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author | Jean-Luc Duprat <jduprat@apple.com> | 2013-05-22 18:29:31 +0000 |
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committer | Jean-Luc Duprat <jduprat@apple.com> | 2013-05-22 18:29:31 +0000 |
commit | 0dda6f168c657e6e8eb88ed31b63c59e7a1a504a (patch) | |
tree | 78e76083eb5d82d7c8267ecea8732e5b4de8c726 /llvm/lib/CodeGen/MachineCopyPropagation.cpp | |
parent | d8fb478b36377ddd2ac11f73906b5a350f9cdd4c (diff) | |
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This is an update to a previous commit (r181216).
The earlier change list introduced the following inst combines:
B * (uitofp i1 C) —> select C, B, 0
A * (1 - uitofp i1 C) —> select C, 0, A
select C, 0, B + select C, A, 0 —> select C, A, B
Together these 3 changes would simplify :
A * (1 - uitofp i1 C) + B * uitofp i1 C
down to :
select C, B, A
In practice we found that the first two substitutions can have a
negative effect on performance, because they reduce opportunities to
use FMA contractions; between the two options FMAs are often the
better choice. This change list amends the previous one to enable
just these inst combines:
select C, B, 0 + select C, 0, A —> select C, B, A
A * (1 - uitofp i1 C) + B * uitofp i1 C —> select C, B, A
llvm-svn: 182499
Diffstat (limited to 'llvm/lib/CodeGen/MachineCopyPropagation.cpp')
0 files changed, 0 insertions, 0 deletions