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| author | Evgeniy Stepanov <eugeni.stepanov@gmail.com> | 2014-06-25 07:54:58 +0000 |
|---|---|---|
| committer | Evgeniy Stepanov <eugeni.stepanov@gmail.com> | 2014-06-25 07:54:58 +0000 |
| commit | 98726c311b0dc19076bf242973d92ca1858febe7 (patch) | |
| tree | 4f05d831dd12a24b620b5d87772468891b8d8e99 /tools | |
| parent | aa2e057bc108c32529815afb8be4ef090acddd94 (diff) | |
| download | llvm-98726c311b0dc19076bf242973d92ca1858febe7.tar.gz llvm-98726c311b0dc19076bf242973d92ca1858febe7.tar.bz2 llvm-98726c311b0dc19076bf242973d92ca1858febe7.tar.xz | |
[LICM] Don't create more than one copy of an instruction per loop exit block when sinking.
Fixes exponential compilation complexity in PR19835, caused by
LICM::sink not handling the following pattern well:
f = op g
e = op f, g
d = op e
c = op d, e
b = op c
a = op b, c
When an instruction with N uses is sunk, each of its operands gets N
new uses (all of them - phi nodes). In the example above, if a had 1
use, c would have 2, e would have 4, and g would have 8.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211673 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'tools')
0 files changed, 0 insertions, 0 deletions