-bash-3.2$ /usr/local/gcc/bin/gcc -O0 -fsplit-wide-types /tmp/segfault.c -S -o /dev/null /tmp/segfault.c: In function 'segfault': /tmp/segfault.c:4: internal compiler error: Segmentation fault Please submit a full bug report, with preprocessed source if appropriate. See <URL:http://gcc.gnu.org/bugs.html> for instructions.
The lower subreg pass sets regno_reg_rtx[i] to NULL_RTX when splitting register i. regclass() uses PSEUDO_REGNO_MODE(i) which expands to GET_MODE (regno_reg_rtx[i)) and gives the segfault. -- Summary: segfault in regclass() with -O0 -fsplit-wide-types Product: gcc Version: 4.3.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: rtl-optimization AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: rask at sygehus dot dk GCC build triplet: i686-pc-linux-gnu GCC host triplet: i686-pc-linux-gnu GCC target triplet: i686-pc-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32069