Index: lib/Analysis/ScalarEvolutionExpander.cpp =================================================================== --- lib/Analysis/ScalarEvolutionExpander.cpp +++ lib/Analysis/ScalarEvolutionExpander.cpp @@ -878,7 +878,7 @@ if (IncV->mayHaveSideEffects()) return false; - if (IncV != PN) + if (IncV == PN) return true; return isNormalAddRecExprPHI(PN, IncV, L); Index: test/Transforms/IndVarSimplify/scevexpander-phi-base-case.ll =================================================================== --- /dev/null +++ test/Transforms/IndVarSimplify/scevexpander-phi-base-case.ll @@ -0,0 +1,63 @@ +; RUN: opt -indvars -S < %s | FileCheck %s + +define i32 @fn() { +entry: + ret i32 10 +} + +define i32 @test_nested2(i32 %tnr) { +; CHECK-LABEL: test_nested2 +; CHECK-NOT: %indvars.iv +; CHECK: %i.0 + +; indvars should not replace the i.0 variable with a new one; SCEVExpander +; should determine that the old one is good to reuse. + +entry: + %res = alloca i32, align 4 + store volatile i32 0, i32* %res, align 4 + %call = call i32 @fn() + br label %for.cond + +for.cond: ; preds = %for.inc6, %entry + %i.0 = phi i32 [ 0, %entry ], [ %inc7, %for.inc6 ] + %cmp = icmp slt i32 %i.0, %call + br i1 %cmp, label %for.body, label %for.cond.cleanup + +for.cond.cleanup: ; preds = %for.cond + br label %for.end8 + +for.body: ; preds = %for.cond + br label %for.cond1 + +for.cond1: ; preds = %for.inc, %for.body + %j.0 = phi i32 [ 0, %for.body ], [ %inc5, %for.inc ] + %cmp2 = icmp slt i32 %j.0, %i.0 + br i1 %cmp2, label %for.body4, label %for.cond.cleanup3 + +for.cond.cleanup3: ; preds = %for.cond1 + br label %for.end + +for.body4: ; preds = %for.cond1 + %0 = load volatile i32, i32* %res, align 4 + %inc = add nsw i32 %0, 1 + store volatile i32 %inc, i32* %res, align 4 + br label %for.inc + +for.inc: ; preds = %for.body4 + %inc5 = add nsw i32 %j.0, 1 + br label %for.cond1 + +for.end: ; preds = %for.cond.cleanup3 + br label %for.inc6 + +for.inc6: ; preds = %for.end + %inc7 = add nsw i32 %i.0, 1 + br label %for.cond + +for.end8: ; preds = %for.cond.cleanup + %1 = load volatile i32, i32* %res, align 4 + %cmp9 = icmp eq i32 %1, 45 + %conv = zext i1 %cmp9 to i32 + ret i32 %conv +}