[MacPorts] #60356: MacPorts gcc 9.3.0 internal compiler error: Segmentation fault: 11 - not seen with Homebrew gcc 9.3.0

[MacPorts]

#60356: MacPorts gcc 9.3.0 internal compiler error: Segmentation fault: 11 - not
seen with Homebrew gcc 9.3.0
-----------------------------+--------------------
  Reporter:  attiliodefalco  |      Owner:  (none)
      Type:  defect          |     Status:  new
  Priority:  Normal          |  Milestone:
 Component:  ports           |    Version:
Resolution:                  |   Keywords:
      Port:  gcc9            |
-----------------------------+--------------------
Description changed by mf2k:

Old description:

> The following code fails to compile with MacPorts gcc 9.3.0 but not
> Homebrew gcc 9.3.0
>
> {{{
> #include <math.h>
>  double vec_dist ()
>  {double r=0;
>  return sqrt(r);
>  }
> }}}
>
> And compile with:
>
>     gcc -O2 -ffast-math -c test.c
>

> The output is:
>
> {{{
> test.c: In function 'vec_dist':
> test.c:6:1: internal compiler error: Segmentation fault: 11
> }
> ^
> test.c:6:1: internal compiler error: Abort trap: 6
> gcc: internal compiler error: Abort trap: 6 (program cc1)
> }}}
>

>

>
> This reproduces on my 4-year old laptop, but not my 5-year old mini.
> Both are currently running 10.15.4 (usually the mini runs betas) and
> have gcc 9.3.0 from MacPorts.  On the laptop, this segfaults the
> compiler when compiled with '-O2 -ffastmath':
>
> extern double sqrt(double);
> double mad_vec_dist () { double r=0; return sqrt(r); }
>
> (note that I removed the include of math.h).  Changing sqrt() to sin()
> also segfaults.  However, this compiles fine:
>
> extern double trqs(double);
> double vec_dist () { double r=0; return trqs(r); }
>
> and the ones that segfault the compiler don't segfault if I add the
> '-fno-builtin' flag--so it's something about the optimization of the
> builtin math functions that are enabled by -ffastmath.  This is
> likely actually a bug in the upstream gcc but I don't see the segfault
> with Homebrew gcc 9.3 (or even on CentOS 7 gcc 9.3).
>

> Please let me know if I should notify GNU, as well.
>
> Thanks!
>
> Attilio

New description:

 The following code fails to compile with MacPorts gcc 9.3.0 but not
 Homebrew gcc 9.3.0

 {{{
 #include <math.h>
  double vec_dist ()
  {double r=0;
  return sqrt(r);
  }
 }}}

 And compile with:

     gcc -O2 -ffast-math -c test.c


 The output is:

 {{{
 test.c: In function 'vec_dist':
 test.c:6:1: internal compiler error: Segmentation fault: 11
 }
 ^
 test.c:6:1: internal compiler error: Abort trap: 6
 gcc: internal compiler error: Abort trap: 6 (program cc1)
 }}}

 This reproduces on my 4-year old laptop, but not my 5-year old mini.
 Both are currently running 10.15.4 (usually the mini runs betas) and
 have gcc 9.3.0 from MacPorts.  On the laptop, this segfaults the
 compiler when compiled with '-O2 -ffastmath':
 {{{
 extern double sqrt(double);
 double mad_vec_dist () { double r=0; return sqrt(r); }
 }}}
 (note that I removed the include of math.h).  Changing sqrt() to sin()
 also segfaults.  However, this compiles fine:
 {{{
 extern double trqs(double);
 double vec_dist () { double r=0; return trqs(r); }
 }}}
 and the ones that segfault the compiler don't segfault if I add the
 '-fno-builtin' flag--so it's something about the optimization of the
 builtin math functions that are enabled by -ffastmath.  This is
 likely actually a bug in the upstream gcc but I don't see the segfault
 with Homebrew gcc 9.3 (or even on CentOS 7 gcc 9.3).

 Please let me know if I should notify GNU, as well.

 Thanks!

 Attilio

--

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Ticket URL: <https://trac.macports.org/ticket/60356#comment:2>
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