Propagate subreg index when promoting a load to a copy.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56085 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/VirtRegMap.cpp b/lib/CodeGen/VirtRegMap.cpp
index e783e04..3e27fe2 100644
--- a/lib/CodeGen/VirtRegMap.cpp
+++ b/lib/CodeGen/VirtRegMap.cpp
@@ -1588,11 +1588,18 @@
if (DestReg != InReg) {
const TargetRegisterClass *RC = RegInfo->getRegClass(VirtReg);
TII->copyRegToReg(MBB, &MI, DestReg, InReg, RC, RC);
+ MachineOperand *DefMO = MI.findRegisterDefOperand(DestReg);
+ unsigned SubIdx = DefMO->getSubReg();
// Revisit the copy so we make sure to notice the effects of the
// operation on the destreg (either needing to RA it if it's
// virtual or needing to clobber any values if it's physical).
NextMII = &MI;
--NextMII; // backtrack to the copy.
+ // Propagate the sub-register index over.
+ if (SubIdx) {
+ DefMO = NextMII->findRegisterDefOperand(DestReg);
+ DefMO->setSubReg(SubIdx);
+ }
BackTracked = true;
} else {
DOUT << "Removing now-noop copy: " << MI;