[PATCH] D108201: [AggressiveInstCombine] Add logical shift right instr to `TruncInstCombine` DAG

Fri Aug 20 09:50:28 PDT 2021

spatel added a comment.

In D108201#2957620 <https://reviews.llvm.org/D108201#2957620>, @anton-afanasyev wrote:

>> This should repro in a debug build, but might not be visible in release+asserts; I see it when building with clang on macOS, but it doesn't seem to repro on godbolt.
>> I think it's a simple bug and fixed with:
>> dd19f342fa21 <https://reviews.llvm.org/rGdd19f342fa21a7719b17e33243bda5b69507e4a0>
>
> Thank you!

Easy fix, but it does point to a larger problem (for the 3rd time in this patch set...) - we're seeing unsimplified IR, but this pass is not really prepared to handle that. 
Maybe we'll sort this out when we try to make this pass run at -O2 instead of only -O3 (by having it run directly after -instcombine for example).

Repository:
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https://reviews.llvm.org/D108201