diff --git a/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp b/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp index 72ad30c06722..3398b376abfd 100644 --- a/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp +++ b/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp @@ -45,6 +45,7 @@ #include "llvm/Analysis/ScalarEvolutionExpressions.h" #include "llvm/Analysis/LoopInfo.h" #include "llvm/Support/CFG.h" +#include "llvm/Support/GetElementPtrTypeIterator.h" #include "llvm/Transforms/Utils/Local.h" #include "llvm/Support/CommandLine.h" #include "llvm/ADT/Statistic.h" @@ -135,9 +136,9 @@ namespace { while (isa(It)) ++It; if (It != BasicBlock::iterator(CI)) { // Splice the cast immediately after the operand in question. - I->getParent()->getInstList().splice(It, - CI->getParent()->getInstList(), - CI); + BasicBlock::InstListType &InstList = + I->getParent()->getInstList(); + InstList.splice(It, InstList, CI); } return CI; } @@ -345,7 +346,7 @@ DeleteTriviallyDeadInstructions(std::set &Insts) { if (Instruction *U = dyn_cast(I->getOperand(i))) Insts.insert(U); SE->deleteInstructionFromRecords(I); - I->getParent()->getInstList().erase(I); + I->eraseFromParent(); Changed = true; } } @@ -387,6 +388,34 @@ void IndVarSimplify::EliminatePointerRecurrence(PHINode *PN, // Update the GEP to use the new recurrence we just inserted. GEPI->setOperand(1, NewAdd); + // If the incoming value is a constant expr GEP, try peeling out the array + // 0 index if possible to make things simpler. + if (ConstantExpr *CE = dyn_cast(GEPI->getOperand(0))) + if (CE->getOpcode() == Instruction::GetElementPtr) { + unsigned NumOps = CE->getNumOperands(); + assert(NumOps > 1 && "CE folding didn't work!"); + if (CE->getOperand(NumOps-1)->isNullValue()) { + // Check to make sure the last index really is an array index. + gep_type_iterator GTI = gep_type_begin(GEPI); + for (unsigned i = 1, e = GEPI->getNumOperands()-1; + i != e; ++i, ++GTI) + /*empty*/; + if (isa(*GTI)) { + // Pull the last index out of the constant expr GEP. + std::vector CEIdxs(CE->op_begin()+1, CE->op_end()-1); + Constant *NCE = ConstantExpr::getGetElementPtr(CE->getOperand(0), + CEIdxs); + GetElementPtrInst *NGEPI = + new GetElementPtrInst(NCE, Constant::getNullValue(Type::IntTy), + NewAdd, GEPI->getName(), GEPI); + GEPI->replaceAllUsesWith(NGEPI); + GEPI->eraseFromParent(); + GEPI = NGEPI; + } + } + } + + // Finally, if there are any other users of the PHI node, we must // insert a new GEP instruction that uses the pre-incremented version // of the induction amount.