Author: dim
Date: Fri Feb 15 23:12:58 2013
New Revision: 246858
URL: http://svnweb.freebsd.org/changeset/base/246858
Log:
Pull in r175057 from upstream llvm trunk:
X86: Disable generation of rep;movsl when %esi is used as a base pointer.
This happens when there is both stack realignment and a dynamic alloca in
the
function. If we overwrite %esi (rep;movsl uses fixed registers) we'll lose
the
base pointer and the next register spill will write into oblivion.
Fixes PR15249 and unbreaks firefox on i386/freebsd. Mozilla uses dynamic
allocas
and freebsd a 4 byte stack alignment.
MFC after: 1 week
Modified:
head/contrib/llvm/lib/Target/X86/X86SelectionDAGInfo.cpp
Modified: head/contrib/llvm/lib/Target/X86/X86SelectionDAGInfo.cpp
==============================================================================
--- head/contrib/llvm/lib/Target/X86/X86SelectionDAGInfo.cpp Fri Feb 15
23:12:35 2013 (r246857)
+++ head/contrib/llvm/lib/Target/X86/X86SelectionDAGInfo.cpp Fri Feb 15
23:12:58 2013 (r246858)
@@ -202,6 +202,14 @@ X86SelectionDAGInfo::EmitTargetCodeForMe
SrcPtrInfo.getAddrSpace() >= 256)
return SDValue();
+ // ESI might be used as a base pointer, in that case we can't simply
overwrite
+ // the register. Fall back to generic code.
+ const X86RegisterInfo *TRI =
+ static_cast<const X86RegisterInfo *>(DAG.getTarget().getRegisterInfo());
+ if (TRI->hasBasePointer(DAG.getMachineFunction()) &&
+ TRI->getBaseRegister() == X86::ESI)
+ return SDValue();
+
MVT AVT;
if (Align & 1)
AVT = MVT::i8;
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