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Re: [PATCH, middle-end]: Fix PR78738, unrecognized insn with -ffast-math
- From: Richard Biener <richard dot guenther at gmail dot com>
- To: Uros Bizjak <ubizjak at gmail dot com>
- Cc: "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>, James Greenhalgh <james dot greenhalgh at arm dot com>
- Date: Fri, 9 Dec 2016 11:09:35 +0100
- Subject: Re: [PATCH, middle-end]: Fix PR78738, unrecognized insn with -ffast-math
- Authentication-results: sourceware.org; auth=none
- References: <CAFULd4a0WkL6Li5XZ=Pc_5pC2DZDP_GKDN-2W+4gjDu7tMuAyg@mail.gmail.com>
On Thu, Dec 8, 2016 at 10:44 PM, Uros Bizjak <ubizjak@gmail.com> wrote:
> Hello!
>
> Attached patch fixes fall-out from excess-precision improvements
> patch. As shown in the PR, the code throughout the compiler assumes
> FLAG_PRECISION_FAST when flag_unsafe_math_optimizations flag is in
> effect. The patch puts back two lines, removed by excess-precision
> improvements patch.
>
> 2016-12-08 Uros Bizjak <ubizjak@gmail.com>
>
> PR middle-end/78738
> * toplev.c (init_excess_precision): Initialize flag_excess_precision
> to EXCESS_PRECISION_FAST for flag_unsafe_math_optimizations.
>
> testsuite/ChangeLog:
>
> 2016-12-08 Uros Bizjak <ubizjak@gmail.com>
>
> PR middle-end/78738
> * gcc.target/i386/pr78738.c: New test.
>
> Patch was bootstrapped and regression tested on x86_64-linux-gnu {,-m32}.
>
> OK for mainline?
Hmm, I think it belongs to set_unsafe_math_optimization_flags instead
(and be consistent if -fexcess-precision was manually specified).
Also where do we assume connection between -funsafe-math-optimizations
and FLAG_PRECISION_FAST? We have two flags so we should fix any
user that looks at one but means the other.
Richard.
>
> Uros.