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Author SHA1 Message Date
Evgenii Stepanov f9471b0010 Fix MSan false positive due to select folding.
Summary:
Select folding in JumpThreading can create a conditional branch on a
code patch that did not have one in the original program. This is not a
valid transformation in sanitize_memory functions.

Note that JumpThreading does select folding in 3 different places. Two
of them seem safe - they apply to a select instruction in a BB that ends
with an unconditional branch to another BB, which (in turn) ends with a
conditional branch or a switch with the same condition.

Fixes PR45220.

Reviewers: glider, dvyukov, efriedma

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D76332
2020-03-31 15:25:42 -07:00