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-O3 and -ftree-vectorize
- From: Uros Bizjak <ubizjak at gmail dot com>
- To: GCC Development <gcc at gcc dot gnu dot org>
- Cc: Jakub Jelinek <jakub at redhat dot com>, Richard Biener <rguenther at suse dot de>
- Date: Thu, 6 Feb 2014 19:51:33 +0100
- Subject: -O3 and -ftree-vectorize
- Authentication-results: sourceware.org; auth=none
Hello!
4.9 does not enable -ftree-vectorize for -O3 (and Ofast) anymore. Is
this intentional?
$/ssd/uros/gcc-build/gcc/xgcc -B /ssd/uros/gcc-build/gcc -O3 -Q
--help=optimizers
...
-ftree-vectorize [disabled]
...
This is the reason for low scores on SciMark v2.0 as conducted by
Phoronix. Please see comment #18 in [1].
[1] http://phoronix.com/forums/showthread.php?95147-Clang-s-Competition-For-GCC-On-Intel-Haswell/page2
Uros.