cudcv@warwick.ac.uk (Rob McMahon) (09/28/88)
GCC 1.28, Gould PN6000 While trying to simplify combinations like (zero_extend:DI (and:SI (reg:SI ...) (const_int ...))), subst will call gen_lowpart_for_combine with mode DImode, which calls gen_lowpart, which aborts. I believe the problem is that FAKE_EXTEND_SAFE_P should not accept modes bigger than a word. Rejecting them prevents subst from trying these simplifications, and it seems you could only do this fake extension to DImode from a stack slot, you may not be able to extend any old register. Suggested fix: RCS file: combine.c,v retrieving revision 1.9 diff -c -r1.9 combine.c *** /tmp/,RCSt1a01177 Wed Sep 28 00:43:12 1988 --- combine.c Tue Sep 27 23:17:23 1988 *************** *** 730,737 **** If not for that, MEM's would very rarely be safe. */ #define FAKE_EXTEND_SAFE_P(MODE, FROM) \ ! (GET_CODE (FROM) == REG || GET_CODE (FROM) == SUBREG \ ! || GET_CODE (FROM) == MEM) if (x == from) return to; --- 730,738 ---- If not for that, MEM's would very rarely be safe. */ #define FAKE_EXTEND_SAFE_P(MODE, FROM) \ ! (GET_MODE_SIZE (MODE) <= UNITS_PER_WORD \ ! && (GET_CODE (FROM) == REG || GET_CODE (FROM) == SUBREG \ ! || GET_CODE (FROM) == MEM)) if (x == from) return to; Rob -- UUCP: ...!mcvax!ukc!warwick!cudcv PHONE: +44 203 523037 JANET: cudcv@uk.ac.warwick ARPA: cudcv@warwick.ac.uk Rob McMahon, Computing Services, Warwick University, Coventry CV4 7AL, England