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| author | Nikita Popov <nikita.ppv@gmail.com> | 2020-01-13 18:57:14 +0100 |
|---|---|---|
| committer | Nikita Popov <nikita.ppv@gmail.com> | 2020-01-14 20:45:13 +0100 |
| commit | 65c0805be523445d7ad0f12e90f53648e1ae9f84 (patch) | |
| tree | c94a2b004367e40c29a8b67f13d5afba3700d37c /lldb/packages/Python/lldbsuite/test/plugins/builder_darwin.py | |
| parent | b4dd928ffbb8232d6909b640d3affcd531681ffb (diff) | |
| download | bcm5719-llvm-65c0805be523445d7ad0f12e90f53648e1ae9f84.tar.gz bcm5719-llvm-65c0805be523445d7ad0f12e90f53648e1ae9f84.zip | |
[InstCombine] Fix infinite loop due to bitcast <-> phi transforms
Fix for https://bugs.llvm.org/show_bug.cgi?id=44245.
The optimizeBitCastFromPhi() and FoldPHIArgOpIntoPHI() end up
fighting against each other, because optimizeBitCastFromPhi()
assumes that bitcasts of loads will get folded. This doesn't
happen here, because a dangling phi node prevents the one-use
fold in https://github.com/llvm/llvm-project/blob/master/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp#L620-L628 from triggering.
This patch fixes the issue by explicitly performing the load
combine as part of the bitcast of phi transform. Other attempts
to force the load to be combined first were ultimately too
unreliable.
Differential Revision: https://reviews.llvm.org/D71164
Diffstat (limited to 'lldb/packages/Python/lldbsuite/test/plugins/builder_darwin.py')
0 files changed, 0 insertions, 0 deletions
