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LangRef: mention MSan's problem with speculative conditional branches.
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Authored by eugenis on Sep 5 2019, 4:16 PM.

Details

Summary

This short blurb aims to disallow optimizations like we had to revert
(under MSan) in

https://reviews.llvm.org/D21165
https://bugs.llvm.org/show_bug.cgi?id=28054
https://reviews.llvm.org/D67205

Event Timeline

eugenis created this revision.Sep 5 2019, 4:16 PM
Herald added a project: Restricted Project. · View Herald TranscriptSep 5 2019, 4:16 PM
lebedev.ri added inline comments.
llvm/docs/LangRef.rst
3250

s/ex./e.g./

3255–3256

This doesn't parse.
Either "valid ... at least one defined bit", or "invalid ,,, at least one undefined bit"

eugenis updated this revision to Diff 219002.Sep 5 2019, 4:25 PM
eugenis marked 2 inline comments as done.

.

llvm/docs/LangRef.rst
3255–3256

We don't care about executions where the condition is defined.
When it is not, the new code has a side effect, therefore the original code needs to have a side effect too.

efriedma accepted this revision.Sep 5 2019, 4:41 PM

LGTM

This revision is now accepted and ready to land.Sep 5 2019, 4:41 PM
vitalybuka accepted this revision.Sep 5 2019, 5:31 PM
This revision was automatically updated to reflect the committed changes.