[llvm] [AArch64] Improve host feature detection. (PR #160410)
Daniel Paoliello via llvm-commits
llvm-commits at lists.llvm.org
Thu Sep 25 09:02:42 PDT 2025
dpaoliello wrote:
Before the patch:
```
> .\build\bin\clang.exe -mcpu=native -print-enabled-extensions
clang version 22.0.0git (https://github.com/dpaoliello/llvm-project.git d136fbdf8cf626a446cc53345810d3f59b7e433c)
Target: aarch64-pc-windows-msvc
Thread model: posix
InstalledDir: C:\repos\llvm\build\bin
Build config: +assertions
Extensions enabled for the given AArch64 target
Architecture Feature(s) Description
FEAT_AES, FEAT_PMULL Enable AES support
FEAT_AMUv1 Enable Armv8.4-A Activity Monitors extension
FEAT_AMUv1p1 Enable Armv8.6-A Activity Monitors Virtualization support
FEAT_AdvSIMD Enable Advanced SIMD instructions
FEAT_BF16 Enable BFloat16 Extension
FEAT_BTI Enable Branch Target Identification
FEAT_CCIDX Enable Armv8.3-A Extend of the CCSIDR number of sets
FEAT_CRC32 Enable Armv8.0-A CRC-32 checksum instructions
FEAT_CSV2_2 Enable architectural speculation restriction
FEAT_DIT Enable Armv8.4-A Data Independent Timing instructions
FEAT_DPB Enable Armv8.2-A data Cache Clean to Point of Persistence
FEAT_DPB2 Enable Armv8.5-A Cache Clean to Point of Deep Persistence
FEAT_DotProd Enable dot product support
FEAT_ECV Enable enhanced counter virtualization extension
FEAT_FCMA Enable Armv8.3-A Floating-point complex number support
FEAT_FGT Enable fine grained virtualization traps extension
FEAT_FHM Enable FP16 FML instructions
FEAT_FP Enable Armv8.0-A Floating Point Extensions
FEAT_FP16 Enable half-precision floating-point data processing
FEAT_FRINTTS Enable FRInt[32|64][Z|X] instructions that round a floating-point number to an integer (in FP format) forcing it to fit into a 32- or 64-bit int
FEAT_FlagM Enable Armv8.4-A Flag Manipulation instructions
FEAT_FlagM2 Enable alternative NZCV format for floating point comparisons
FEAT_I8MM Enable Matrix Multiply Int8 Extension
FEAT_JSCVT Enable Armv8.3-A JavaScript FP conversion instructions
FEAT_LOR Enable Armv8.1-A Limited Ordering Regions extension
FEAT_LRCPC Enable support for RCPC extension
FEAT_LRCPC2 Enable Armv8.4-A RCPC instructions with Immediate Offsets
FEAT_LSE Enable Armv8.1-A Large System Extension (LSE) atomic instructions
FEAT_LSE2 Enable Armv8.4-A Large System Extension 2 (LSE2) atomicity rules
FEAT_MPAM Enable Armv8.4-A Memory system Partitioning and Monitoring extension
FEAT_NV, FEAT_NV2 Enable Armv8.4-A Nested Virtualization Enchancement
FEAT_PAN Enable Armv8.1-A Privileged Access-Never extension
FEAT_PAN2 Enable Armv8.2-A PAN s1e1R and s1e1W Variants
FEAT_PAuth Enable Armv8.3-A Pointer Authentication extension
FEAT_PMUv3 Enable Armv8.0-A PMUv3 Performance Monitors extension
FEAT_RAS, FEAT_RASv1p1 Enable Armv8.0-A Reliability, Availability and Serviceability Extensions
FEAT_RDM Enable Armv8.1-A Rounding Double Multiply Add/Subtract instructions
FEAT_RNG Enable Random Number generation instructions
FEAT_SB Enable Armv8.5-A Speculation Barrier
FEAT_SEL2 Enable Armv8.4-A Secure Exception Level 2 extension
FEAT_SHA1, FEAT_SHA256 Enable SHA1 and SHA256 support
FEAT_SHA3, FEAT_SHA512 Enable SHA512 and SHA3 support
FEAT_SM4, FEAT_SM3 Enable SM3 and SM4 support
FEAT_SPE Enable Statistical Profiling extension
FEAT_SPECRES Enable Armv8.5-A execution and data prediction invalidation instructions
FEAT_SSBS, FEAT_SSBS2 Enable Speculative Store Bypass Safe bit
FEAT_TLBIOS, FEAT_TLBIRANGE Enable Armv8.4-A TLB Range and Maintenance instructions
FEAT_TRF Enable Armv8.4-A Trace extension
FEAT_UAO Enable Armv8.2-A UAO PState
FEAT_VHE Enable Armv8.1-A Virtual Host extension
> .\build\bin\clang.exe -mcpu=native -### empty.c -c -nostdinc
clang version 22.0.0git (https://github.com/dpaoliello/llvm-project.git d136fbdf8cf626a446cc53345810d3f59b7e433c)
Target: aarch64-pc-windows-msvc
Thread model: posix
InstalledDir: C:\repos\llvm\build\bin
Build config: +assertions
(in-process)
"C:\\repos\\llvm\\build\\bin\\clang.exe" "-cc1" "-triple" "aarch64-pc-windows-msvc19.44.35213" "-emit-obj" "-mincremental-linker-compatible" "-disable-free" "-clear-ast-before-backend" "-main-file-name" "empty.c" "-mrelocation-model" "pic" "-pic-level" "2" "-mframe-pointer=reserved" "-relaxed-aliasing" "-fmath-errno" "-ffp-contract=on" "-fno-rounding-math" "-mconstructor-aliases" "-funwind-tables=2" "-enable-tlsdesc" "-target-cpu" "oryon-1" "-target-feature" "+v8.6a" "-target-feature" "+aes" "-target-feature" "+bf16" "-target-feature" "+ccidx" "-target-feature" "+complxnum" "-target-feature" "+crc" "-target-feature" "+dotprod" "-target-feature" "+fp-armv8" "-target-feature" "+i8mm" "-target-feature" "+jsconv" "-target-feature" "+lse" "-target-feature" "+neon" "-target-feature" "+pauth" "-target-feature" "+perfmon" "-target-feature" "+rand" "-target-feature" "+ras" "-target-feature" "+rcpc" "-target-feature" "+rdm" "-target-feature" "+sha2" "-target-feature" "+sha3" "-target-feature" "+sm4" "-target-feature" "+spe" "-target-feature" "+ssbs" "-target-abi" "aapcs" "-fdebug-compilation-dir=C:\\repos\\llvm" "-fcoverage-compilation-dir=C:\\repos\\llvm" "-nostdsysteminc" "-nobuiltininc" "-resource-dir" "C:\\repos\\llvm\\build\\lib\\clang\\22" "-ferror-limit" "19" "-fmessage-length=120" "-fno-use-cxa-atexit" "-fms-extensions" "-fms-compatibility" "-fms-compatibility-version=19.44.35213" "-fskip-odr-check-in-gmf" "-fdelayed-template-parsing" "-fcolor-diagnostics" "-target-feature" "-fmv" "-faddrsig" "-o" "empty.o" "-x" "c" "empty.c"
```
Looks like the patch adds the following target feature args:
```
-sve-sm4
-sve2
-sve-sha3
-sve
+jscvt
-f32mm
-sve-aes
-f64mm
```
https://github.com/llvm/llvm-project/pull/160410
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