Index: llvm/trunk/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp =================================================================== --- llvm/trunk/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp +++ llvm/trunk/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp @@ -37,6 +37,7 @@ STATISTIC(NumReturns, "Number of return values propagated"); STATISTIC(NumDeadCases, "Number of switch cases removed"); STATISTIC(NumSDivs, "Number of sdiv converted to udiv"); +STATISTIC(NumSRems, "Number of srem converted to urem"); namespace { class CorrelatedValuePropagation : public FunctionPass { @@ -325,31 +326,50 @@ return true; } -/// See if LazyValueInfo's ability to exploit edge conditions or range -/// information is sufficient to prove the both operands of this SDiv are -/// positive. If this is the case, replace the SDiv with a UDiv. Even for local -/// conditions, this can sometimes prove conditions instcombine can't by -/// exploiting range information. -static bool processSDiv(BinaryOperator *SDI, LazyValueInfo *LVI) { - if (SDI->getType()->isVectorTy()) - return false; - +// Helper function to rewrite srem and sdiv. As a policy choice, we choose not +// to waste compile time on anything where the operands are local defs. While +// LVI can sometimes reason about such cases, it's not its primary purpose. +static bool hasLocalDefs(BinaryOperator *SDI) { for (Value *O : SDI->operands()) { - // As a policy choice, we choose not to waste compile time on anything where - // the operands are local defs. While LVI can sometimes reason about such - // cases, it's not its primary purpose. auto *I = dyn_cast(O); if (I && I->getParent() == SDI->getParent()) - return false; + return true; } + return false; +} +static bool hasPositiveOperands(BinaryOperator *SDI, LazyValueInfo *LVI) { Constant *Zero = ConstantInt::get(SDI->getType(), 0); for (Value *O : SDI->operands()) { - LazyValueInfo::Tristate Result = - LVI->getPredicateAt(ICmpInst::ICMP_SGE, O, Zero, SDI); + auto Result = LVI->getPredicateAt(ICmpInst::ICMP_SGE, O, Zero, SDI); if (Result != LazyValueInfo::True) return false; } + return true; +} + +static bool processSRem(BinaryOperator *SDI, LazyValueInfo *LVI) { + if (SDI->getType()->isVectorTy() || hasLocalDefs(SDI) || + !hasPositiveOperands(SDI, LVI)) + return false; + + ++NumSRems; + auto *BO = BinaryOperator::CreateURem(SDI->getOperand(0), SDI->getOperand(1), + SDI->getName(), SDI); + SDI->replaceAllUsesWith(BO); + SDI->eraseFromParent(); + return true; +} + +/// See if LazyValueInfo's ability to exploit edge conditions or range +/// information is sufficient to prove the both operands of this SDiv are +/// positive. If this is the case, replace the SDiv with a UDiv. Even for local +/// conditions, this can sometimes prove conditions instcombine can't by +/// exploiting range information. +static bool processSDiv(BinaryOperator *SDI, LazyValueInfo *LVI) { + if (SDI->getType()->isVectorTy() || hasLocalDefs(SDI) || + !hasPositiveOperands(SDI, LVI)) + return false; ++NumSDivs; auto *BO = BinaryOperator::CreateUDiv(SDI->getOperand(0), SDI->getOperand(1), @@ -410,6 +430,9 @@ case Instruction::Invoke: BBChanged |= processCallSite(CallSite(II), LVI); break; + case Instruction::SRem: + BBChanged |= processSRem(cast(II), LVI); + break; case Instruction::SDiv: BBChanged |= processSDiv(cast(II), LVI); break; Index: llvm/trunk/test/Transforms/CorrelatedValuePropagation/srem.ll =================================================================== --- llvm/trunk/test/Transforms/CorrelatedValuePropagation/srem.ll +++ llvm/trunk/test/Transforms/CorrelatedValuePropagation/srem.ll @@ -0,0 +1,21 @@ +; RUN: opt < %s -correlated-propagation -S | FileCheck %s + +target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64" +target triple = "thumbv7m-arm-none-eabi" + +define void @h(i32* nocapture %p, i32 %x) local_unnamed_addr #0 { +entry: +; CHECK-LABEL: @h( +; CHECK: urem + + %cmp = icmp sgt i32 %x, 0 + br i1 %cmp, label %if.then, label %if.end + +if.then: + %rem2 = srem i32 %x, 10 + store i32 %rem2, i32* %p, align 4 + br label %if.end + +if.end: + ret void +}