[PATCH] D70450: [AArch64] Teach Load/Store optimizier to rename store operands for pairing.

Tue Jan 21 11:07:28 PST 2020

hans added a comment.

In D70450#1793700 <https://reviews.llvm.org/D70450#1793700>, @phosek wrote:

> In D70450#1793699 <https://reviews.llvm.org/D70450#1793699>, @phosek wrote:
>
> > This change seems to have broken `-ffixed-xX`, we've noticed that our kernel started crashing with tip-of-tree Clang. After debugging, we found out that compiler would generate stores to x15 even though we compile with `-ffixed-x15` which breaks the kernel because x15 is used to store per-cpu state. Would it be possible to revert or fix this issue ASAP please?
>
>
> I've filed PR44358 to track this and I've also included a reproducer in that bug.

In addition to that bug, which was fixed in d269255b95151dcd232c8856206b7e79d70eda29 <https://reviews.llvm.org/rGd269255b95151dcd232c8856206b7e79d70eda29>, we've bisected another miscompile in Chromium (on Android) to this revision. We don't have a reproducer yet, but figured we should send a heads up in case anyone else was seeing problems too.

The Chromium bug is here: https://bugs.chromium.org/p/chromium/issues/detail?id=1037912

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https://reviews.llvm.org/D70450