[AMDGPU] Do not annotate an else branch if there is a kill

As llvm.amdgcn.kill is lowered to a terminator it can cause
else branch annotations to end up in the wrong block.
Do not annotate conditionals as else branches where there is
a kill to avoid this.

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D97427

1 files changed, 12 insertions, 1 deletions

diff --git a/llvm/lib/Target/AMDGPU/SIAnnotateControlFlow.cpp b/llvm/lib/Target/AMDGPU/SIAnnotateControlFlow.cpp
index 625749deb3a8..3447ea33e92e 100644
--- a/llvm/lib/Target/AMDGPU/SIAnnotateControlFlow.cpp
+++ b/llvm/lib/Target/AMDGPU/SIAnnotateControlFlow.cpp
@@ -71,6 +71,8 @@ class SIAnnotateControlFlow : public FunctionPass {
 
   bool isElse(PHINode *Phi);
 
+  bool hasKill(const BasicBlock *BB);
+
   void eraseIfUnused(PHINode *Phi);
 
   void openIf(BranchInst *Term);
@@ -181,6 +183,15 @@ bool SIAnnotateControlFlow::isElse(PHINode *Phi) {
   return true;
 }
 
+bool SIAnnotateControlFlow::hasKill(const BasicBlock *BB) {
+  for (const Instruction &I : *BB) {
+    if (const CallInst *CI = dyn_cast<CallInst>(&I))
+      if (CI->getIntrinsicID() == Intrinsic::amdgcn_kill)
+        return true;
+  }
+  return false;
+}
+
 // Erase "Phi" if it is not used any more
 void SIAnnotateControlFlow::eraseIfUnused(PHINode *Phi) {
   if (RecursivelyDeleteDeadPHINode(Phi)) {
@@ -339,7 +350,7 @@ bool SIAnnotateControlFlow::runOnFunction(Function &F) {
 
     if (isTopOfStack(BB)) {
       PHINode *Phi = dyn_cast<PHINode>(Term->getCondition());
-      if (Phi && Phi->getParent() == BB && isElse(Phi)) {
+      if (Phi && Phi->getParent() == BB && isElse(Phi) && !hasKill(BB)) {
         insertElse(Term);
         eraseIfUnused(Phi);
         continue;