It's not safe eliminate copies where src and dst have different sub-register indices.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103450 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/VirtRegRewriter.cpp b/lib/CodeGen/VirtRegRewriter.cpp
index 9b46273..9c32480 100644
--- a/lib/CodeGen/VirtRegRewriter.cpp
+++ b/lib/CodeGen/VirtRegRewriter.cpp
@@ -2425,7 +2425,8 @@
// eliminate this or else the undef marker is lost and it will
// confuses the scavenger. This is extremely rare.
unsigned Src, Dst, SrcSR, DstSR;
- if (TII->isMoveInstr(MI, Src, Dst, SrcSR, DstSR) && Src == Dst &&
+ if (TII->isMoveInstr(MI, Src, Dst, SrcSR, DstSR) &&
+ Src == Dst && SrcSR == DstSR &&
!MI.findRegisterUseOperand(Src)->isUndef()) {
++NumDCE;
DEBUG(dbgs() << "Removing now-noop copy: " << MI);
@@ -2514,7 +2515,8 @@
// instruction before considering the dest reg to be changed.
{
unsigned Src, Dst, SrcSR, DstSR;
- if (TII->isMoveInstr(MI, Src, Dst, SrcSR, DstSR) && Src == Dst) {
+ if (TII->isMoveInstr(MI, Src, Dst, SrcSR, DstSR) &&
+ Src == Dst && SrcSR == DstSR) {
++NumDCE;
DEBUG(dbgs() << "Removing now-noop copy: " << MI);
InvalidateKills(MI, TRI, RegKills, KillOps);