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[X86][APX] Check APXSave before enabling APX features (#172834)

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According to APX spec 3.1.4.2, APX instructions can normally execute
only when XCR0[APX_F]=1, where APX_F=19.
This commit is contained in:
Phoebe Wang 2025-12-18 22:22:20 +08:00 committed by GitHub
parent 492ca62e2c
commit d6c2cd69cb
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GPG Key ID: B5690EEEBB952194
2 changed files with 5 additions and 2 deletions
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3
compiler-rt/lib/builtins/cpu_model/x86.c
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@ -926,6 +926,7 @@ static void getAvailableFeatures(unsigned ECX, unsigned EDX, unsigned MaxLeaf,
const unsigned AMXBits = (1 << 17) | (1 << 18);
bool HasXSave = ((ECX >> 27) & 1) && !getX86XCR0(&EAX, &EDX);
bool HasAMXSave = HasXSave && ((EAX & AMXBits) == AMXBits);
bool HasAPXSave = HasXSave && ((EAX >> 19) & 1);
if (HasAVXSave)
setFeature(FEATURE_AVX);
@ -1065,7 +1066,7 @@ static void getAvailableFeatures(unsigned ECX, unsigned EDX, unsigned MaxLeaf,
setFeature(FEATURE_PREFETCHI);
if (HasLeaf7Subleaf1 && ((EDX >> 15) & 1))
setFeature(FEATURE_USERMSR);
if (HasLeaf7Subleaf1 && ((EDX >> 21) & 1))
if (HasLeaf7Subleaf1 && ((EDX >> 21) & 1) && HasAPXSave)
setFeature(FEATURE_APXF);
unsigned MaxLevel = 0;

4
llvm/lib/TargetParser/Host.cpp
View File

@ -2040,6 +2040,8 @@ StringMap<bool> sys::getHostCPUFeatures() {
// AMX requires additional context to be saved by the OS.
const unsigned AMXBits = (1 << 17) | (1 << 18);
bool HasAMXSave = HasXSave && ((EAX & AMXBits) == AMXBits);
// APX requires additional context to be saved by the OS.
bool HasAPXSave = HasXSave && ((EAX >> 19) & 1);
Features["avx"] = HasAVXSave;
Features["fma"] = ((ECX >> 12) & 1) && HasAVXSave;
@ -2162,7 +2164,7 @@ StringMap<bool> sys::getHostCPUFeatures() {
Features["prefetchi"] |= HasLeaf7Subleaf1 && ((EDX >> 14) & 1);
Features["usermsr"] = HasLeaf7Subleaf1 && ((EDX >> 15) & 1);
bool HasAVX10 = HasLeaf7Subleaf1 && ((EDX >> 19) & 1);
bool HasAPXF = HasLeaf7Subleaf1 && ((EDX >> 21) & 1);
bool HasAPXF = HasLeaf7Subleaf1 && ((EDX >> 21) & 1) && HasAPXSave;
Features["egpr"] = HasAPXF;
Features["push2pop2"] = HasAPXF;
Features["ppx"] = HasAPXF;