diff options
| author | Richard Guenther <rguenther@suse.de> | 2012-05-15 13:18:32 +0000 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2012-05-15 13:18:32 +0000 |
| commit | 8c1f1d428facaaa17c3ce21cfef418948e3c52fa (patch) | |
| tree | 83af2b9b3ebecd6808484f834799b5c45641c689 /gcc/tree-vrp.c | |
| parent | 1ce499ae1a08089cbafa46e9577de7096298f10a (diff) | |
| download | gcc-8c1f1d428facaaa17c3ce21cfef418948e3c52fa.zip gcc-8c1f1d428facaaa17c3ce21cfef418948e3c52fa.tar.gz gcc-8c1f1d428facaaa17c3ce21cfef418948e3c52fa.tar.bz2 | |
re PR tree-optimization/53355 (Autovectorization of a simple loop could be improved.)
2012-05-15 Richard Guenther <rguenther@suse.de>
PR tree-optimization/53355
* tree-vrp.c (extract_range_from_binary_expr_1): Handle LSHIFT_EXPRs
by constants.
* gcc.dg/tree-ssa/vrp67.c: New testcase.
From-SVN: r187535
Diffstat (limited to 'gcc/tree-vrp.c')
| -rw-r--r-- | gcc/tree-vrp.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c index 72c647f..4dc942c 100644 --- a/gcc/tree-vrp.c +++ b/gcc/tree-vrp.c @@ -2403,6 +2403,7 @@ extract_range_from_binary_expr_1 (value_range_t *vr, && code != ROUND_DIV_EXPR && code != TRUNC_MOD_EXPR && code != RSHIFT_EXPR + && code != LSHIFT_EXPR && code != MIN_EXPR && code != MAX_EXPR && code != BIT_AND_EXPR @@ -2596,6 +2597,40 @@ extract_range_from_binary_expr_1 (value_range_t *vr, extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1); return; } + else if (code == LSHIFT_EXPR) + { + /* If we have a LSHIFT_EXPR with any shift values outside [0..prec-1], + then drop to VR_VARYING. Outside of this range we get undefined + behavior from the shift operation. We cannot even trust + SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl + shifts, and the operation at the tree level may be widened. */ + if (vr1.type != VR_RANGE + || !value_range_nonnegative_p (&vr1) + || TREE_CODE (vr1.max) != INTEGER_CST + || compare_tree_int (vr1.max, TYPE_PRECISION (expr_type) - 1) == 1) + { + set_value_range_to_varying (vr); + return; + } + + /* We can map shifts by constants to MULT_EXPR handling. */ + if (range_int_cst_singleton_p (&vr1)) + { + value_range_t vr1p = { VR_RANGE, NULL_TREE, NULL_TREE, NULL }; + vr1p.min + = double_int_to_tree (expr_type, + double_int_lshift (double_int_one, + TREE_INT_CST_LOW (vr1.min), + TYPE_PRECISION (expr_type), + false)); + vr1p.max = vr1p.min; + extract_range_from_multiplicative_op_1 (vr, MULT_EXPR, &vr0, &vr1p); + return; + } + + set_value_range_to_varying (vr); + return; + } else if (code == TRUNC_DIV_EXPR || code == FLOOR_DIV_EXPR || code == CEIL_DIV_EXPR |