Dorit Nuzman wrote: >> H. J. Lu wrote: >> >>> Why don't we turn on vectorizer at -O3 or even -O2, depending on >>> ISA? I added -ftree-vectorize to BOOT_CFLAGS on x86-64. According to >>> -ftree-vectorizer-verbose=1, there are 82 loops vectorized in >>> gcc source. There are no regressions. There are not much changes >>> in bootstrap time as well as "make check" time. >> We have about two dozen cases of packages that break when >> -ftree-vectorize is used. I'm sure there are several more as we tend to >> discourage such bug reports. >> > If you could take the time to find the reduced testcases and file PRs for > these, that would be most appreciated.
I believe the majority of them can be traced back to PR 25413. For example building zlib with -O2 -march=pentium4 -ftree-vectorize will cause several apps that link to it (firefox, openoffice, poppler, etc.) to segfault. The vectorizer generates movdqa instructions with datarefs that are not aligned on a 16 byte boundary. Other than that, I went through the rest of our -ftree-vectorize bugs this morning and found that many of them have been fixed in 4.2, so the situation is much better than I originally thought. -- dirtyepic salesman said this vacuum's guaranteed gentoo org it could suck an ancient virus from the sea 9B81 6C9F E791 83BB 3AB3 5B2D E625 A073 8379 37E8 (0x837937E8)
