The PPC MFCR instruction implicitly uses all 8 of the CR
registers. Currently it is not so marked, which leads to
VCMPEQ instructions that feed into it getting deleted.
If it is so marked, local RA complains about this sequence:
vreg = MCRF CR0
MFCR <kill of whatever preg got assigned to vreg>
All current uses of this instruction are only interested in
one of the 8 CR registers, so redefine MFCR to be a normal
unary instruction with a CR input (which is emitted only as
a comment). That avoids all problems. 7739628.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104238 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCInstrInfo.cpp b/lib/Target/PowerPC/PPCInstrInfo.cpp
index ae95ae4..1b7a778 100644
--- a/lib/Target/PowerPC/PPCInstrInfo.cpp
+++ b/lib/Target/PowerPC/PPCInstrInfo.cpp
@@ -442,7 +442,8 @@
// issue a MFCR to save all of the CRBits.
unsigned ScratchReg = TM.getSubtargetImpl()->isDarwinABI() ?
PPC::R2 : PPC::R0;
- NewMIs.push_back(BuildMI(MF, DL, get(PPC::MFCR), ScratchReg));
+ NewMIs.push_back(BuildMI(MF, DL, get(PPC::MFCRpseud), ScratchReg)
+ .addReg(SrcReg, getKillRegState(isKill)));
// If the saved register wasn't CR0, shift the bits left so that they are
// in CR0's slot.