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.
Tested x86_64-pc-linux-gnu, applying to trunk.
* 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.
---
gcc/cp/call.c | 51 ++++++++++++++++++++++++------------------------
gcc/cp/typeck.c | 4 ++--
gcc/cp/ChangeLog | 7 +++++++
3 files changed, 34 insertions(+), 28 deletions(-)
diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index c3045d948c5..457fa6605c2 100644
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -6139,41 +6139,40 @@ build_new_op_1 (const op_location_t &loc, enum
tree_code code, int flags,
break;
}
- /* We need to strip any leading REF_BIND so that bitfields
- don't cause errors. This should not remove any important
- conversions, because builtins don't apply to class
- objects directly. */
+ /* "If a built-in candidate is selected by overload resolution, the
+ operands of class type are converted to the types of the
+ corresponding parameters of the selected operation function,
+ 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];
- if (conv->kind == ck_ref_bind)
- conv = next_conversion (conv);
- arg1 = convert_like (conv, arg1, complain);
+ if (conv->user_conv_p)
+ {
+ while (conv->kind != ck_user)
+ conv = next_conversion (conv);
+ arg1 = convert_like (conv, arg1, complain);
+ }
if (arg2)
{
conv = cand->convs[1];
- if (conv->kind == ck_ref_bind)
- conv = next_conversion (conv);
- else
- arg2 = decay_conversion (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 (conv->user_conv_p)
+ {
+ while (conv->kind != ck_user)
+ conv = next_conversion (conv);
+ arg2 = convert_like (conv, arg2, complain);
+ }
}
+
if (arg3)
{
conv = cand->convs[2];
- if (conv->kind == ck_ref_bind)
- conv = next_conversion (conv);
- convert_like (conv, arg3, complain);
+ if (conv->user_conv_p)
+ {
+ 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,
case REALPART_EXPR:
case IMAGPART_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:
return cp_build_array_ref (input_location, arg1, arg2, complain);
diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index 70094d1b426..620f2c9afdf 100644
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -6242,7 +6242,7 @@ cp_build_unary_op (enum tree_code code, tree xarg, bool
noconvert,
: _("wrong type argument to unary plus"));
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);
/* 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,
| WANT_VECTOR_OR_COMPLEX,
arg, true)))
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. */
if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index e92d49f1b76..a03a428109b 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,10 @@
+2019-09-15 Jason Merrill <ja...@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 <pola...@redhat.com>
PR c++/91740 - ICE with constexpr call and ?: in ARRAY_REF.
--
2.21.0
