <value>	Unsupported	Provides semantics for assignments to allocatables. Value: F03/ F95.
-mbackchain	Unsupported	Links stack frames through backchain on System Z
-mbranch-protection= <value>	Unsupported	Enforces targets of indirect branches and function returns
-mbranches-within-32B-boundaries	Supported	Aligns selected branches (fused, jcc, jmp) within 32-byte boundary
-mcmodel=medany	Unsupported	Equivalent to -mcmodel=medium, compatible with RISC-V gcc
-mcmodel=medlow	Unsupported	Equivalent to -mcmodel=small, compatible with RISC-V gcc
-mcmse	Unsupported	Allows use of CMSE (Armv8-M Security Extensions)
-mcode-object-v3	Supported	Legacy option to specify code object ABI V2 (-mnocode-object-v3) or V3 (-mcode-object-v3) (AMDGPU only)
-mcode-object-version= <version>	Supported	Specifies code object ABI version. Default value: 4. (AMDGPU only).
-mcrc	Unsupported	Allows use of CRC instructions (ARM/Mips only)
-mcumode	Supported	Specifies CU (-mcumode) or WGP (-mno-cumode) wavefront execution mode (AMDGPU only)
-mdouble= <value>	Supported	Forces double to be 32 bits or 64 bits
-MD	Supported	Writes a depfile containing user and system headers
-meabi <value>	Supported	Sets EABI type. Value: 4/ 5/ gnu. Default depends on triple
-membedded-data	Unsupported	Places constants in the .rodata section instead of the .sdata section even if they meet the -G <size> threshold (MIPS)
-menable-experimental-extensions	Unsupported	Enables usage of experimental RISC-V extensions.
-mexec-model= <value>	Unsupported	Specifies the execution model (WebAssembly only)
-mexecute-only	Unsupported	Disallows generation of data access to code sections (ARM only)
-mextern-sdata	Unsupported	Assumes externally defined data to be in the small data if it meets the -G <size> threshold (MIPS)
-mfentry	Unsupported	Inserts calls to fentry at function entry (x86/SystemZ only)
-mfix-cortex-a53-835769	Unsupported	Workaround Cortex-A53 erratum 835769 (AArch64 only)
0	Unsupported	Asserts usage of 32-bit floating point registers (MIPS only)
0	Unsupported	Asserts usage of 64-bit floating point registers (MIPS only)
-MF <file>	Supported	Writes depfile output from -MMD, -MD, -MM, or -M to <file>
-mgeneral-regs-only	Unsupported	Generates code that exclusively uses the general-purpose registers (AArch64 only)
-mglobal-merge	Supported	Enables merging of globals
-mgpopt	Unsupported	Allows using GP relative accesses for symbols known to be in a small data section (MIPS)
-MG	Supported	Adds missing headers to depfile
-mharden-sls= <value>	Unsupported	Sets straight-line speculation hardening scope
-mhvx-length= <value>	Unsupported	Sets Hexagon Vector Length
-mhvx= <value>	Unsupported	Sets Hexagon Vector eXtensions
-mhvx	Unsupported	Enables Hexagon Vector eXtensions
-miamcu	Unsupported	Allows using Intel MCU ABI
–migrate	Unsupported	Runs the migrator
-mincremental-linker-compatible	Supported	(integrated-as) Emits an object file that can be used with an incremental linker
-mindirect-jump= <value>	Unsupported	Changes indirect jump instructions to inhibit speculation
-Minform= <value>	Supported	Sets error level of messages to display
-mios-version-min= <value>	Unsupported	Sets iOS deployment target
-MJ <value>	Unsupported	Writes a compilation database entry per input
-mllvm <value>	Supported	Specifies additional arguments to forward to LLVM’s option processing
-mlocal-sdata	Unsupported	Extends the -G behavior to object local data (MIPS)
-mlong-calls	Supported	Generates branches with extended addressability, usually via indirect jumps
-mlong-double-128	Supported on Host only	Forces long double to be 128 bits
-mlong-double-64	Supported	Forces long double to be 64 bits
-mlong-double-80	Supported on Host only	Forces long double to be 80 bits, padded to 128 bits for storage
-mlvi-cfi	Supported on Host only	Enables only control-flow mitigations for Load Value Injection (LVI)
-mlvi-hardening	Supported on Host only	Enables all mitigations for Load Value Injection (LVI)
-mmacosx-version-min= <value>	Unsupported	Sets Mac OS X deployment target
-mmadd4	Supported	Enables the generation of 4-operand madd.s, madd.d, and related instructions
-mmark-bti-property	Unsupported	Adds .note.gnu.property with BTI to assembly files (AArch64 only)
-MMD	Supported	Writes a depfile containing user headers
-mmemops	Supported	Enables generation of memop instructions
-mms-bitfields	Unsupported	Sets the default structure layout to be compatible with the Microsoft compiler standard
-mmsa	Unsupported	Enables MSA ASE (MIPS only)
-mmt	Unsupported	Enables MT ASE (MIPS only)
-MM	Supported	Similar to -MMD but also implies -E and writes to stdout by default
-mno-abicalls	Unsupported	Disables SVR4-style position-independent code (Mips only)
-mno-crc	Unsupported	Disallows use of CRC instructions (MIPS only)
-mno-embedded-data	Unsupported	Prohibits placing constants in the .rodata section instead of the .sdata if they meet the -G <size> threshold (MIPS)
-mno-execute-only	Unsupported	Allows generation of data access to code sections (ARM only)
-mno-extern-sdata	Unsupported	Prohibits assuming the externally defined data to be in the small data if it meets the -G <size> threshold (MIPS)
-mno-fix-cortex-a53-835769	Unsupported	Disallows workaround Cortex-A53 erratum 835769 (AArch64 only)
-mno-global-merge	Supported	Disables merging of globals
-mno-gpopt	Unsupported	Prohibits using GP relative accesses for symbols known to be in a small data section (MIPS)
-mno-hvx	Unsupported	Disables Hexagon Vector eXtensions.
-mno-implicit-float	Supported	Prohibits generating implicit floating-point instructions
-mno-incremental-linker-compatible	Supported	(integrated-as) Emits an object file that cannot be used with an incremental linker
-mno-local-sdata	Unsupported	Prohibits extending the -G behavior to object local data (MIPS)
-mno-long-calls	Supported	Restores the default behavior of not generating long calls
-mno-lvi-cfi	Supported on Host only	Disables control-flow mitigations for Load Value Injection (LVI)
-mno-lvi-hardening	Supported on Host only	Disables mitigations for Load Value Injection (LVI)
-mno-madd4	Supported	Disables the generation of 4-operand madd.s, madd.d, and related instructions
-mno-memops	Supported	Disables the generation of memop instructions
-mno-movt	Supported	Disallows usage of movt/movw pairs (ARM only)
-mno-ms-bitfields	Supported	Prohibits setting the default structure layout to be compatible with the Microsoft compiler standard
-mno-msa	Unsupported	Disables MSA ASE (MIPS only)
-mno-mt	Unsupported	Disables MT ASE (MIPS only)
-mno-neg-immediates	Supported	Disallows converting instructions with negative immediates to their negation or inversion
-mno-nvj	Supported	Disables generation of new-value jumps
-mno-nvs	Supported	Disables generation of new-value stores
-mno-outline	Unsupported	Disables function outlining (AArch64 only)
-mno-packets	Supported	Disables generation of instruction packets
-mno-relax	Supported	Disables linker relaxation
-mno-restrict-it	Unsupported	Allows generation of deprecated IT blocks for ARMv8. It is off by default for ARMv8 Thumb mode
-mno-save-restore	Unsupported	Disables usage of library calls for save and restore
-mno-seses	Unsupported	Disables speculative execution side-effect suppression (SESES)
-mno-stack-arg-probe	Supported	Disables stack probes which are enabled by default
-mno-tls-direct-seg-refs	Supported	Disables direct TLS access through segment registers
-mno-unaligned-access	Unsupported	Forces all memory accesses to be aligned (AArch32/AArch64 only)
-mno-wavefrontsize64	Supported	Asserts wavefront size to 32 (AMDGPU only)
-mnocrc	Unsupported	Disallows usage of CRC instructions (ARM only)
-mnop-mcount	Supported	Generates mcount/__fentry__ calls as nops. To activate, they need to be patched in
-mnvj	Supported	Enables generation of new-value jumps
-mnvs	Supported	Enables generation of new-value stores
-module-dependency-dir <value>	Unsupported	Specifies directory for dumping module dependencies
-module-file-info	Unsupported	Provides information about a particular module file
-momit-leaf-frame-pointer	Supported	Omits frame pointer setup for leaf functions
-moutline	Unsupported	Enables function outlining (AArch64 only)
-mpacked-stack	Unsupported	Asserts the usage of packed stack layout (SystemZ only)
-mpackets	Supported	Enables generation of instruction packets
-mpad-max-prefix-size= <value>	Supported	Specifies maximum number of prefixes to use for padding
-mpie-copy-relocations	Supported	Asserts the usage of copy relocations support for PIE builds
-mprefer-vector-width= <value>	Unsupported	Specifies preferred vector width for auto-vectorization. Default value: “none,” which allows target specific decisions.
-MP	Supported	Creates phony target for each dependency (other than the main file)
-mqdsp6-compat	Unsupported	Enables hexagon-qdsp6 backward compatibility
-MQ <value>	Supported	Specifies the name of the main file output to quote in depfile
-mrecord-mcount	Supported	Generates a __mcount_loc section entry for each fentry call
-mrelax-all	Supported	(integrated-as) Relaxes all machine instructions
-mrelax	Supported	Enables linker relaxation
-mrestrict-it	Unsupported	Disallows generation of deprecated IT blocks for ARMv8. It is on by default for ARMv8 Thumb mode.
-mrtd	Unsupported	Makes StdCall calling the default convention
-msave-restore	Unsupported	Enables using library calls for save and restore
-mseses	Unsupported	Enables speculative execution side effect suppression (SESES). Includes LVI control flow integrity mitigations.
-msign-return-address= <value>	Unsupported	Specifies the return address signing scope
-msmall-data-limit= <value>	Supported	Puts global and static data smaller than the specified limit into a special section
-msoft-float	Supported	Uses software floating point
-msram-ecc	Supported	Legacy option to specify SRAM ECC mode (AMDGPU only). Should use –offload-arch with sramecc+ instead.
-mstack-alignment= <value>	Unsupported	Sets the stack alignment
-mstack-arg-probe	Unsupported	Enables stack probes
-mstack-probe-size= <value>	Unsupported	Sets the stack probe size
-mstackrealign	Unsupported	Forces realign the stack at entry on every function
-msve-vector-bits= <value>	Unsupported	Specifies the size in bits of an SVE vector register. Defaults to the vector length agnostic value of “scalable” (AArch64 only).
-msvr4-struct-return	Unsupported	Returns small structs in registers (PPC32 only)
-mthread-model <value>	Supported	Specifies the thread model to use. Value: posix/single. Default: posix.
-mtls-direct-seg-refs	Supported	Enables direct TLS access through segment registers (default)
-mtls-size= <value>	Unsupported	Specifies the bit size of immediate TLS offsets (AArch64 ELF only). Value: 12 (for 4KB) \ 24 (for 16MB, default) \ 32 (for 4GB) \ 48 (for 256TB, needs -mcmodel=large).
-mtp= <value>	Unsupported	Specifies the thread pointer access method. Value: AArch32/AArch64 only
-mtune= <value>	Supported on Host only	Supported on X86 only. Otherwise accepted for compatibility with GCC.
-MT <value>	Unsupported	Specifies the name of main file output in depfile
-munaligned-access	Unsupported	Allows memory accesses to be unaligned (AArch32/AArch64 only)
-MV	Supported	Uses NMake/Jom format for the depfile
-mwavefrontsize64	Supported	Asserts wavefront size of 64 (AMDGPU only)
-mxnack	Supported	Legacy option to specify XNACK mode (AMDGPU only). Use –offload-arch with :xnack+ instead.
-M	Supported	Similar to -MD but also implies -E and writes to stdout by default
–no-cuda-include-ptx= <value>	Supported	Prohibits including PTX for the specified GPU architecture (e.g. sm_35) or “all”. May be specified more than once.
–no-cuda-version-check	Supported	Disallows erroring out if the detected version of the CUDA install is too low for the requested CUDA GPU architecture
-no-flang-libs	Supported	Prohibits linking against Flang libraries
–no-offload-arch= <value>	Supported	Removes CUDA/HIP offloading device architecture (e.g. sm_35, gfx906) from the list of devices to compile for. “all” resets the list to its default value
–no-system-header-prefix= <prefix>	Supported	Assumes no system header for all #include paths starting with the given <prefix>
-nobuiltininc	Supported	Disables built-in #include directories
-nogpuinc	Supported	Prohibits adding CUDA/HIP include paths and includes default CUDA/HIP wrapper header files
-nogpulib	Supported	Prohibits linking device library for CUDA/HIP device compilation
-nostdinc++	Unsupported	Disables standard #include directories for the C++ standard library
-ObjC++	Unsupported	Treats source input files as Objective-C++ inputs
-objcmt-atomic-property	Unsupported	Enables migration to “atomic” properties
-objcmt-migrate-all	Unsupported	Enables migration to modern ObjC
-objcmt-migrate-annotation	Unsupported	Enables migration to property and method annotations
-objcmt-migrate-designated-init	Unsupported	Enables migration to infer NS_DESIGNATED_INITIALIZER for initializer methods
-objcmt-migrate-instancetype	Unsupported	Enables migration to infer instancetype for method result type
-objcmt-migrate-literals	Unsupported	Enables migration to modern ObjC literals
-objcmt-migrate-ns-macros	Unsupported	Enables migration to NS_ENUM/NS_OPTIONS macros
-objcmt-migrate-property-dot-syntax	Unsupported	Enables migration of setter/getter messages to property-dot syntax
-objcmt-migrate-property	Unsupported	Enables migration to modern ObjC property
-objcmt-migrate-protocol-conformance	Unsupported	Enables migration to add protocol conformance on classes
-objcmt-migrate-readonly-property	Unsupported	Enables migration to modern ObjC readonly property
-objcmt-migrate-readwrite-property	Unsupported	Enables migration to modern ObjC readwrite property
-objcmt-migrate-subscripting	Unsupported	Enables migration to modern ObjC subscripting
-objcmt-ns-nonatomic-iosonly	Unsupported	Enables migration to use NS_NONATOMIC_IOSONLY macro for setting property’s “atomic” attribute
-objcmt-returns-innerpointer-property	Unsupported	Enables migration to annotate property with NS_RETURNS_INNER_POINTER
-objcmt-whitelist-dir-path= <value>	Unsupported	Modifies exclusively the files with the filename present in the given directory
-ObjC	Unsupported	Treats source input files as Objective-C inputs
–offload-arch= <value>	Supported	Specifies CUDA offloading device architecture (e.g. sm_35), or HIP offloading target ID in the form of a device architecture followed by target ID features delimited by a colon. Each target ID feature is a predefined string followed by a plus or minus sign (e.g. gfx908:xnack+:sramecc-). May be specified more than once.
-o <file>	Supported	Writes output to the given <file>
-parallel-jobs= <value>	Supported	Specifies the number of parallel jobs allowed
-pg	Supported	Enables mcount instrumentation
-pipe	Supported	Asserts using pipes between commands, when possible.
–precompile	Supported	Only precompiles the input
-print-effective-triple	Supported	Prints the effective target triple
-print-file-name= <file>	Supported	Prints the full library path of the given <file>
-print-ivar-layout	Unsupported	Enables Objective-C Ivar layout bitmap print trace
-print-libgcc-file-name	Supported	“Prints the library path for the currently used compiler runtime library (“”libgcc.a”” or “”libclang_rt.builtins.*.a””)”
-print-prog-name= <name>	Supported	Prints the full program path of the given <name>
-print-resource-dir	Supported	Prints the resource directory pathname
-print-search-dirs	Supported	Prints the paths used for finding libraries and programs
-print-supported-cpus	Supported	Prints the supported CPU models for the given target. If target is not specified, it prints the supported CPUs for the default target.
-print-target-triple	Supported	Prints the normalized target triple
-print-targets	Supported	Prints the registered targets
-pthread	Supported	Supports POSIX threads in the generated code
–ptxas-path= <value>	Unsupported	Specifies the path to ptxas (used for compiling CUDA code)
-P	Supported	Disables linemarker output in -E mode
-Qn	Supported	Prohibits emitting metadata containing compiler name and version
-Qunused-arguments	Supported	Prohibits emitting warning for unused driver arguments
-Qy	Supported	Emits metadata containing compiler name and version
-relocatable-pch	Supported	Allows to build a relocatable precompiled header
-rewrite-legacy-objc	Unsupported	Rewrites Legacy Objective-C source to C++
-rewrite-objc	Unsupported	Rewrites Objective-C source to C++
–rocm-device-lib-path= <value>	Supported	Specifies ROCm device library path. Alternative to rocm-path
–rocm-path= <value>	Supported	Specifies ROCm installation path that is used for finding and automatically linking required bitcode libraries
-Rpass-analysis= <value>	Supported	Reports transformation analysis by optimization passes whose names match the given POSIX regular expression
-Rpass-missed= <value>	Supported	Reports missed transformations by optimization passes whose names match the given POSIX regular expression
-Rpass= <value>	Supported	Reports transformations by optimization passes whose names match the given POSIX regular expression
-rtlib= <value>	Unsupported	Specifies the compiler runtime library to be used
-R <remark>	Unsupported	Enables the specified remark
-save-stats= <value>	Supported	Saves llvm statistics
-save-stats	Supported	Saves llvm statistics
-save-temps= <value>	Supported	Saves intermediate compilation results
-save-temps	Supported	Saves intermediate compilation results
-serialize-diagnostics= <value>	Supported	Serializes compiler diagnostics to the specified file
-shared-libsan	Unsupported	Dynamically links the sanitizer runtime
-static-flang-libs	Supported	Asserts linking using static Flang libraries
-static-libsan	Unsupported	Statically links the sanitizer runtime
-static-openmp	Supported	Asserts using the static host OpenMP runtime while linking
-std= <value>	Supported	Specifies the language standard to compile for.
-stdlib+±isystem <directory>	Supported	Specifies the directory to be used as the C++ standard library include path
-stdlib= <value>	Supported	Specifies the C++ standard library to be used
-sycl-std= <value>	Unsupported	Specifies the SYCL language standard to compile for
–system-header-prefix= <prefix>	Supported	Assumes all #include paths starting with the given <prefix> to include a system header
-S	Supported	Runs only preprocess and compilation steps
–target= <value>	Supported	Generates code for the given target
-Tbss <addr>	Supported	Sets the starting address of BSS to the given <addr>
-Tdata <addr>	Supported	Sets the starting address of DATA to the given <addr>
-time	Supported	Times individual commands
-traditional-cpp	Unsupported	Enables some traditional CPP emulation
-trigraphs	Supported	Processes trigraph sequences
-Ttext <addr>	Supported	Sets starting address of TEXT to the given <addr>
-T \ <script\>	Unsupported	Specifies the given. \ <script\> as linker script
-undef	Supported	undefs all system defines
-unwindlib= <value>	Supported	Specifies the unwind library to be used
-U <macro>	Supported	Undefines the given <macro>
–verify-debug-info	Supported	Verifies the binary representation of the debug output
-verify-pch	Unsupported	Loads and verifies if a precompiled header file is stale
–version	Supported	Prints version information
-v	Supported	Shows commands to be run, and uses verbose output
-Wa, <arg>	Supported	Passes the comma-separated arguments in the given <arg> to the assembler
-Wdeprecated	Supported	Enables warnings for deprecated constructs and defines_DEPRECATED
-Wl, <arg>	Supported	Passes comma-separated arguments in <arg> to the linker.
-working-directory <value>	Supported	Resolves file paths relative to the specified directory
-Wp, <arg>	Supported	Passes comma-separated arguments in <arg> to the preprocessor
-W <warning>	Supported	Enables the specified warning
-w	Supported	Suppresses all warnings
-Xanalyzer <arg>	Supported	Passes <arg> to the static analyzer
-Xarch_device <arg>	Supported	Passes <arg> to the CUDA/HIP device compilation
-Xarch_host <arg>	Supported	Passes <arg> to the CUDA/HIP host compilation
-Xassembler <arg>	Supported	Passes <arg> to the assembler
-Xclang <arg>	Supported	Passes <arg> to the clang compiler
-Xcuda-fatbinary <arg>	Supported	Passes <arg> to fatbinary invocation
-Xcuda-ptxas <arg>	Supported	Passes <arg> to the ptxas assembler
-Xlinker <arg>	Supported	Passes <arg> to the linker
-Xopenmp-target= <triple> <arg>	Supported	Passes <arg> to the target offloading toolchain identified by <triple>
-Xopenmp-target <arg>	Supported	Passes <arg> to the target offloading toolchain
-Xpreprocessor <arg>	Supported	Passes <arg> to the preprocessor
-x <language>	Supported	Assumes subsequent input files to have the given type <language>
-z <arg>	Supported	Passes -z <arg> to the linker