[X86] Fix killed flag handling in X86FixupLea pass

When pass creates a MOV instruction for 
lea (%base,%index,1), %dst => mov %base,%dst; add %index,%dst
modification it should clean the killed flag for base
if base is equal to index.

Otherwise verifier complains about usage of killed register in add instruction.

Reviewers: lsaba, zvi, zansari, aaboud
Reviewed By: lsaba
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D42522

llvm-svn: 323497
diff --git a/llvm/lib/Target/X86/X86FixupLEAs.cpp b/llvm/lib/Target/X86/X86FixupLEAs.cpp
index b41bf99..64678c0 100644
--- a/llvm/lib/Target/X86/X86FixupLEAs.cpp
+++ b/llvm/lib/Target/X86/X86FixupLEAs.cpp
@@ -548,7 +548,8 @@
 
   // lea (%base,%index,1), %dst => mov %base,%dst; add %index,%dst
   if (IsScale1 && !hasLEAOffset(Offset)) {
-    TII->copyPhysReg(*MFI, MI, DL, DstR, BaseR, Base.isKill());
+    bool BIK = Base.isKill() && BaseR != IndexR;
+    TII->copyPhysReg(*MFI, MI, DL, DstR, BaseR, BIK);
     DEBUG(MI.getPrevNode()->dump(););
 
     MachineInstr *NewMI =