The mainline compiler (trunk revision 138833) fails to compile the test case below with -O1:
foo.c:24: internal compiler error: in build2_stat, at tree.c:3257 static union { char buf[12 * sizeof (long long)]; } u; int main () { int off, len, i; char *p, *q; for (off = 0; off < (sizeof (long long)); off++) for (len = 1; len < (10 * sizeof (long long)); len++) { for (i = 0; i < (12 * sizeof (long long)); i++) u.buf[i] = 'a'; p = (__extension__ (__builtin_constant_p ('\0') && ('\0') == '\0' ? ({void *__s = (u.buf + off); __s;}) : memset (u.buf + off, '\0', len))); if (p != u.buf + off) abort (); for (i = 0; i < off; i++, q++) if (*q != 'a') abort (); } } -- Summary: ICE in build2_stat, at tree.c:3257 Product: gcc Version: 4.4.0 Status: UNCONFIRMED Keywords: ice-on-valid-code Severity: normal Priority: P3 Component: tree-optimization AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: kkojima at gcc dot gnu dot org GCC target triplet: i686-pc-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37056