diff options
Diffstat (limited to 'lib/Transforms/Utils/LCSSA.cpp')
| -rw-r--r-- | lib/Transforms/Utils/LCSSA.cpp | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/lib/Transforms/Utils/LCSSA.cpp b/lib/Transforms/Utils/LCSSA.cpp index a8813eb1ff..b4afedab7b 100644 --- a/lib/Transforms/Utils/LCSSA.cpp +++ b/lib/Transforms/Utils/LCSSA.cpp @@ -63,6 +63,9 @@ namespace { /// virtual void getAnalysisUsage(AnalysisUsage &AU) const { AU.setPreservesCFG(); + + // LCSSA doesn't actually require LoopSimplify, but the PassManager + // doesn't know how to schedule LoopSimplify by itself. AU.addRequiredID(LoopSimplifyID); AU.addPreservedID(LoopSimplifyID); AU.addRequiredTransitive<LoopInfo>(); @@ -214,7 +217,7 @@ bool LCSSA::ProcessInstruction(Instruction *Inst, SSAUpdate.Initialize(Inst); // Insert the LCSSA phi's into all of the exit blocks dominated by the - // value., and add them to the Phi's map. + // value, and add them to the Phi's map. for (SmallVectorImpl<BasicBlock*>::const_iterator BBI = ExitBlocks.begin(), BBE = ExitBlocks.end(); BBI != BBE; ++BBI) { BasicBlock *ExitBB = *BBI; @@ -228,8 +231,17 @@ bool LCSSA::ProcessInstruction(Instruction *Inst, PN->reserveOperandSpace(PredCache.GetNumPreds(ExitBB)); // Add inputs from inside the loop for this PHI. - for (BasicBlock **PI = PredCache.GetPreds(ExitBB); *PI; ++PI) + for (BasicBlock **PI = PredCache.GetPreds(ExitBB); *PI; ++PI) { PN->addIncoming(Inst, *PI); + + // If the exit block has a predecessor not within the loop, arrange for + // the incomging value use corresponding to that predecessor to be + // rewritten in terms of a different LCSSA PHI. + if (!inLoop(*PI)) + UsesToRewrite.push_back( + &PN->getOperandUse( + PN->getOperandNumForIncomingValue(PN->getNumIncomingValues()-1))); + } // Remember that this phi makes the value alive in this block. SSAUpdate.AddAvailableValue(ExitBB, PN); |