[PATCH] D81632: Fix undefined behavior in PeepholeOptimizer.

[Bill Wendling via Phabricator via llvm-commits]

void added a comment.

In D81632#2092363 <https://reviews.llvm.org/D81632#2092363>, @linzj wrote:

> > I think SubIdx is supposed to be set by TII->isCoalescableExtInstr(). If it's not doing that, then the error's probably in that call and not in this function.
>
> Then most target instr infos need to patch.
>
> >   A test case that shows the problem would also be good.
>
> valgrind shows me this bug. I don't think any testcase is able to reproduce an expected value in this circumstance.


Which platform did you run valgrind on? The x86 platform should set SubIdx on all paths through it...


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  https://reviews.llvm.org/D81632/new/

https://reviews.llvm.org/D81632