[SystemZ] Fix fall-out from r314428
The expensive-checks build bot found a problem with the r314428 commit:
if CC is live after a ATOMIC_CMP_SWAPW instruction, it needs to be
marked as live-in to the block after the loop the pseudo gets expanded
to. This actually fixes a code-gen bug as well, since if the CC isn't
live, the CR and JLH are merged to a CRJLH which doesn't actually set
the condition code any more.
llvm-svn: 314465
diff --git a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
index be7c5e4..d49d731 100644
--- a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
@@ -6027,6 +6027,12 @@
MBB->addSuccessor(LoopMBB);
MBB->addSuccessor(DoneMBB);
+ // If the CC def wasn't dead in the ATOMIC_CMP_SWAPW, mark CC as live-in
+ // to the block after the loop. At this point, CC may have been defined
+ // either by the CR in LoopMBB or by the CS in SetMBB.
+ if (!MI.registerDefIsDead(SystemZ::CC))
+ DoneMBB->addLiveIn(SystemZ::CC);
+
MI.eraseFromParent();
return DoneMBB;
}