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| author | Max Kazantsev <mkazantsev@azul.com> | 2021-04-07 13:14:53 +0700 |
|---|---|---|
| committer | Max Kazantsev <mkazantsev@azul.com> | 2021-04-07 13:55:17 +0700 |
| commit | fee330824a2b3d7e502a27e1464c418a4663d7a3 (patch) | |
| tree | 1473468900540340ace1e7781752f2d097d5a024 /clang/lib/Basic/SourceManager.cpp | |
| parent | 000cf84cf1bb2f5475600737c16c3ccf43096f58 (diff) | |
| download | llvm-fee330824a2b3d7e502a27e1464c418a4663d7a3.zip llvm-fee330824a2b3d7e502a27e1464c418a4663d7a3.tar.gz llvm-fee330824a2b3d7e502a27e1464c418a4663d7a3.tar.bz2 | |
[SCEV] Fix false-positive recognition of simple recurrences. PR49856
A value from reachable block may come to a Phi node as its input from
unreachable block. This may confuse matchSimpleRecurrence which
has no access to DomTree and can falsely recognize something as a recurrency
because of this effect, as the attached test shows.
Patch `ae7b1e` deals with half of this problem, but it only accounts from
the case when an unreachable instruction comes to Phi as an input.
This patch provides a generalization by checking that no Phi block's
predecessor is unreachable (no matter what the input is).
Differential Revision: https://reviews.llvm.org/D99929
Reviewed By: reames
Diffstat (limited to 'clang/lib/Basic/SourceManager.cpp')
0 files changed, 0 insertions, 0 deletions