[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:
 Keywords:                  |       Port:
----------------------------+--------------------
 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

-- 
Ticket URL: <https://trac.macports.org/ticket/60356>
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