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c0f2b8b528
LinearFunctionTestReplace tries to use the *next* indvar to compare against when possible. However, it may be the case that the calculation for the next indvar has NUW/NSW flags and that it may only be safely used inside the loop. Using it in a comparison to calculate the exit condition could result in observing poison. This fixes PR20680. Differential Revision: http://reviews.llvm.org/D5174 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217102 91177308-0d34-0410-b5e6-96231b3b80d8
45 lines
1.3 KiB
LLVM
45 lines
1.3 KiB
LLVM
;RUN: opt -S %s -indvars | FileCheck %s
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; CHECK-LABEL: @foo(
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; CHECK-NOT: %lftr.wideiv = trunc i32 %indvars.iv.next to i16
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; CHECK: %exitcond = icmp ne i32 %indvars.iv, 511
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define void @foo() #0 {
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entry:
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br label %for.body
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for.body: ; preds = %entry, %for.body
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%i.01 = phi i16 [ 0, %entry ], [ %inc, %for.body ]
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%conv2 = sext i16 %i.01 to i32
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call void @bar(i32 %conv2) #1
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%inc = add i16 %i.01, 1
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%cmp = icmp slt i16 %inc, 512
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br i1 %cmp, label %for.body, label %for.end
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for.end: ; preds = %for.body
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ret void
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}
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; Check that post-incrementing the backedge taken count does not overflow.
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; CHECK-LABEL: @postinc(
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; CHECK: icmp eq i32 %indvars.iv, 255
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define i32 @postinc() #0 {
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entry:
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br label %do.body
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do.body: ; preds = %do.body, %entry
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%first.0 = phi i8 [ 0, %entry ], [ %inc, %do.body ]
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%conv = zext i8 %first.0 to i32
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call void @bar(i32 %conv) #1
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%inc = add i8 %first.0, 1
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%cmp = icmp eq i8 %first.0, -1
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br i1 %cmp, label %do.end, label %do.body
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do.end: ; preds = %do.body
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ret i32 0
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}
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declare void @bar(i32)
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attributes #0 = { nounwind uwtable }
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attributes #1 = { nounwind }
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