compiler error with comma-separated expressions

[David Goodwin <goodwin@xxxxxxxxxxxxx>]

This code fails at -O0 but passes at -O2.

[test] sgicc -S paren.c

### Assertion failure at line 1012 of ../../be/com/wn_verifier.cxx:
### Compiler Error in file paren.c during Lowering phase:
### field_id and descriptor type are inconsistent
sgicc INTERNAL ERROR:  ia64/lib/gcc-lib/ia64-sgi-linux/sgicc-1.0/be returned 
non-zero status 1



typedef struct
{
  int a;
  int b;
  int c;
} astruct;

int g;
astruct *gs;

void paren (astruct *as)
{
  (g = 1, *gs = *as);
}