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| author | Duncan Sands <baldrick@free.fr> | 2008-02-13 18:01:53 +0000 |
|---|---|---|
| committer | Duncan Sands <baldrick@free.fr> | 2008-02-13 18:01:53 +0000 |
| commit | d462ba853981d45bf9c777564e79dc9e1c850ca6 (patch) | |
| tree | 7c160428925fb88c8e140a63491831477f3d02e2 /test/C++Frontend | |
| parent | 82f0a09c1036c8651f0aa01d1f635abf9460d9f8 (diff) | |
| download | external_llvm-d462ba853981d45bf9c777564e79dc9e1c850ca6.zip external_llvm-d462ba853981d45bf9c777564e79dc9e1c850ca6.tar.gz external_llvm-d462ba853981d45bf9c777564e79dc9e1c850ca6.tar.bz2 | |
Teach LegalizeTypes how to expand and promote CTLZ,
CTTZ and CTPOP. The expansion code differs from
that in LegalizeDAG in that it chooses to take the
CTLZ/CTTZ count from the Hi/Lo part depending on
whether the Hi/Lo value is zero, not on whether
CTLZ/CTTZ of Hi/Lo returned 32 (or whatever the
width of the type is) for it. I made this change
because the optimizers may well know that Hi/Lo
is zero and exploit it. The promotion code for
CTTZ also differs from that in LegalizeDAG: it
uses an "or" to get the right result when the
original value is zero, rather than using a compare
and select. This also means the value doesn't
need to be zero extended.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47075 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test/C++Frontend')
0 files changed, 0 insertions, 0 deletions