Changes in directory llvm/lib/Transforms/Scalar:
InstructionCombining.cpp updated: 1.539 -> 1.540 --- Log message: reenable factoring of GEP expressions, being more precise about the case that it bad to do. --- Diffs of the changes: (+10 -5) InstructionCombining.cpp | 15 ++++++++++----- 1 files changed, 10 insertions(+), 5 deletions(-) Index: llvm/lib/Transforms/Scalar/InstructionCombining.cpp diff -u llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.539 llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.540 --- llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.539 Wed Nov 8 13:29:23 2006 +++ llvm/lib/Transforms/Scalar/InstructionCombining.cpp Wed Nov 8 13:42:28 2006 @@ -6788,12 +6788,17 @@ if (I->getOperand(1) != RHSVal) RHSVal = 0; } - // Otherwise, this is safe and profitable to transform. Create up to two phi - // nodes. - PHINode *NewLHS = 0, *NewRHS = 0; + // Otherwise, this is safe to transform, determine if it is profitable. + + // If this is a GEP, and if the index (not the pointer) needs a PHI, bail out. + // Indexes are often folded into load/store instructions, so we don't want to + // hide them behind a phi. + if (isa<GetElementPtrInst>(FirstInst) && RHSVal == 0) + return 0; + Value *InLHS = FirstInst->getOperand(0); Value *InRHS = FirstInst->getOperand(1); - + PHINode *NewLHS = 0, *NewRHS = 0; if (LHSVal == 0) { NewLHS = new PHINode(LHSType, FirstInst->getOperand(0)->getName()+".pn"); NewLHS->reserveOperandSpace(PN.getNumOperands()/2); @@ -6875,7 +6880,7 @@ !isSafeToSinkLoad(LI)) return 0; } else if (isa<GetElementPtrInst>(FirstInst)) { - if (0 && FirstInst->getNumOperands() == 2) + if (FirstInst->getNumOperands() == 2) return FoldPHIArgBinOpIntoPHI(PN); // Can't handle general GEPs yet. return 0; _______________________________________________ llvm-commits mailing list llvm-commits@cs.uiuc.edu http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits