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[Bug target/17619] Non-optimal code for -mfpmath=387,sse
- From: "bangerth at dealii dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 1 Dec 2004 20:49:26 -0000
- Subject: [Bug target/17619] Non-optimal code for -mfpmath=387,sse
- References: <20040922191917.17619.bangerth@dealii.org>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Additional Comments From bangerth at dealii dot org 2004-12-01 20:49 -------
In reply to comment #6:
> Please note, that we should return the result in fp reg, so final flds is
> needed in any case. I think, this code is optimal.
Almost, or at least I believe so. If we assume that all the operations
with xmm registers cost the same as with the floating point stack, then
the result of -mfpmath=387,sse requires one stack push and pop more than
the result of -mfpmath=387. The compiler should recognize this and then
simply not use the sse registers at all.
I will open a new PR for this, and another one for the vectorization issue.
Thanks for now
Wolfgang
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What |Removed |Added
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Status|NEW |RESOLVED
Resolution| |FIXED
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17619