Re: GNU Guile 2.1.5 released (beta)

[Matt Wette]

> On Jan 8, 2017, at 3:01 PM, Andy Wingo <address@hidden> wrote:
> 
> On Tue 20 Dec 2016 23:58, Matt Wette <address@hidden> writes:
> 
>> With the patch below I can get through all the tests on my Mac (macOS 
>> 10.12.2) if I use default flags (i.e., -g -O2) and gcc-4.9 (now verifying 
>> also w/ gcc-6.2). The patch is a hack to
>> get around an apparent optimization that thinks the sine of -0.0 is +0.0. 
>> 
>> Matt
>> 
>> --- libguile/numbers.c-orig 2016-11-21 13:56:23.000000000 -0800
>> +++ libguile/numbers.c 2016-12-20 14:43:58.000000000 -0800
>> @@ -9099,6 +9099,9 @@
>> #undef FUNC_NAME
>> 
>> SCM
>> +#ifdef __APPLE__
>> +__attribute__((optimize("O0")))
>> +#endif
>> scm_c_make_polar (double mag, double ang)
>> {
>> double s, c;
> 
> Aaah, thank you for tracking this one down!  So.  I assume that with GCC
> (any version) everything is fine.  This is apparently an optimization in
> LLVM.  But... is LLVM wrong, or are we wrong?  I guess LLVM is wrong,
> right, since the result depends on the optimization level?  Surely we
> should be able to produce a nice compiler bug report out of this :)

I’m still not sure this is a bug.  I have a gut feeling there are some 
lingering issues on the Mac port.  I think this breaks w/ gcc also.  I will try 
again to verify.

Matt