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| author | Wei Mi <wmi@google.com> | 2018-01-23 23:27:57 +0000 |
|---|---|---|
| committer | Wei Mi <wmi@google.com> | 2018-01-23 23:27:57 +0000 |
| commit | d1621699dc38611fbab364129fabc3d5589a8eae (patch) | |
| tree | fa8b5894bc78fc9c009593d5d43b31711876cee0 /clang/lib/Basic | |
| parent | 4386bc5a60f77acea456e6e497e8ff63c1a79369 (diff) | |
| download | bcm5719-llvm-d1621699dc38611fbab364129fabc3d5589a8eae.tar.gz bcm5719-llvm-d1621699dc38611fbab364129fabc3d5589a8eae.zip | |
Adjust MaxAtomicInlineWidth for i386/i486 targets.
This is to fix the bug reported in https://bugs.llvm.org/show_bug.cgi?id=34347#c6.
Currently, all MaxAtomicInlineWidth of x86-32 targets are set to 64. However,
i386 doesn't support any cmpxchg related instructions. i486 only supports cmpxchg.
So in this patch MaxAtomicInlineWidth is reset as follows:
For i386, the MaxAtomicInlineWidth should be 0 because no cmpxchg is supported.
For i486, the MaxAtomicInlineWidth should be 32 because it supports cmpxchg.
For others 32 bits x86 cpu, the MaxAtomicInlineWidth should be 64 because of cmpxchg8b.
Differential Revision: https://reviews.llvm.org/D42154
llvm-svn: 323281
Diffstat (limited to 'clang/lib/Basic')
| -rw-r--r-- | clang/lib/Basic/Targets/X86.h | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/clang/lib/Basic/Targets/X86.h b/clang/lib/Basic/Targets/X86.h index 836cc681639..abe10017ca2 100644 --- a/clang/lib/Basic/Targets/X86.h +++ b/clang/lib/Basic/Targets/X86.h @@ -100,6 +100,7 @@ class LLVM_LIBRARY_VISIBILITY X86TargetInfo : public TargetInfo { bool HasRetpoline = false; bool HasRetpolineExternalThunk = false; +protected: /// \brief Enumeration of all of the X86 CPUs supported by Clang. /// /// Each enumeration represents a particular CPU supported by Clang. These @@ -325,9 +326,11 @@ public: (1 << TargetInfo::LongDouble)); // x86-32 has atomics up to 8 bytes - // FIXME: Check that we actually have cmpxchg8b before setting - // MaxAtomicInlineWidth. (cmpxchg8b is an i586 instruction.) - MaxAtomicPromoteWidth = MaxAtomicInlineWidth = 64; + CPUKind Kind = getCPUKind(Opts.CPU); + if (Kind >= CK_i586 || Kind == CK_Generic) + MaxAtomicPromoteWidth = MaxAtomicInlineWidth = 64; + else if (Kind >= CK_i486) + MaxAtomicPromoteWidth = MaxAtomicInlineWidth = 32; } BuiltinVaListKind getBuiltinVaListKind() const override { |
