diff options
Diffstat (limited to 'lib/Transforms')
| -rw-r--r-- | lib/Transforms/Scalar/JumpThreading.cpp | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/lib/Transforms/Scalar/JumpThreading.cpp b/lib/Transforms/Scalar/JumpThreading.cpp index 92e40e66d4..be94025404 100644 --- a/lib/Transforms/Scalar/JumpThreading.cpp +++ b/lib/Transforms/Scalar/JumpThreading.cpp @@ -250,6 +250,13 @@ bool JumpThreading::ProcessJumpOnPHI(PHINode *PN) { SuccBB = SI->getSuccessor(SI->findCaseValue(PredCst)); } + // If threading to the same block as we come from, we would infinite loop. + if (SuccBB == BB) { + DOUT << " Not threading BB '" << BB->getNameStart() + << "' - would thread to self!\n"; + return false; + } + // And finally, do it! DOUT << " Threading edge from '" << PredBB->getNameStart() << "' to '" << SuccBB->getNameStart() << "' with cost: " << JumpThreadCost @@ -319,6 +326,13 @@ bool JumpThreading::ProcessBranchOnLogical(Value *V, BasicBlock *BB, // 'true' block. BasicBlock *SuccBB = BB->getTerminator()->getSuccessor(isAnd); + // If threading to the same block as we come from, we would infinite loop. + if (SuccBB == BB) { + DOUT << " Not threading BB '" << BB->getNameStart() + << "' - would thread to self!\n"; + return false; + } + // And finally, do it! DOUT << " Threading edge through bool from '" << PredBB->getNameStart() << "' to '" << SuccBB->getNameStart() << "' with cost: " @@ -390,6 +404,14 @@ bool JumpThreading::ProcessBranchOnCompare(CmpInst *Cmp, BasicBlock *BB) { // Next, get our successor. BasicBlock *SuccBB = BB->getTerminator()->getSuccessor(!TrueDirection); + // If threading to the same block as we come from, we would infinite loop. + if (SuccBB == BB) { + DOUT << " Not threading BB '" << BB->getNameStart() + << "' - would thread to self!\n"; + return false; + } + + // And finally, do it! DOUT << " Threading edge through bool from '" << PredBB->getNameStart() << "' to '" << SuccBB->getNameStart() << "' with cost: " |