Commit a4d034d7 by Jason Merrill Committed by Jason Merrill

Fix conversions for built-in operator overloading candidates.

While working on C++20 operator<=>, I noticed that build_new_op_1 was doing
too much conversion when a built-in candidate was selected; the standard
says it should only perform user-defined conversions, and then leave the
normal operator semantics to handle any standard conversions.  This is
important for operator<=> because a comparison of two different unscoped
enums is ill-formed; if we promote the enums to int here, cp_build_binary_op
never gets to see the original operand types, so we can't give the error.

	* call.c (build_new_op_1): Don't apply any standard conversions to
	the operands of a built-in operator.  Don't suppress conversions in
	cp_build_unary_op.
	* typeck.c (cp_build_unary_op): Do integral promotions for enums.

From-SVN: r275744
parent c4438114
2019-09-15 Jason Merrill <jason@redhat.com>
* call.c (build_new_op_1): Don't apply any standard conversions to
the operands of a built-in operator. Don't suppress conversions in
cp_build_unary_op.
* typeck.c (cp_build_unary_op): Do integral promotions for enums.
2019-09-15 Marek Polacek <polacek@redhat.com> 2019-09-15 Marek Polacek <polacek@redhat.com>
PR c++/91740 - ICE with constexpr call and ?: in ARRAY_REF. PR c++/91740 - ICE with constexpr call and ?: in ARRAY_REF.
......
...@@ -6139,41 +6139,40 @@ build_new_op_1 (const op_location_t &loc, enum tree_code code, int flags, ...@@ -6139,41 +6139,40 @@ build_new_op_1 (const op_location_t &loc, enum tree_code code, int flags,
break; break;
} }
/* We need to strip any leading REF_BIND so that bitfields /* "If a built-in candidate is selected by overload resolution, the
don't cause errors. This should not remove any important operands of class type are converted to the types of the
conversions, because builtins don't apply to class corresponding parameters of the selected operation function,
objects directly. */ except that the second standard conversion sequence of a
user-defined conversion sequence (12.3.3.1.2) is not applied." */
conv = cand->convs[0]; conv = cand->convs[0];
if (conv->kind == ck_ref_bind) if (conv->user_conv_p)
conv = next_conversion (conv); {
arg1 = convert_like (conv, arg1, complain); while (conv->kind != ck_user)
conv = next_conversion (conv);
arg1 = convert_like (conv, arg1, complain);
}
if (arg2) if (arg2)
{ {
conv = cand->convs[1]; conv = cand->convs[1];
if (conv->kind == ck_ref_bind) if (conv->user_conv_p)
conv = next_conversion (conv); {
else while (conv->kind != ck_user)
arg2 = decay_conversion (arg2, complain); conv = next_conversion (conv);
arg2 = convert_like (conv, arg2, complain);
/* We need to call warn_logical_operator before }
converting arg2 to a boolean_type, but after
decaying an enumerator to its value. */
if (complain & tf_warning)
warn_logical_operator (loc, code, boolean_type_node,
code_orig_arg1, arg1,
code_orig_arg2, arg2);
arg2 = convert_like (conv, arg2, complain);
} }
if (arg3) if (arg3)
{ {
conv = cand->convs[2]; conv = cand->convs[2];
if (conv->kind == ck_ref_bind) if (conv->user_conv_p)
conv = next_conversion (conv); {
convert_like (conv, arg3, complain); while (conv->kind != ck_user)
conv = next_conversion (conv);
arg3 = convert_like (conv, arg3, complain);
}
} }
} }
} }
...@@ -6241,7 +6240,7 @@ build_new_op_1 (const op_location_t &loc, enum tree_code code, int flags, ...@@ -6241,7 +6240,7 @@ build_new_op_1 (const op_location_t &loc, enum tree_code code, int flags,
case REALPART_EXPR: case REALPART_EXPR:
case IMAGPART_EXPR: case IMAGPART_EXPR:
case ABS_EXPR: case ABS_EXPR:
return cp_build_unary_op (code, arg1, candidates != 0, complain); return cp_build_unary_op (code, arg1, false, complain);
case ARRAY_REF: case ARRAY_REF:
return cp_build_array_ref (input_location, arg1, arg2, complain); return cp_build_array_ref (input_location, arg1, arg2, complain);
......
...@@ -6242,7 +6242,7 @@ cp_build_unary_op (enum tree_code code, tree xarg, bool noconvert, ...@@ -6242,7 +6242,7 @@ cp_build_unary_op (enum tree_code code, tree xarg, bool noconvert,
: _("wrong type argument to unary plus")); : _("wrong type argument to unary plus"));
else else
{ {
if (!noconvert && CP_INTEGRAL_TYPE_P (TREE_TYPE (arg))) if (!noconvert && INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (arg)))
arg = cp_perform_integral_promotions (arg, complain); arg = cp_perform_integral_promotions (arg, complain);
/* Make sure the result is not an lvalue: a unary plus or minus /* Make sure the result is not an lvalue: a unary plus or minus
...@@ -6267,7 +6267,7 @@ cp_build_unary_op (enum tree_code code, tree xarg, bool noconvert, ...@@ -6267,7 +6267,7 @@ cp_build_unary_op (enum tree_code code, tree xarg, bool noconvert,
| WANT_VECTOR_OR_COMPLEX, | WANT_VECTOR_OR_COMPLEX,
arg, true))) arg, true)))
errstring = _("wrong type argument to bit-complement"); errstring = _("wrong type argument to bit-complement");
else if (!noconvert && CP_INTEGRAL_TYPE_P (TREE_TYPE (arg))) else if (!noconvert && INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (arg)))
{ {
/* Warn if the expression has boolean value. */ /* Warn if the expression has boolean value. */
if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE
......
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