diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Transforms/Utils/SimplifyCFG.cpp | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp index 69c08e55283..e44a04aaba6 100644 --- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp @@ -2390,6 +2390,19 @@ static bool SimplifyCondBranchToCondBranch(BranchInst *PBI, BranchInst *BI, if (CE->canTrap()) return false; + // If BI is reached from the true path of PBI and PBI's condition implies + // BI's condition, we know the direction of the BI branch. + if (PBI->getSuccessor(0) == BI->getParent() && + isImpliedCondition(PBI->getCondition(), BI->getCondition()) && + PBI->getSuccessor(0) != PBI->getSuccessor(1) && + BB->getSinglePredecessor()) { + // Turn this into a branch on constant. + auto *OldCond = BI->getCondition(); + BI->setCondition(ConstantInt::getTrue(BB->getContext())); + RecursivelyDeleteTriviallyDeadInstructions(OldCond); + return true; // Nuke the branch on constant. + } + // If this is a conditional branch in an empty block, and if any // predecessors are a conditional branch to one of our destinations, // fold the conditions into logical ops and one cond br. |
