Do not replace operands of pseudo instructions with register $zero.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156663 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGen/Mips/atomic.ll b/test/CodeGen/Mips/atomic.ll
index a4763b1..e181610 100644
--- a/test/CodeGen/Mips/atomic.ll
+++ b/test/CodeGen/Mips/atomic.ll
@@ -242,3 +242,19 @@
; CHECK: sync 0
}
+; make sure that this assertion in
+; TwoAddressInstructionPass::TryInstructionTransform does not fail:
+;
+; line 1203: assert(TargetRegisterInfo::isVirtualRegister(regB) &&
+;
+; it failed when MipsDAGToDAGISel::ReplaceUsesWithZeroReg replaced an
+; operand of an atomic instruction with register $zero.
+@a = external global i32
+
+define i32 @zeroreg() nounwind {
+entry:
+ %0 = cmpxchg i32* @a, i32 1, i32 0 seq_cst
+ %1 = icmp eq i32 %0, 1
+ %conv = zext i1 %1 to i32
+ ret i32 %conv
+}