[PowerPC] fix up in redundant compare elimination
This patch fixes a potential problem in my previous commit (https://reviews.llvm.org/rL312514) by introducing an additional check.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@318266 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCMIPeephole.cpp b/lib/Target/PowerPC/PPCMIPeephole.cpp
index 80b7ac2..0a84fe3 100644
--- a/lib/Target/PowerPC/PPCMIPeephole.cpp
+++ b/lib/Target/PowerPC/PPCMIPeephole.cpp
@@ -814,8 +814,12 @@
!MRI->hasOneNonDBGUse(CndReg))
return false;
- // We skip this BB if a physical register is used in comparison.
MachineInstr *CMPI = MRI->getVRegDef(CndReg);
+ // We assume compare and branch are in the same BB for ease of analysis.
+ if (CMPI->getParent() != &BB)
+ return false;
+
+ // We skip this BB if a physical register is used in comparison.
for (MachineOperand &MO : CMPI->operands())
if (MO.isReg() && !TargetRegisterInfo::isVirtualRegister(MO.getReg()))
return false;
@@ -921,7 +925,7 @@
//
// As partially redundant case, we additionally handle if MBB2 has one
// additional predecessor, which has only one successor (MBB2).
- // In this case, we move the compre instruction originally in MBB2 into
+ // In this case, we move the compare instruction originally in MBB2 into
// MBBtoMoveCmp. This partially redundant case is typically appear by
// compiling a while loop; here, MBBtoMoveCmp is the loop preheader.
//
