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Re: [PATCH 1/8] Document signaling for min, max and ltgt operations
> Am 20.08.2019 um 17:32 schrieb Segher Boessenkool <segher@kernel.crashing.org>:
>
> On Tue, Aug 20, 2019 at 05:19:46PM +0200, Ilya Leoshkevich wrote:
>>> Am 20.08.2019 um 17:04 schrieb Segher Boessenkool <segher@kernel.crashing.org>:
>>> The < and > operators separately already can cause exceptions, unless
>>> you use -fno-trapping-math, in which case you cannot have LTGT at all.
>>
>> Hmm, I've just tried compiling:
>>
>> int foo(float a, float b) { return ((a < b) || (a > b)); }
>>
>> with -ftrapping-math and -fno-trapping-math with gcc 8.0.1, and got LTGT
>> on tree and rtl levels in both cases:
>>
>> 232t.optimized: _1 = a_2(D) <> b_3(D);
>> 312r.final: (if_then_else:SI (ltgt (reg:CCS 33 %cc)
>
> Hrm, it seems to need -ffinite-math-only, even? Or just -ffast-math
> of course. (That'll teach me to post without testing for another year
> or two, sorry!)
Ah, that's correct, and I have even added s390 tests for this: with
-ffinite-math-only the generated code is more "straightforward". I
should update the commit message, but this isn't affecting the manual
update itself, right?