https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58073
--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
#define shift 4
return ((mask(d) == (0x0 << shift)) ||
(mask(d) == (0x1 << shift)) ||
(mask(d) == (0x2 << shift)));
static inline unsigned mask(const struct dentry *dentry)
{
return dentry->d_flags & (0x7 << shift);
}
ifcombine does:
_4 = _5 & 112; // this was already there.
_8 = _4 == 16;
_7 = _4 == 0;
_9 = _7 | _8;
_10 = _4 == 32;
_11 = _9 | _10;
Which is correct.
reassoc1 does:
_4 = _5 & 112;
_8 = _4 == 16;
_1 = _4 & 4294967279; // -17 or ~16
_13 = _1 == 0;
_7 = _4 == 0;
_10 = _4 == 32;
_11 = _10 | _13;
and that is where it messes up, it misses reassocation of all three ands
together. And _4 & 4294967279 removes bit 7 from the original and.
Final output:
_4 = _5 & 112; // 0b1110000
_1 = _5 & 96; // 0b1100000
_13 = _1 == 0; // 0b0000000
_10 = _4 == 32;// 0b0100000
_11 = _10 | _13;
So we need have another pattern for something like this:
(bit_ior
(cmp (bit_and @0 INTEGER_CST@2) INTEGER_CST@3)
(cmp (bit_and @0 INTEGER_CST@4) INTEGER_CST@5))
And maybe even one like this (which will solve the issue sooner):
(bit_ior
(cmp (bit_and @0 INTEGER_CST@2) INTEGER_CST@3)
(cmp @0 INTEGER_CST@5)))
