diff options
Diffstat (limited to 'gcc/fold-const.c')
-rw-r--r-- | gcc/fold-const.c | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index ef95ae3d4a5..5a101f27451 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -13086,6 +13086,45 @@ fold (tree expr) switch (code) { + case ARRAY_REF: + { + tree op0 = TREE_OPERAND (t, 0); + tree op1 = TREE_OPERAND (t, 1); + + if (TREE_CODE (op1) == INTEGER_CST + && TREE_CODE (op0) == CONSTRUCTOR + && ! type_contains_placeholder_p (TREE_TYPE (op0))) + { + VEC(constructor_elt,gc) *elts = CONSTRUCTOR_ELTS (op0); + unsigned HOST_WIDE_INT end = VEC_length (constructor_elt, elts); + unsigned HOST_WIDE_INT begin = 0; + + /* Find a matching index by means of a binary search. */ + while (begin != end) + { + unsigned HOST_WIDE_INT middle = (begin + end) / 2; + tree index = VEC_index (constructor_elt, elts, middle)->index; + + if (TREE_CODE (index) == INTEGER_CST + && tree_int_cst_lt (index, op1)) + begin = middle + 1; + else if (TREE_CODE (index) == INTEGER_CST + && tree_int_cst_lt (op1, index)) + end = middle; + else if (TREE_CODE (index) == RANGE_EXPR + && tree_int_cst_lt (TREE_OPERAND (index, 1), op1)) + begin = middle + 1; + else if (TREE_CODE (index) == RANGE_EXPR + && tree_int_cst_lt (op1, TREE_OPERAND (index, 0))) + end = middle; + else + return VEC_index (constructor_elt, elts, middle)->value; + } + } + + return t; + } + case CONST_DECL: return fold (DECL_INITIAL (t)); |