Fix a bug in the 3-address conversion of LEA when one of the operands is an
undef virtual register. The problem is that ProcessImplicitDefs removes the
definition of the register and marks all uses as undef. If we lose the undef
marker then we get a register which has no def, is not marked as undef. The
live interval analysis does not collect information for these virtual
registers and we crash in later passes.
Together with Michael Kuperstein <michael.m.kuperstein@intel.com>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160260 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86InstrInfo.cpp b/lib/Target/X86/X86InstrInfo.cpp
index 9f5f66e..8ba3194 100644
--- a/lib/Target/X86/X86InstrInfo.cpp
+++ b/lib/Target/X86/X86InstrInfo.cpp
@@ -2016,6 +2016,13 @@
.addReg(Dest, RegState::Define |
getDeadRegState(isDead)),
Src, isKill, Src2, isKill2);
+
+ // Preserve undefness of the operands.
+ bool isUndef = MI->getOperand(1).isUndef();
+ bool isUndef2 = MI->getOperand(2).isUndef();
+ NewMI->getOperand(1).setIsUndef(isUndef);
+ NewMI->getOperand(3).setIsUndef(isUndef2);
+
if (LV && isKill2)
LV->replaceKillInstruction(Src2, MI, NewMI);
break;