------- Comment #37 from rguenth at gcc dot gnu dot org 2007-03-30 10:01 ------- The (target) difference seems to be that I get (on x86_64)
mask_lo_45 = 0x0ffffffffffffffff >> D.33492_44; with a value range of [0,64] for D.33492_44 and a resulting value range of [0, +INF] for mask_lo_45, not [+INF, +INF] (which is wrong). Note that I get the same correct behavior iff changing HWI to 32/64bits and using -m32. This is the testcase I'm looking at: #define HOST_WIDE_INT long #define HOST_BITS_PER_WIDE_INT (8*8) int sign_bit_p (int width, HOST_WIDE_INT val_hi, unsigned HOST_WIDE_INT val_lo) { unsigned HOST_WIDE_INT mask_lo, lo; HOST_WIDE_INT mask_hi, hi; if (width > HOST_BITS_PER_WIDE_INT) { hi = (unsigned HOST_WIDE_INT) 1 << (width - HOST_BITS_PER_WIDE_INT - 1); lo = 0; mask_hi = ((unsigned HOST_WIDE_INT) -1 >> (2 * HOST_BITS_PER_WIDE_INT - width)); mask_lo = -1; } else { hi = 0; lo = (unsigned HOST_WIDE_INT) 1 << (width - 1); mask_hi = 0; mask_lo = ((unsigned HOST_WIDE_INT) -1 >> (HOST_BITS_PER_WIDE_INT - width)); } if ((val_hi & mask_hi) == hi && (val_lo & mask_lo) == lo) return 1; return 0; } can you confirm that this one is miscompiled? I'll try to build a cross compiler now. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31169