commit 2956e92bdfe148986ae7cd18ae4afb48a7c744f9
author Benjamin Kramer <benny.kra@googlemail.com> Wed Apr 14 16:37:38 2021 +0200
committer Copybara-Service <copybara-worker@google.com> Fri Apr 16 12:40:31 2021 -0700
tree 14f198f97cc44e3da6d752dd83ab6f91690bfa8a
parent b76c110c7c80ba0231a7e137b647e636df674f91

[Instcombine] Disable memcpy of alloca bypass for instruction sources

This transformation is fundamentally broken when it comes to dominance,
it just happened to work when the source of the memcpy can be moved into
the place of the alloca. The bug shows up a lot more often since
077bff39d46364035a5dcfa32fc69910ad0975d0 allows the source to be a
switch.

It would be possible to check dominance of the source and all its
operands, but that seems very heavy for instcombine.

GitOrigin-RevId: cf4161673c7e7c7c57d8115468bfcc9988f43d36