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| author | jakub <jakub@138bc75d-0d04-0410-961f-82ee72b054a4> | 2001-02-23 12:28:07 +0000 |
|---|---|---|
| committer | jakub <jakub@138bc75d-0d04-0410-961f-82ee72b054a4> | 2001-02-23 12:28:07 +0000 |
| commit | 17e3940f78a884966adb8cc63bf91b675331c99a (patch) | |
| tree | e1f9f314834b3eca87bb067c1aa26c0f4f9580ef /gcc/fold-const.c | |
| parent | 56863927e3a3bf4518f50a28cb9fa5b4a09fbbf1 (diff) | |
| download | gcc-17e3940f78a884966adb8cc63bf91b675331c99a.tar.gz | |
* fold-const.c (extract_muldiv) [case PLUS_EXPR]: If not MULT_EXPR,
check if either operand is divisible by C.
(multiple_of_p): Handle LSHIFT_EXPR with small constant shift.
If type is signed, consider negative numbers as well.
* gcc.c-torture/execute/20010222-1.c: New test.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@39996 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/fold-const.c')
| -rw-r--r-- | gcc/fold-const.c | 33 |
1 files changed, 29 insertions, 4 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 1793f555680..99a602cd297 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -4487,7 +4487,12 @@ extract_muldiv (t, c, code, wide_type) constant. */ t1 = extract_muldiv (op0, c, code, wide_type); t2 = extract_muldiv (op1, c, code, wide_type); - if (t1 != 0 && t2 != 0) + if (t1 != 0 && t2 != 0 + && (code == MULT_EXPR + /* If not multiplication, we can only do this if either operand + is divisible by c. */ + || multiple_of_p (ctype, op0, c) + || multiple_of_p (ctype, op1, c))) return fold (build (tcode, ctype, convert (ctype, t1), convert (ctype, t2))); @@ -7280,6 +7285,25 @@ multiple_of_p (type, top, bottom) return (multiple_of_p (type, TREE_OPERAND (top, 0), bottom) && multiple_of_p (type, TREE_OPERAND (top, 1), bottom)); + case LSHIFT_EXPR: + if (TREE_CODE (TREE_OPERAND (top, 1)) == INTEGER_CST) + { + tree op1, t1; + + op1 = TREE_OPERAND (top, 1); + /* const_binop may not detect overflow correctly, + so check for it explicitly here. */ + if (TYPE_PRECISION (TREE_TYPE (size_one_node)) + > TREE_INT_CST_LOW (op1) + && TREE_INT_CST_HIGH (op1) == 0 + && 0 != (t1 = convert (type, + const_binop (LSHIFT_EXPR, size_one_node, + op1, 0))) + && ! TREE_OVERFLOW (t1)) + return multiple_of_p (type, t1, bottom); + } + return 0; + case NOP_EXPR: /* Can't handle conversions from non-integral or wider integral type. */ if ((TREE_CODE (TREE_TYPE (TREE_OPERAND (top, 0))) != INTEGER_TYPE) @@ -7293,9 +7317,10 @@ multiple_of_p (type, top, bottom) return multiple_of_p (type, TREE_OPERAND (top, 0), bottom); case INTEGER_CST: - if ((TREE_CODE (bottom) != INTEGER_CST) - || (tree_int_cst_sgn (top) < 0) - || (tree_int_cst_sgn (bottom) < 0)) + if (TREE_CODE (bottom) != INTEGER_CST + || (TREE_UNSIGNED (type) + && (tree_int_cst_sgn (top) < 0 + || tree_int_cst_sgn (bottom) < 0))) return 0; return integer_zerop (const_binop (TRUNC_MOD_EXPR, top, bottom, 0)); |