MaskRay added inline comments.
================
Comment at: clang/lib/CodeGen/CGBuiltin.cpp:13272
+ uint64_t Mask = llvm::X86::getCpuSupportsMask(FeatureStrs);
+ uint32_t FeaturesMask[4] = {uint32_t(Mask), uint32_t(Mask >> 32), 0, 0};
+ return EmitX86CpuSupports(FeaturesMask);
----------------
pengfei wrote:
> Use `Lo_32(Mask)`, `Hi_32(Mask)`?
Lo_32/Hi_32 are currently unused in clang/. Using this needs MathExtras.h. I am
unsure it's worthwhile..
================
Comment at: clang/lib/CodeGen/CGBuiltin.cpp:13318-13320
+ Value *Idxs[] = {Builder.getInt32(0), Builder.getInt32(i - 1)};
+ Value *Features = Builder.CreateAlignedLoad(
+ Int32Ty, Builder.CreateGEP(ATy, CpuFeatures2, Idxs),
----------------
pengfei wrote:
> Do we have problem when linking with old version of libgcc?
If we don't use `__cpu_features2[1..3]`, no problem with older libgcc.
The way GCC upgraded `__cpu_features2` to an array is compatible with scalar
`__cpu_features2`.
================
Comment at: compiler-rt/lib/builtins/cpu_model.c:808
+ if (HasExtLeaf1) {
+ if (ECX & 1)
+ setFeature(FEATURE_LAHF_LM);
----------------
pengfei wrote:
> pengfei wrote:
> > Can we reuse bit defination in cpuid.h, e.g., `if (ECX & bit_LAHF_LM)`? The
> > same below.
> Can we reuse bit defination in cpuid.h, e.g., `if (ECX & bit_LAHF_LM)`? The
> same below.
Thanks for the cpuid.h idea, but I think likely no. MSVC does not provide
cpuid.h. It would be nice if we don't allow MSVC to build the file (we can say
that `LLVM_ENABLE_PROJECTS='...compiler-rt'` is not allowed and
LLVM_ENABLE_RUNTIMES or Clang should be used, but I think we are not there yet).
Unfortunately I am also unsure whether anyone uses MSVC to build this file, but
there are Windows related macros like `FIXME: For MSVC, we should make a
function pointer global in` in this file...
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D158329/new/
https://reviews.llvm.org/D158329
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
