Ignore dbg intrinsics while folding switch instruction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63802 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp
index ba00f61..d9c4b69 100644
--- a/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -1330,6 +1330,20 @@
return true;
}
+/// isTerminatorFirstRelevantInsn - Return true if Term is very first
+/// instruction ignoring Phi nodes and dbg intrinsics.
+static bool isTerminatorFirstRelevantInsn(BasicBlock *BB, Instruction *Term) {
+ BasicBlock::iterator BBI = Term;
+ while (BBI != BB->begin()) {
+ --BBI;
+ if (!isa<DbgInfoIntrinsic>(BBI))
+ break;
+ }
+ if (isa<PHINode>(BBI) || &*BBI == Term)
+ return true;
+ return false;
+}
+
/// SimplifyCondBranchToTwoReturns - If we found a conditional branch that goes
/// to two returning blocks, try to merge them together into one return,
/// introducing a select if the return values disagree.
@@ -1343,12 +1357,10 @@
// Check to ensure both blocks are empty (just a return) or optionally empty
// with PHI nodes. If there are other instructions, merging would cause extra
// computation on one path or the other.
- BasicBlock::iterator BBI = TrueRet;
- if (BBI != TrueSucc->begin() && !isa<PHINode>(--BBI))
- return false; // Not empty with optional phi nodes.
- BBI = FalseRet;
- if (BBI != FalseSucc->begin() && !isa<PHINode>(--BBI))
- return false; // Not empty with optional phi nodes.
+ if (!isTerminatorFirstRelevantInsn(TrueSucc, TrueRet))
+ return false;
+ if (!isTerminatorFirstRelevantInsn(FalseSucc, FalseRet))
+ return false;
// Okay, we found a branch that is going to two return nodes. If
// there is no return value for this function, just change the
@@ -1750,8 +1762,7 @@
// different return values, fold the replace the branch/return with a select
// and return.
if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) {
- BasicBlock::iterator BBI = BB->getTerminator();
- if (BBI == BB->begin() || isa<PHINode>(--BBI)) {
+ if (isTerminatorFirstRelevantInsn(BB, BB->getTerminator())) {
// Find predecessors that end with branches.
SmallVector<BasicBlock*, 8> UncondBranchPreds;
SmallVector<BranchInst*, 8> CondBranchPreds;