(in mainline) compile the below with -O. A patch follows which I'm fairly sure is right, but I will not be able to run a test cycle until Nov 30. I'll do it then if nobody else has.
$ld/gcc/gccs.fsf.obj/gcc/xgcc -B $ld/gcc/gccs.fsf.obj/gcc/ -O 4347034.c 4347034.c: In function 'main': 4347034.c:5: warning: incompatible implicit declaration of built-in function 'printf' 4347034.c:17: warning: incompatible implicit declaration of built-in function 'printf' 4347034.c:19: internal compiler error: in do_SUBST, at combine.c:470 int main(int argc, char** argv) { if(argc == 1) { printf("Please provide a two char argument\n"); return 0; } const char *buf = argv[1]; unsigned int data = (((unsigned int) buf[0]) << 8) + (unsigned int) buf[1]; if (data & 0x8000) { data &= 0x7fff ; data ^= 0x7fff ; data += 1 ; data *= -1 ; } printf("Data = %d\n", (int) data); return 0; } Index: combine.c =================================================================== --- combine.c (revision 107129) +++ combine.c (working copy) @@ -3346,13 +3346,15 @@ rtx dest = XEXP (SET_DEST (x), 0); enum machine_mode mode = GET_MODE (dest); unsigned HOST_WIDE_INT mask = ((HOST_WIDE_INT) 1 << len) - 1; + rtx or_mask; if (BITS_BIG_ENDIAN) pos = GET_MODE_BITSIZE (mode) - len - pos; + or_mask = GEN_INT (trunc_int_for_mode (src << pos, mode)); if (src == mask) SUBST (SET_SRC (x), - simplify_gen_binary (IOR, mode, dest, GEN_INT (src << pos))); + simplify_gen_binary (IOR, mode, dest, or_mask)); else { rtx negmask = gen_int_mode (~(mask << pos), mode); @@ -3360,7 +3362,7 @@ simplify_gen_binary (IOR, mode, simplify_gen_binary (AND, mode, dest, negmask), - GEN_INT (src << pos))); + or_mask)); } SUBST (SET_DEST (x), dest); -- Summary: Crash in combine Product: gcc Version: 4.1.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: rtl-optimization AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: dalej at gcc dot gnu dot org GCC build triplet: same GCC host triplet: powerpc-apple-darwin GCC target triplet: same http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24930