From 88e06db1160672d7152a2bd9db7fcf7977f6bbbd Mon Sep 17 00:00:00 2001 From: Dan Gohman Date: Fri, 22 May 2009 07:14:20 +0000 Subject: Fix a thinko in the code that adapted SCEVMulExpr operands for use in expanding SCEVAddExprs with GEPs. The operands of a SCEVMulExpr need to be multiplied together, not added. llvm-svn: 72250 --- llvm/lib/Analysis/ScalarEvolutionExpander.cpp | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) (limited to 'llvm/lib/Analysis/ScalarEvolutionExpander.cpp') diff --git a/llvm/lib/Analysis/ScalarEvolutionExpander.cpp b/llvm/lib/Analysis/ScalarEvolutionExpander.cpp index d110385fb3e..507ced74fd1 100644 --- a/llvm/lib/Analysis/ScalarEvolutionExpander.cpp +++ b/llvm/lib/Analysis/ScalarEvolutionExpander.cpp @@ -168,6 +168,8 @@ Value *SCEVExpander::expandAddToGEP(const SCEVAddExpr *S, std::vector ScaledOps; for (unsigned i = 0, e = Ops.size(); i != e; ++i) { if (ElSize != 0) { + // For a Constant, check for a multiple of the pointer type's + // scale size. if (const SCEVConstant *C = dyn_cast(Ops[i])) if (!C->getValue()->getValue().srem(ElSize)) { ConstantInt *CI = @@ -176,13 +178,19 @@ Value *SCEVExpander::expandAddToGEP(const SCEVAddExpr *S, ScaledOps.push_back(Div); continue; } + // In a Mul, check if there is a constant operand which is a multiple + // of the pointer type's scale size. if (const SCEVMulExpr *M = dyn_cast(Ops[i])) if (const SCEVConstant *C = dyn_cast(M->getOperand(0))) - if (C->getValue()->getValue() == ElSize) { - for (unsigned j = 1, f = M->getNumOperands(); j != f; ++j) - ScaledOps.push_back(M->getOperand(j)); + if (!C->getValue()->getValue().srem(ElSize)) { + std::vector NewMulOps(M->getOperands()); + NewMulOps[0] = + SE.getConstant(C->getValue()->getValue().sdiv(ElSize)); + ScaledOps.push_back(SE.getMulExpr(NewMulOps)); continue; } + // In an Unknown, check if the underlying value is a Mul by a constant + // which is equal to the pointer type's scale size. if (const SCEVUnknown *U = dyn_cast(Ops[i])) if (BinaryOperator *BO = dyn_cast(U->getValue())) if (BO->getOpcode() == Instruction::Mul) @@ -191,6 +199,8 @@ Value *SCEVExpander::expandAddToGEP(const SCEVAddExpr *S, ScaledOps.push_back(SE.getUnknown(BO->getOperand(0))); continue; } + // If the pointer type's scale size is 1, no scaling is necessary + // and any value can be used. if (ElSize == 1) { ScaledOps.push_back(Ops[i]); continue; -- cgit v1.2.3