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author | mpolacek <mpolacek@138bc75d-0d04-0410-961f-82ee72b054a4> | 2015-03-30 18:39:17 +0000 |
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committer | mpolacek <mpolacek@138bc75d-0d04-0410-961f-82ee72b054a4> | 2015-03-30 18:39:17 +0000 |
commit | 35b68da831ae24ef73c7daeeb9655b2f318c4752 (patch) | |
tree | 05c8ccb5585dce489c8e83023f76d83a742cb992 /gcc/cp/constexpr.c | |
parent | 8126264b8be7e05fb1ddbeb1df4f29be745f3412 (diff) | |
download | gcc-35b68da831ae24ef73c7daeeb9655b2f318c4752.tar.gz |
PR c++/65398
* constexpr.c (cxx_fold_indirect_ref): Don't perform the
*(&A[i] p+ j) => A[i + j] transformation here.
(cxx_eval_pointer_plus_expression): New function.
(cxx_eval_constant_expression): Use it here.
* g++.dg/cpp0x/pr65398-2.C: New test.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@221777 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/cp/constexpr.c')
-rw-r--r-- | gcc/cp/constexpr.c | 72 |
1 files changed, 51 insertions, 21 deletions
diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c index 2f094721546..2100f94cdd0 100644 --- a/gcc/cp/constexpr.c +++ b/gcc/cp/constexpr.c @@ -2427,27 +2427,6 @@ cxx_fold_indirect_ref (location_t loc, tree type, tree op0, bool *empty_base) break; } } - /* *(&A[i] p+ j) => A[i + j] */ - else if (TREE_CODE (op00) == ARRAY_REF - && TREE_CODE (TREE_OPERAND (op00, 1)) == INTEGER_CST - && TREE_CODE (op01) == INTEGER_CST) - { - tree t = fold_convert_loc (loc, ssizetype, - TREE_OPERAND (op00, 1)); - tree nelts - = array_type_nelts_top (TREE_TYPE (TREE_OPERAND (op00, 0))); - /* Don't fold an out-of-bound access. */ - if (!tree_int_cst_le (t, nelts)) - return NULL_TREE; - /* Make sure to treat the second operand of POINTER_PLUS_EXPR - as signed. */ - op01 = fold_build2_loc (loc, EXACT_DIV_EXPR, ssizetype, - cp_fold_convert (ssizetype, op01), - TYPE_SIZE_UNIT (type)); - t = size_binop_loc (loc, PLUS_EXPR, op01, t); - return build4_loc (loc, ARRAY_REF, type, TREE_OPERAND (op00, 0), - t, NULL_TREE, NULL_TREE); - } } } /* *(foo *)fooarrptr => (*fooarrptr)[0] */ @@ -2942,6 +2921,51 @@ cxx_eval_switch_expr (const constexpr_ctx *ctx, tree t, return NULL_TREE; } +/* Subroutine of cxx_eval_constant_expression. + Attempt to reduce a POINTER_PLUS_EXPR expression T. */ + +static tree +cxx_eval_pointer_plus_expression (const constexpr_ctx *ctx, tree t, + bool lval, bool *non_constant_p, + bool *overflow_p) +{ + tree op00 = TREE_OPERAND (t, 0); + tree op01 = TREE_OPERAND (t, 1); + location_t loc = EXPR_LOCATION (t); + + STRIP_NOPS (op00); + if (TREE_CODE (op00) != ADDR_EXPR) + return NULL_TREE; + + op00 = TREE_OPERAND (op00, 0); + + /* &A[i] p+ j => &A[i + j] */ + if (TREE_CODE (op00) == ARRAY_REF + && TREE_CODE (TREE_OPERAND (op00, 1)) == INTEGER_CST + && TREE_CODE (op01) == INTEGER_CST) + { + tree type = TREE_TYPE (op00); + t = fold_convert_loc (loc, ssizetype, TREE_OPERAND (op00, 1)); + tree nelts = array_type_nelts_top (TREE_TYPE (TREE_OPERAND (op00, 0))); + /* Don't fold an out-of-bound access. */ + if (!tree_int_cst_le (t, nelts)) + return NULL_TREE; + /* Make sure to treat the second operand of POINTER_PLUS_EXPR + as signed. */ + op01 = fold_build2_loc (loc, EXACT_DIV_EXPR, ssizetype, + cp_fold_convert (ssizetype, op01), + TYPE_SIZE_UNIT (type)); + t = size_binop_loc (loc, PLUS_EXPR, op01, t); + t = build4_loc (loc, ARRAY_REF, type, TREE_OPERAND (op00, 0), + t, NULL_TREE, NULL_TREE); + t = cp_build_addr_expr (t, tf_warning_or_error); + return cxx_eval_constant_expression (ctx, t, lval, non_constant_p, + overflow_p); + } + + return NULL_TREE; +} + /* Attempt to reduce the expression T to a constant value. On failure, issue diagnostic and return error_mark_node. */ /* FIXME unify with c_fully_fold */ @@ -3247,6 +3271,12 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, break; case POINTER_PLUS_EXPR: + r = cxx_eval_pointer_plus_expression (ctx, t, lval, non_constant_p, + overflow_p); + if (r) + break; + /* else fall through */ + case PLUS_EXPR: case MINUS_EXPR: case MULT_EXPR: |