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Diffstat (limited to 'gcc/tree-ssa-dom.c')
| -rw-r--r-- | gcc/tree-ssa-dom.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/gcc/tree-ssa-dom.c b/gcc/tree-ssa-dom.c index 211bfcf5cc4..6a6f027e90c 100644 --- a/gcc/tree-ssa-dom.c +++ b/gcc/tree-ssa-dom.c @@ -536,6 +536,29 @@ hashable_expr_equal_p (const struct hashable_expr *expr0, } } +/* Generate a hash value for a pair of expressions. This can be used + iteratively by passing a previous result as the VAL argument. + + The same hash value is always returned for a given pair of expressions, + regardless of the order in which they are presented. This is useful in + hashing the operands of commutative functions. */ + +static hashval_t +iterative_hash_exprs_commutative (const_tree t1, + const_tree t2, hashval_t val) +{ + hashval_t one = iterative_hash_expr (t1, 0); + hashval_t two = iterative_hash_expr (t2, 0); + hashval_t t; + + if (one > two) + t = one, one = two, two = t; + val = iterative_hash_hashval_t (one, val); + val = iterative_hash_hashval_t (two, val); + + return val; +} + /* Compute a hash value for a hashable_expr value EXPR and a previously accumulated hash value VAL. If two hashable_expr values compare equal with hashable_expr_equal_p, they must |