diff options
| -rw-r--r-- | lib/Transforms/Scalar/JumpThreading.cpp | 31 | ||||
| -rw-r--r-- | test/Transforms/JumpThreading/basic.ll | 7 |
2 files changed, 15 insertions, 23 deletions
diff --git a/lib/Transforms/Scalar/JumpThreading.cpp b/lib/Transforms/Scalar/JumpThreading.cpp index edb0412bfe..9531311551 100644 --- a/lib/Transforms/Scalar/JumpThreading.cpp +++ b/lib/Transforms/Scalar/JumpThreading.cpp @@ -1341,20 +1341,7 @@ bool JumpThreading::ThreadEdge(BasicBlock *BB, // At this point, the IR is fully up to date and consistent. Do a quick scan // over the new instructions and zap any that are constants or dead. This // frequently happens because of phi translation. - BI = NewBB->begin(); - for (BasicBlock::iterator E = NewBB->end(); BI != E; ) { - Instruction *Inst = BI++; - - if (Value *V = SimplifyInstruction(Inst, TD)) { - WeakVH BIHandle(BI); - ReplaceAndSimplifyAllUses(Inst, V, TD); - if (BIHandle == 0) - BI = NewBB->begin(); - continue; - } - - RecursivelyDeleteTriviallyDeadInstructions(Inst); - } + SimplifyInstructionsInBlock(NewBB, TD); // Threaded an edge! ++NumThreads; @@ -1425,9 +1412,6 @@ bool JumpThreading::DuplicateCondBranchOnPHIIntoPred(BasicBlock *BB, // mapping and using it to remap operands in the cloned instructions. for (; BI != BB->end(); ++BI) { Instruction *New = BI->clone(); - New->setName(BI->getName()); - PredBB->getInstList().insert(OldPredBranch, New); - ValueMapping[BI] = New; // Remap operands to patch up intra-block references. for (unsigned i = 0, e = New->getNumOperands(); i != e; ++i) @@ -1436,6 +1420,19 @@ bool JumpThreading::DuplicateCondBranchOnPHIIntoPred(BasicBlock *BB, if (I != ValueMapping.end()) New->setOperand(i, I->second); } + + // If this instruction can be simplified after the operands are updated, + // just use the simplified value instead. This frequently happens due to + // phi translation. + if (Value *IV = SimplifyInstruction(New, TD)) { + delete New; + ValueMapping[BI] = IV; + } else { + // Otherwise, insert the new instruction into the block. + New->setName(BI->getName()); + PredBB->getInstList().insert(OldPredBranch, New); + ValueMapping[BI] = New; + } } // Check to see if the targets of the branch had PHI nodes. If so, we need to diff --git a/test/Transforms/JumpThreading/basic.ll b/test/Transforms/JumpThreading/basic.ll index 34b4243d5b..503d301892 100644 --- a/test/Transforms/JumpThreading/basic.ll +++ b/test/Transforms/JumpThreading/basic.ll @@ -407,12 +407,7 @@ T2: F2: ret i32 %v1 -;; FIXME: CONSTANT FOLD on clone and when phi gets eliminated. - -; CHECK: Entry.Merge_crit_edge: -; CHECK-NEXT: %M1 = icmp eq i32 192, 192 -; CHECK-NEXT: %N2 = xor i1 true, %M1 -; CHECK-NEXT: br i1 %N2, label %T2, label %F2 +; CHECK: br i1 %cond, label %F2, label %Merge ; CHECK: Merge: ; CHECK-NEXT: %M = icmp eq i32 %v1, 192 |