Update phis in AMDGPUUnifyDivergentExitNodes
Original patch https://reviews.llvm.org/D63659 from
Steven Perron <stevenperron@google.com>
The pass AMDGPUUnifyDivergentExitNodes does not update the phi nodes in
the successors of blocks that is splits. This is fixed by calling
BasicBlock::splitBasicBlock to split the block instead of doing it
manually. This does extra work because a new conditional branch is
created in BB which is immediately replaced, but I think the simplicity
is worth it. It also helps make the code more future proof in case other
things need to be updated.
llvm-svn: 364342
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUUnifyDivergentExitNodes.cpp b/llvm/lib/Target/AMDGPU/AMDGPUUnifyDivergentExitNodes.cpp
index 6550dc3..396e0ed 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUUnifyDivergentExitNodes.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUUnifyDivergentExitNodes.cpp
@@ -198,14 +198,11 @@
BranchInst::Create(LoopHeaderBB, DummyReturnBB, BoolTrue, BB);
} else { // Conditional branch.
// Create a new transition block to hold the conditional branch.
- BasicBlock *TransitionBB = BasicBlock::Create(F.getContext(),
- "TransitionBlock", &F);
+ BasicBlock *TransitionBB = BB->splitBasicBlock(BI, "TransitionBlock");
- // Move BI from BB to the new transition block.
- BI->removeFromParent();
- TransitionBB->getInstList().push_back(BI);
-
- // Create a branch that will always branch to the transition block.
+ // Create a branch that will always branch to the transition block and
+ // references DummyReturnBB.
+ BB->getTerminator()->eraseFromParent();
BranchInst::Create(TransitionBB, DummyReturnBB, BoolTrue, BB);
}
}