https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117420
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |15.0
Last reconfirmed| |2024-11-02
Ever confirmed|0 |1
Status|UNCONFIRMED |NEW
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Before fre:
# RANGE [irange] int [0, 1] MASK 0x1 VALUE 0x0
_3 = (intD.6) _2;
_4 = -_3;
...
# RANGE [irange] int [0, 1] MASK 0x1 VALUE 0x0
_8 = -_3;
The value assigned to _8 is wrong I think.
Before forwprop2:
# RANGE [irange] int [-INF, +INF] MASK 0xfffffffe VALUE 0x0
_12 = _3 * -2;
# RANGE [irange] int [0, 0][2, 2] MASK 0x2 VALUE 0x0
_7 = _12 & 2;
# RANGE [irange] int [0, 1] MASK 0x1 VALUE 0x0
_8 = _7 / 2;
After:
# RANGE [irange] int [0, 1] MASK 0x1 VALUE 0x0
_8 = -_3;
Comes from:
Matching expression match.pd:197, gimple-match-6.cc:22
Matching expression match.pd:2311, gimple-match-5.cc:64
Matching expression match.pd:197, gimple-match-6.cc:22
Matching expression match.pd:2878, gimple-match-8.cc:90
Matching expression match.pd:2883, gimple-match-4.cc:94
Matching expression match.pd:2311, gimple-match-5.cc:64
Applying pattern match.pd:5607, gimple-match-9.cc:17041
Applying pattern match.pd:990, gimple-match-1.cc:4265
Applying pattern match.pd:5508, gimple-match-10.cc:14607
gimple_simplified to _8 = -_3;
/* Simplify (t * u) / v -> t * (u / v) if u is multiple of v. */
/* X / (1 << C) -> X /[ex] (1 << C) if the low C bits of X are clear. */
I think the issue is how with_possible_nonzero_bits2 is defined or its use in
the pattern added by r15-4601-ge2e798b8607401 . It is causing to remove the &2.
