Perform an intelligent splice of the predecessor with the single successor.
If the predecessor's being spliced into a landing pad, then we need the PHIs to
come first and the rest of the predecessor's code to come *after* the landing
pad instruction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193035 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Utils/Local.cpp b/lib/Transforms/Utils/Local.cpp
index 82b8da3..78217c8 100644
--- a/lib/Transforms/Utils/Local.cpp
+++ b/lib/Transforms/Utils/Local.cpp
@@ -503,7 +503,19 @@
// Splice all the instructions from PredBB to DestBB.
PredBB->getTerminator()->eraseFromParent();
- DestBB->getInstList().splice(DestBB->begin(), PredBB->getInstList());
+
+ // First splice over the PHI nodes.
+ BasicBlock::iterator PI = PredBB->begin();
+ while (isa<PHINode>(PI))
+ ++PI;
+
+ if (PI != PredBB->begin())
+ DestBB->getInstList().splice(DestBB->begin(), PredBB->getInstList(),
+ PredBB->begin(), PI);
+
+ // Now splice over the rest of the instructions.
+ DestBB->getInstList().splice(DestBB->getFirstInsertionPt(),
+ PredBB->getInstList(), PI, PredBB->end());
if (P) {
DominatorTree *DT = P->getAnalysisIfAvailable<DominatorTree>();
@@ -513,6 +525,7 @@
DT->eraseNode(PredBB);
}
}
+
// Nuke BB.
PredBB->eraseFromParent();
}