Re: [Bug 254911] lib/msun/ctrig_test fails if compiled with AVX (-mavx) or any CPUSET enabling AVX

[Dimitry Andric]

On 11 Apr 2021, at 03:32, Kevin P. Neal <kpn at neutralgood.org> wrote:
> 
> On Sat, Apr 10, 2021 at 02:04:29PM +0000, bugzilla-noreply at freebsd.org wrote:
>> https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=254911
>> 
>> --- Comment #5 from commit-hook at FreeBSD.org ---
>> A commit in branch main references this bug:
>> 
>> URL:
>> https://cgit.FreeBSD.org/src/commit/?id=bae9fd0b33462e9506c3ac3400089c6dbc4aee8f
>> 
>> commit bae9fd0b33462e9506c3ac3400089c6dbc4aee8f
>> Author:     Dimitry Andric <dim at FreeBSD.org>
>> AuthorDate: 2021-04-10 14:02:49 +0000
>> Commit:     Dimitry Andric <dim at FreeBSD.org>
>> CommitDate: 2021-04-10 14:02:58 +0000
>> 
>>    Only use -fp-exception-behavior=maytrap on x86, for now
>> 
>>    After 3b00222f156d, it turns out that clang only supports strict
>>    floating point semantics for SystemZ and x86 at the moment, while for
>>    other architectures it is still experimental.
>> 
>>    Therefore, only use -fp-exception-behavior=maytrap on x86 for now,
>>    otherwise this option results in "error: overriding currently
>>    unsupported use of floating point exceptions on this target
>>    [-Werror,-Wunsupported-floating-point-opt]" on other architectures.
> 
> I can't remember exactly when, but clang 11 is probably when it gained
> support for PowerPC. Don't hold me to that, though. Keep that on the list
> of changes to check on when upgrading to a newer version of clang. As for
> AArch64, if anyone is working on it they aren't saying anything at all.

Ah yes, with llvm main (llvmorg-13-init-6905-g91248e2db93a) as of today:

% ag -s HasStrictFP
clang/include/clang/Basic/TargetInfo.h
204:  bool HasStrictFP;
595:  virtual bool hasStrictFP() const { return HasStrictFP; }

clang/lib/Basic/TargetInfo.cpp
40:  HasStrictFP = false;

clang/lib/Basic/Targets/SystemZ.h
51:    HasStrictFP = true;

clang/lib/Basic/Targets/PPC.h
87:    HasStrictFP = true;

clang/lib/Basic/Targets/X86.h
151:    HasStrictFP = true;

The PPC StrictFP support got turned on in:

https://github.com/llvm/llvm-project/commit/8ecc8520bc5bc20ae00c13e5ae13f8edbb80642e

on 2020-09-11, so it will be in 12.0.0 release, at least.

Though the commit message still says "Since work for enabling
constrained FP on PowerPC is almost done, we'd like to enable it". No
idea how done it is. :)

-Dimitry

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