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8371432: [BACKOUT] 8359256: AArch64: Use SHA3 GPR intrinsic where it's faster

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Reviewed-by: mchevalier, epeter, syan
This commit is contained in:
Tobias Hartmann 2025-11-07 09:19:18 +00:00
parent 48bbc950f1
commit 3d6824e802
2 changed files with 13 additions and 19 deletions
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2
src/hotspot/cpu/aarch64/globals_aarch64.hpp
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@ -95,7 +95,7 @@ define_pd_global(intx, InlineSmallCode, 1000);
"Use simplest and shortest implementation for array equals") \
product(bool, UseSIMDForBigIntegerShiftIntrinsics, true, \
"Use SIMD instructions for left/right shift of BigInteger") \
product(bool, UseSIMDForSHA3Intrinsic, false, \
product(bool, UseSIMDForSHA3Intrinsic, true, \
"Use SIMD SHA3 instructions for SHA3 intrinsic") \
product(bool, AvoidUnalignedAccesses, false, \
"Avoid generating unaligned memory accesses") \

30
src/hotspot/cpu/aarch64/vm_version_aarch64.cpp
View File

@ -375,24 +375,18 @@ void VM_Version::initialize() {
FLAG_SET_DEFAULT(UseSHA256Intrinsics, false);
}
if (UseSHA && VM_Version::supports_sha3() && _cpu == CPU_APPLE && FLAG_IS_DEFAULT(UseSIMDForSHA3Intrinsic)) {
// Note: SIMD faster on Apple, worse on Neoverse V1, V2 and N2.
FLAG_SET_DEFAULT(UseSIMDForSHA3Intrinsic, true);
}
// Enable SHA-3 intrinsics (SIMD or GPR). The GPR path does not require SHA instructions.
if (FLAG_IS_DEFAULT(UseSHA3Intrinsics)) {
FLAG_SET_DEFAULT(UseSHA3Intrinsics, true);
}
if (!UseSHA3Intrinsics && UseSIMDForSHA3Intrinsic) {
// Keep flags consistent: if SHA3 intrinsics are off, disable the SHA3 SIMD variant.
FLAG_SET_DEFAULT(UseSIMDForSHA3Intrinsic, false);
}
if (!VM_Version::supports_sha3() && UseSIMDForSHA3Intrinsic) {
warning("SHA3 instructions are not available on this CPU");
FLAG_SET_DEFAULT(UseSIMDForSHA3Intrinsic, false);
if (UseSHA && VM_Version::supports_sha3()) {
// Auto-enable UseSHA3Intrinsics on hardware with performance benefit.
// Note that the evaluation of UseSHA3Intrinsics shows better performance
// on Apple silicon but worse performance on Neoverse V1 and N2.
if (_cpu == CPU_APPLE) { // Apple silicon
if (FLAG_IS_DEFAULT(UseSHA3Intrinsics)) {
FLAG_SET_DEFAULT(UseSHA3Intrinsics, true);
}
}
} else if (UseSHA3Intrinsics && UseSIMDForSHA3Intrinsic) {
warning("Intrinsics for SHA3-224, SHA3-256, SHA3-384 and SHA3-512 crypto hash functions not available on this CPU.");
FLAG_SET_DEFAULT(UseSHA3Intrinsics, false);
}
if (UseSHA && VM_Version::supports_sha512()) {