* -O3 failures with ? vectorization in gcc 4.9
@ 2014-01-10 13:14 Tim Prince
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From: Tim Prince @ 2014-01-10 13:14 UTC (permalink / raw)
To: gcc-help
I get good results with -march=core-avx2 -O2 -ftree-vectorize
-finline-functions -funswitch-loops -fpredictive-commoning
-fgcse-after-reload -ftree-slp-vectorize -ftree-partial-pre
-fipa-cp-clone, arrived at by trying the options listed as being enabled
at -O3 and removing those which fail at run time. Is this the
recommended way to go, or should I file a PR about one or two cases
which fail at -O3?
When running under gdb with -O3, a segfault is reported in separately
compiled code which isn't directly affected by these options. When
running outside gdb, the application hangs when it reaches a vectorized
loop containing ? operator.
It seems that -fvect-cost-model is not the only part of -O3 which
produces failure.
--
Tim Prince
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