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author | Benjamin Kramer <benny.kra@googlemail.com> | 2018-06-20 21:12:59 +0000 |
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committer | Benjamin Kramer <benny.kra@googlemail.com> | 2018-06-20 21:12:59 +0000 |
commit | 1d4e79e9472e1d1cb7bd497b17fd9c433bd6c2ed (patch) | |
tree | 2ddd6b1b5556b2d6501de45e9c02b2f1f6f59957 /clang/CMakeLists.txt | |
parent | c8ae87839926f7e15db5c144752e1b4c80b739a3 (diff) |
[Dominators] Simplify child lists and make them deterministic
This fixes an extremely subtle non-determinism that can only be
triggered by an unfortunate alignment of passes. In my case:
- JumpThreading does large dominator tree updates
- CorrelatedValuePropagation preserves domtree now
- LICM codegen depends on the order of children on domtree nodes
The last part is non-deterministic if the update was stored in a set.
But it turns out that the set is completely unnecessary, updates are
deduplicated at an earlier stage so we can just use a vector, which is
both more efficient and doesn't destroy the input ordering.
I didn't manage to get the 240 MB IR file reduced enough, triggering
this bug requires a lot of jump threading, so landing this without a
test case.
Differential Revision: https://reviews.llvm.org/D48392
llvm-svn: 335176
Diffstat (limited to 'clang/CMakeLists.txt')
0 files changed, 0 insertions, 0 deletions