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| author | Richard Biener <rguenther@suse.de> | 2022-01-24 15:26:46 +0100 |
|---|---|---|
| committer | Richard Biener <rguenther@suse.de> | 2022-02-04 12:54:35 +0100 |
| commit | 24c72fb0eedfe7c67f9b15aa31b474a999cc4723 (patch) | |
| tree | e37bf8a72449e7e5cc59a280b791c037f681d5f9 /gcc | |
| parent | 38948b77dbc16f4c6cf6cff8661bab699b306f03 (diff) | |
| download | gcc-24c72fb0eedfe7c67f9b15aa31b474a999cc4723.zip gcc-24c72fb0eedfe7c67f9b15aa31b474a999cc4723.tar.gz gcc-24c72fb0eedfe7c67f9b15aa31b474a999cc4723.tar.bz2 | |
Adjust LSHIFT_EXPR handling of multiple_of_p
This removes the odd check of size_type_node when handling left-shifts
as multiplications of 1 << N and instead uses the type as specified.
It also moves left-shift handling next to multiplications where it
semantically belongs.
2022-01-24 Richard Biener <rguenther@suse.de>
* fold-const.cc (multiple_of_p): Re-write and move LSHIFT_EXPR
handling.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/fold-const.cc | 33 |
1 files changed, 16 insertions, 17 deletions
diff --git a/gcc/fold-const.cc b/gcc/fold-const.cc index 8fc01cd..12732d3 100644 --- a/gcc/fold-const.cc +++ b/gcc/fold-const.cc @@ -14079,7 +14079,7 @@ int multiple_of_p (tree type, const_tree top, const_tree bottom) { gimple *stmt; - tree t1, op1, op2; + tree op1, op2; if (operand_equal_p (top, bottom, 0)) return 1; @@ -14125,6 +14125,21 @@ multiple_of_p (tree type, const_tree top, const_tree bottom) return (multiple_of_p (type, TREE_OPERAND (top, 1), bottom) || multiple_of_p (type, TREE_OPERAND (top, 0), bottom)); + case LSHIFT_EXPR: + /* Handle X << CST as X * (1 << CST) and only process the constant. */ + if (TREE_CODE (TREE_OPERAND (top, 1)) == INTEGER_CST) + { + op1 = TREE_OPERAND (top, 1); + if (wi::to_widest (op1) < TYPE_PRECISION (type)) + { + wide_int mul_op + = wi::one (TYPE_PRECISION (type)) << wi::to_wide (op1); + return multiple_of_p (type, + wide_int_to_tree (type, mul_op), bottom); + } + } + return 0; + case MINUS_EXPR: /* It is impossible to prove if op0 - op1 is multiple of bottom precisely, so be conservative here checking if both op0 and op1 @@ -14144,22 +14159,6 @@ multiple_of_p (tree type, const_tree top, const_tree bottom) return (multiple_of_p (type, op1, bottom) && multiple_of_p (type, TREE_OPERAND (top, 0), bottom)); - case LSHIFT_EXPR: - if (TREE_CODE (TREE_OPERAND (top, 1)) == INTEGER_CST) - { - op1 = TREE_OPERAND (top, 1); - /* const_binop may not detect overflow correctly, - so check for it explicitly here. */ - if (wi::gtu_p (TYPE_PRECISION (TREE_TYPE (size_one_node)), - wi::to_wide (op1)) - && (t1 = fold_convert (type, - const_binop (LSHIFT_EXPR, size_one_node, - op1))) != 0 - && !TREE_OVERFLOW (t1)) - return multiple_of_p (type, t1, bottom); - } - return 0; - CASE_CONVERT: /* Can't handle conversions from non-integral or wider integral type. */ if ((TREE_CODE (TREE_TYPE (TREE_OPERAND (top, 0))) != INTEGER_TYPE) |