diff options
Diffstat (limited to 'gcc/tree-vrp.c')
| -rw-r--r-- | gcc/tree-vrp.c | 53 |
1 files changed, 52 insertions, 1 deletions
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c index cb1a3e5..cf50e90 100644 --- a/gcc/tree-vrp.c +++ b/gcc/tree-vrp.c @@ -2865,8 +2865,59 @@ extract_range_from_binary_expr_1 (value_range *vr, &may_be_nonzero1, &must_be_nonzero1); + if (code == BIT_AND_EXPR || code == BIT_IOR_EXPR) + { + value_range *vr0p = NULL, *vr1p = NULL; + if (range_int_cst_singleton_p (&vr1)) + { + vr0p = &vr0; + vr1p = &vr1; + } + else if (range_int_cst_singleton_p (&vr0)) + { + vr0p = &vr1; + vr1p = &vr0; + } + /* For op & or | attempt to optimize: + [x, y] op z into [x op z, y op z] + if z is a constant which (for op | its bitwise not) has n + consecutive least significant bits cleared followed by m 1 + consecutive bits set immediately above it and either + m + n == precision, or (x >> (m + n)) == (y >> (m + n)). + The least significant n bits of all the values in the range are + cleared or set, the m bits above it are preserved and any bits + above these are required to be the same for all values in the + range. */ + if (vr0p && range_int_cst_p (vr0p)) + { + wide_int w = vr1p->min; + int m = 0, n = 0; + if (code == BIT_IOR_EXPR) + w = ~w; + if (wi::eq_p (w, 0)) + n = TYPE_PRECISION (expr_type); + else + { + n = wi::ctz (w); + w = ~(w | wi::mask (n, false, w.get_precision ())); + if (wi::eq_p (w, 0)) + m = TYPE_PRECISION (expr_type) - n; + else + m = wi::ctz (w) - n; + } + wide_int mask = wi::mask (m + n, true, w.get_precision ()); + if (wi::eq_p (mask & vr0p->min, mask & vr0p->max)) + { + min = int_const_binop (code, vr0p->min, vr1p->min); + max = int_const_binop (code, vr0p->max, vr1p->min); + } + } + } + type = VR_RANGE; - if (code == BIT_AND_EXPR) + if (min && max) + /* Optimized above already. */; + else if (code == BIT_AND_EXPR) { min = wide_int_to_tree (expr_type, must_be_nonzero0 & must_be_nonzero1); |