When deleting a phi cycle after looking through copies, constrain the register
to match its final use.
With this change, all of test-suite compiles for Thumb2 with -verify-coalescing
enabled.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142287 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/OptimizePHIs.cpp b/lib/CodeGen/OptimizePHIs.cpp
index c05be13..85fa041 100644
--- a/lib/CodeGen/OptimizePHIs.cpp
+++ b/lib/CodeGen/OptimizePHIs.cpp
@@ -165,7 +165,11 @@
InstrSet PHIsInCycle;
if (IsSingleValuePHICycle(MI, SingleValReg, PHIsInCycle) &&
SingleValReg != 0) {
- MRI->replaceRegWith(MI->getOperand(0).getReg(), SingleValReg);
+ unsigned OldReg = MI->getOperand(0).getReg();
+ if (!MRI->constrainRegClass(SingleValReg, MRI->getRegClass(OldReg)))
+ continue;
+
+ MRI->replaceRegWith(OldReg, SingleValReg);
MI->eraseFromParent();
++NumPHICycles;
Changed = true;