[SimplifyCFG] Move a portion of an if statement that should already be implied to...

Summary: In this code we got to Dom by following the predecessor link of BB. So it stands to reason that BB should also show up as a successor of Dom's terminator right? There isn't a way to have the CFG connect in only one direction is there?

Reviewers: jmolloy, davide, mcrosier

Reviewed By: mcrosier

Subscribers: mcrosier, llvm-commits

Differential Revision: https://reviews.llvm.org/D35025

llvm-svn: 307276

diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index e724b0a28c3224e2618b122ee757d9cfcffc5c0d..dee658f98393208855d0bd6dbab20b070b23951f 100644 (file)
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -5754,8 +5754,8 @@ bool SimplifyCFGOpt::SimplifyCondBranch(BranchInst *BI, IRBuilder<> &Builder) {
   if (BasicBlock *Dom = BB->getSinglePredecessor()) {
     auto *PBI = dyn_cast_or_null<BranchInst>(Dom->getTerminator());
     if (PBI && PBI->isConditional() &&
-        PBI->getSuccessor(0) != PBI->getSuccessor(1) &&
-        (PBI->getSuccessor(0) == BB || PBI->getSuccessor(1) == BB)) {
+        PBI->getSuccessor(0) != PBI->getSuccessor(1)) {
+      assert(PBI->getSuccessor(0) == BB || PBI->getSuccessor(1) == BB);
       bool CondIsFalse = PBI->getSuccessor(1) == BB;
       Optional<bool> Implication = isImpliedCondition(
           PBI->getCondition(), BI->getCondition(), DL, CondIsFalse);