44 lines
1.5 KiB
LLVM
44 lines
1.5 KiB
LLVM
; RUN: opt %s -indvars -loop-instsimplify -loop-reduce
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; We are only checking that there is no crash!
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; https://bugs.llvm.org/show_bug.cgi?id=37936
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; The problem is as follows:
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; 1. indvars marks %dec as NUW.
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; 2. loop-instsimplify runs instsimplify, which constant-folds %dec to -1
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; 3. loop-reduce tries to do some further modification, but crashes
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; with an type assertion in cast, because %dec is no longer an Instruction,
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; even though the SCEV data indicated it was.
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; If the runline is split into two, i.e. -indvars -loop-instsimplify first, that
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; stored into a file, and then -loop-reduce is run on that, there is no crash.
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; So it looks like the problem is due to -loop-instsimplify not discarding SCEV.
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target datalayout = "n16"
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@a = external global i16, align 1
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define void @f1() {
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entry:
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br label %for.cond
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for.cond: ; preds = %land.end, %entry
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%c.0 = phi i16 [ 0, %entry ], [ %dec, %land.end ]
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br i1 undef, label %for.body, label %for.cond.cleanup
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for.cond.cleanup: ; preds = %for.cond
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ret void
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for.body: ; preds = %for.cond
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%0 = load i16, i16* @a, align 1
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%cmp = icmp sgt i16 %0, %c.0
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br i1 %cmp, label %land.rhs, label %land.end
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land.rhs: ; preds = %for.body
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unreachable
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land.end: ; preds = %for.body
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%dec = add nsw i16 %c.0, -1
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br label %for.cond
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}
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