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Re: How to get GCC on par with ICC?
- From: Joseph Myers <joseph at codesourcery dot com>
- To: Jeff Law <law at redhat dot com>
- Cc: Wilco Dijkstra <Wilco dot Dijkstra at arm dot com>, "mjambor at suse dot cz" <mjambor at suse dot cz>, "gcc at gcc dot gnu dot org" <gcc at gcc dot gnu dot org>, nd <nd at arm dot com>, Steve Ellcey <sellcey at cavium dot com>, Richard Biener <richard dot guenther at gmail dot com>, "pmenzel+gcc dot gnu dot org at molgen dot mpg dot de" <pmenzel+gcc dot gnu dot org at molgen dot mpg dot de>
- Date: Fri, 15 Jun 2018 17:03:28 +0000
- Subject: Re: How to get GCC on par with ICC?
- References: <DB5PR08MB10302D16370CB306B77A6104837C0@DB5PR08MB1030.eurprd08.prod.outlook.com> <dcc58008-4c66-c8f5-e427-d22be0f1ef64@redhat.com>
On Fri, 15 Jun 2018, Jeff Law wrote:
> And resolution on -fno-math-errno as the default. Setting errno can be
> more expensive than people realize.
I don't think I saw any version of the -fno-math-errno patch proposal that
included the testsuite updates I'd expect. Certainly
gcc.dg/torture/pr68264.c tests libm functions setting errno and would need
to use -fmath-errno explicitly, but it seems likely there are other tests
involving built-in functions that in fact only test what they're intended
to test given -fmath-errno; tests using libm functions without explicit
-ffast-math / -fmath-errno / -fno-math-errno would need review (and there
should be new tests for optimizations that are only valid given
-fno-math-errno).
--
Joseph S. Myers
joseph@codesourcery.com