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author | Dan Gohman <gohman@apple.com> | 2009-09-15 00:14:11 +0000 |
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committer | Dan Gohman <gohman@apple.com> | 2009-09-15 00:14:11 +0000 |
commit | 907355caf89549138ab3ea0e4ab13a5df0ee014a (patch) | |
tree | b56c5968a255a1e06ade7332652715c2fcbee3f6 /lib | |
parent | e6798372ea38e5ea24c26282a0d69aa6e3829854 (diff) | |
download | llvm-907355caf89549138ab3ea0e4ab13a5df0ee014a.tar.gz llvm-907355caf89549138ab3ea0e4ab13a5df0ee014a.tar.bz2 llvm-907355caf89549138ab3ea0e4ab13a5df0ee014a.tar.xz |
On x86-64, the 32-bit cmov doesn't actually clear the high 32-bit of
its result if the condition is false.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@81814 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
-rw-r--r-- | lib/Target/X86/X86Instr64bit.td | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/lib/Target/X86/X86Instr64bit.td b/lib/Target/X86/X86Instr64bit.td index 353868a407..ac90357038 100644 --- a/lib/Target/X86/X86Instr64bit.td +++ b/lib/Target/X86/X86Instr64bit.td @@ -387,13 +387,15 @@ def MOVZX64rm32 : I<0x8B, MRMSrcMem, (outs GR64:$dst), (ins i32mem:$src), [(set GR64:$dst, (zextloadi64i32 addr:$src))]>; // Any instruction that defines a 32-bit result leaves the high half of the -// register. Truncate can be lowered to EXTRACT_SUBREG, and CopyFromReg may -// be copying from a truncate, but any other 32-bit operation will zero-extend +// register. Truncate can be lowered to EXTRACT_SUBREG. CopyFromReg may +// be copying from a truncate. And x86's cmov doesn't do anything if the +// condition is false. But any other 32-bit operation will zero-extend // up to 64 bits. def def32 : PatLeaf<(i32 GR32:$src), [{ return N->getOpcode() != ISD::TRUNCATE && N->getOpcode() != TargetInstrInfo::EXTRACT_SUBREG && - N->getOpcode() != ISD::CopyFromReg; + N->getOpcode() != ISD::CopyFromReg && + N->getOpcode() != X86ISD::CMOV; }]>; // In the case of a 32-bit def that is known to implicitly zero-extend, |