On 03/17/2016 03:16 PM, Martin Sebor wrote:
gcc-67376.patch
PR c++/67376 - [5/6 regression] Comparison with pointer to past-the-end
of array fails inside constant expression
PR c++/70170 - [6 regression] bogus not a constant expression error comparing
pointer to array to null
PR c++/70172 - incorrect reinterpret_cast from integer to pointer error
on invalid constexpr initialization
PR c++/60760 - arithmetic on null pointers should not be allowed in constant
expressions
PR c++/70228 - insufficient detail in diagnostics for a constexpr out of bounds
array subscript
gcc/testsuite/ChangeLog:
2016-03-17 Martin Sebor<mse...@redhat.com>
PR c++/67376
PR c++/70170
PR c++/70172
PR c++/60760
PR c++/70228
* g++.dg/cpp0x/constexpr-array-ptr10.C: New test.
* g++.dg/cpp0x/constexpr-array-ptr9.C: New test.
* g++.dg/cpp0x/constexpr-array5.C: Adjust text of expected diagnostic.
* g++.dg/cpp0x/constexpr-nullptr.C: Add test cases.
* g++.dg/cpp0x/constexpr-string.C: Same.
* g++.dg/cpp0x/constexpr-wstring2.C: Same.
* g++.dg/cpp0x/pr65398.C: Same.
* g++.dg/ext/constexpr-vla1.C: Same.
* g++.dg/ext/constexpr-vla2.C: Same.
* g++.dg/ext/constexpr-vla3.C: Same.
* g++.dg/ubsan/pr63956.C: Same.
gcc/cp/ChangeLog:
2016-03-17 Martin Sebor<mse...@redhat.com>
PR c++/67376
PR c++/70170
PR c++/70172
PR c++/60760
PR c++/70228
* constexpr.c (cxx_eval_binary_expression): Add argument.
(cxx_eval_component_reference): Same.
(cxx_eval_constant_expression): Same.
(cxx_eval_indirect_ref): Same.
(cxx_eval_outermost_constant_expr): Same.
(diag_array_subscript): New function.
(cxx_eval_call_expression): Adjust.
(cxx_eval_conditional_expression): Same.
(cxx_eval_array_reference): Detect null pointers.
(cxx_eval_statement_list): Adjust.
gcc/ChangeLog:
2016-03-17 Martin Sebor<mse...@redhat.com>
PR c++/67376
* fold-const.c (maybe_nonzero_address): New function.
(fold_comparison): Call it. Fold equality and relational
expressions involving null pointers.
(tree_single_nonzero_warnv_p): Call maybe_nonzero_address.
Index: gcc/cp/constexpr.c
===================================================================
--- gcc/cp/constexpr.c (revision 234306)
+++ gcc/cp/constexpr.c (working copy)
@@ -1839,11 +1874,26 @@ cxx_eval_array_reference (const constexp
@@ -3300,10 +3357,21 @@ cxx_eval_constant_expression (const cons
+
+ if (TREE_CODE (t) == INTEGER_CST
+ && TREE_CODE (TREE_TYPE (t)) == POINTER_TYPE
+ && !integer_zerop (t))
+ {
+ if (!ctx->quiet)
+ error ("null pointer arithmetic in %qE", t);
+ if (nullptr_p)
+ *nullptr_p = true;
+ }
Something looks odd here.
You're testing !integer_zerop, so in T is going to be non-NULL, but you
mentioned null pointer arithmetic in the error message. Am I missing
something here?
@@ -3738,15 +3812,32 @@ cxx_eval_constant_expression (const cons
Index: gcc/fold-const.c
@@ -8639,6 +8653,38 @@ fold_comparison (location_t loc, enum tr
base1 = build_fold_addr_expr_loc (loc, base1);
return fold_build2_loc (loc, code, type, base0, base1);
}
+
+ /* Comparison between an ordinary (non-weak) symbol and a null
+ pointer can be eliminated since such sybols must have a non
+ null address. */
+ else if (DECL_P (base0)
+ && maybe_nonzero_address (base0) > 0
+ // && (!HAS_DECL_ASSEMBLER_NAME_P (base0) || !DECL_WEAK (base0))
Please remove the commented out line.
+ /* Avoid folding references to struct members at offset 0 to
+ prevent tests like '&ptr->firstmember == 0' from getting
+ eliminated. When ptr is null, although the -> expression
+ is strictly speaking invalid, GCC retains it as a matter
+ of QoI. See PR c/44555. */
+ && (TREE_CODE (op0) != ADDR_EXPR
+ || TREE_CODE (TREE_OPERAND (op0, 0)) != COMPONENT_REF
+ || compare_tree_int (DECL_FIELD_OFFSET ((TREE_OPERAND
+ (TREE_OPERAND (op0, 0), 1))), 0))
+ && TREE_CODE (arg1) == INTEGER_CST
+ && compare_tree_int (arg1, 0) == 0)
+ {
+ switch (code)
+ {
+ case GE_EXPR:
+ case EQ_EXPR:
+ case LE_EXPR:
+ return boolean_false_node;
+ case GT_EXPR:
+ case LT_EXPR:
+ case NE_EXPR:
+ return boolean_true_node;
+ default: gcc_unreachable ();
Can you put the gcc_unreachable on a new line? I know there's a few
cases in the sources where it's on the default: line, but the vast
majority have it on its own line.
