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