diff options
| -rw-r--r-- | lib/Transforms/Scalar/IndVarSimplify.cpp | 27 | ||||
| -rw-r--r-- | test/Transforms/IndVarSimplify/exitcnt-const-arstart-const-opt.ll | 25 |
2 files changed, 48 insertions, 4 deletions
diff --git a/lib/Transforms/Scalar/IndVarSimplify.cpp b/lib/Transforms/Scalar/IndVarSimplify.cpp index df11e92..ddb5b27 100644 --- a/lib/Transforms/Scalar/IndVarSimplify.cpp +++ b/lib/Transforms/Scalar/IndVarSimplify.cpp @@ -1612,10 +1612,29 @@ LinearFunctionTestReplace(Loop *L, << " IVCount:\t" << *IVCount << "\n"); IRBuilder<> Builder(BI); - if (SE->getTypeSizeInBits(CmpIndVar->getType()) - > SE->getTypeSizeInBits(ExitCnt->getType())) { - CmpIndVar = Builder.CreateTrunc(CmpIndVar, ExitCnt->getType(), - "lftr.wideiv"); + + unsigned CmpIndVarSize = SE->getTypeSizeInBits(CmpIndVar->getType()); + unsigned ExitCntSize = SE->getTypeSizeInBits(ExitCnt->getType()); + if (CmpIndVarSize > ExitCntSize) { + const SCEVAddRecExpr *AR = cast<SCEVAddRecExpr>(SE->getSCEV(IndVar)); + const SCEV *ARStart = AR->getStart(); + const SCEV *ARStep = AR->getStepRecurrence(*SE); + if (isa<SCEVConstant>(ARStart) && isa<SCEVConstant>(IVCount)) { + const APInt &Start = cast<SCEVConstant>(ARStart)->getValue()->getValue(); + const APInt &Count = cast<SCEVConstant>(IVCount)->getValue()->getValue(); + + APInt NewLimit; + if (cast<SCEVConstant>(ARStep)->getValue()->isNegative()) + NewLimit = Start - Count.zext(CmpIndVarSize); + else + NewLimit = Start + Count.zext(CmpIndVarSize); + ExitCnt = ConstantInt::get(CmpIndVar->getType(), NewLimit); + + DEBUG(dbgs() << " Widen RHS:\t" << *ExitCnt << "\n"); + } else { + CmpIndVar = Builder.CreateTrunc(CmpIndVar, ExitCnt->getType(), + "lftr.wideiv"); + } } Value *Cond = Builder.CreateICmp(P, CmpIndVar, ExitCnt, "exitcond"); diff --git a/test/Transforms/IndVarSimplify/exitcnt-const-arstart-const-opt.ll b/test/Transforms/IndVarSimplify/exitcnt-const-arstart-const-opt.ll new file mode 100644 index 0000000..185a67f --- /dev/null +++ b/test/Transforms/IndVarSimplify/exitcnt-const-arstart-const-opt.ll @@ -0,0 +1,25 @@ +;RUN: opt -S %s -indvars | FileCheck %s + +; Function Attrs: nounwind uwtable +define void @foo() #0 { +entry: + br label %for.body + +for.body: ; preds = %entry, %for.body + %i.01 = phi i16 [ 0, %entry ], [ %inc, %for.body ] + %conv2 = sext i16 %i.01 to i32 + call void @bar(i32 %conv2) #1 + %inc = add i16 %i.01, 1 +;CHECK-NOT: %lftr.wideiv = trunc i32 %indvars.iv.next to i16 +;CHECK: %exitcond = icmp ne i32 %indvars.iv.next, 512 + %cmp = icmp slt i16 %inc, 512 + br i1 %cmp, label %for.body, label %for.end + +for.end: ; preds = %for.body + ret void +} + +declare void @bar(i32) + +attributes #0 = { nounwind uwtable } +attributes #1 = { nounwind } |