On Wed, Mar 21, 2018 at 01:01:38PM -0400, Jason Merrill wrote:
> >> Hmm, it would be nice to share this with the similar patterns in
> >> unary_complex_lvalue and cp_build_modify_expr.
>
> > You mean just outline the
> > if (TREE_SIDE_EFFECTS (TREE_OPERAND (lhs, 0)))
> > lhs = build2 (TREE_CODE (lhs), TREE_TYPE (lhs),
> > cp_stabilize_reference (TREE_OPERAND (lhs, 0)),
> > TREE_OPERAND (lhs, 1));
> > lhs = build2 (COMPOUND_EXPR, lhstype, lhs, TREE_OPERAND (lhs, 0));
> > into lhs = some_function (lhs); and use that in finish_asm_stmt,
> > unary_complex_lvalue and cp_build_modify_expr in these spots?
>
> > I really have no idea how to commonize anything else, e.g. the COMPOUND_EXPR
> > handling is substantially different between the 3 functions.
>
> > Any suggestion for the some_function name if you want that?
>
> Sure, that's something. How about genericize_compound_lvalue?
So like this (if it passes bootstrap/regtest)?
2018-03-21 Jakub Jelinek <ja...@redhat.com>
PR c++/84961
* cp-tree.h (genericize_compound_lvalue): Declare.
* typeck.c (genericize_compound_lvalue): New function.
(unary_complex_lvalue, cp_build_modify_expr): Use it.
* semantics.c (finish_asm_stmt): Replace MODIFY_EXPR, PREINCREMENT_EXPR
and PREDECREMENT_EXPR in output and "m" constrained input operands with
COMPOUND_EXPR. Call cxx_mark_addressable on the rightmost
COMPOUND_EXPR operand.
* c-c++-common/pr43690.c: Don't expect errors on "m" (--x) and
"m" (++x) in C++.
* g++.dg/torture/pr84961-1.C: New test.
* g++.dg/torture/pr84961-2.C: New test.
--- gcc/cp/cp-tree.h.jj 2018-03-20 22:05:57.053431471 +0100
+++ gcc/cp/cp-tree.h 2018-03-21 18:41:42.301838677 +0100
@@ -7145,6 +7145,7 @@ extern tree cp_build_addressof (locati
extern tree cp_build_addr_expr (tree, tsubst_flags_t);
extern tree cp_build_unary_op (enum tree_code, tree, bool,
tsubst_flags_t);
+extern tree genericize_compound_lvalue (tree);
extern tree unary_complex_lvalue (enum tree_code, tree);
extern tree build_x_conditional_expr (location_t, tree, tree, tree,
tsubst_flags_t);
--- gcc/cp/typeck.c.jj 2018-03-06 08:01:37.827883402 +0100
+++ gcc/cp/typeck.c 2018-03-21 18:40:23.350862956 +0100
@@ -6357,6 +6357,25 @@ build_unary_op (location_t /*location*/,
return cp_build_unary_op (code, xarg, noconvert, tf_warning_or_error);
}
+/* Adjust LVALUE, an MODIFY_EXPR, PREINCREMENT_EXPR or PREDECREMENT_EXPR,
+ so that it is a valid lvalue even for GENERIC by replacing
+ (lhs = rhs) with ((lhs = rhs), lhs)
+ (--lhs) with ((--lhs), lhs)
+ (++lhs) with ((++lhs), lhs)
+ and if lhs has side-effects, calling cp_stabilize_reference on it, so
+ that it can be evaluated multiple times. */
+
+tree
+genericize_compound_lvalue (tree lvalue)
+{
+ if (TREE_SIDE_EFFECTS (TREE_OPERAND (lvalue, 0)))
+ lvalue = build2 (TREE_CODE (lvalue), TREE_TYPE (lvalue),
+ cp_stabilize_reference (TREE_OPERAND (lvalue, 0)),
+ TREE_OPERAND (lvalue, 1));
+ return build2 (COMPOUND_EXPR, TREE_TYPE (TREE_OPERAND (lvalue, 0)),
+ lvalue, TREE_OPERAND (lvalue, 0));
+}
+
/* Apply unary lvalue-demanding operator CODE to the expression ARG
for certain kinds of expressions which are not really lvalues
but which we can accept as lvalues.
@@ -6391,17 +6410,7 @@ unary_complex_lvalue (enum tree_code cod
if (TREE_CODE (arg) == MODIFY_EXPR
|| TREE_CODE (arg) == PREINCREMENT_EXPR
|| TREE_CODE (arg) == PREDECREMENT_EXPR)
- {
- tree lvalue = TREE_OPERAND (arg, 0);
- if (TREE_SIDE_EFFECTS (lvalue))
- {
- lvalue = cp_stabilize_reference (lvalue);
- arg = build2 (TREE_CODE (arg), TREE_TYPE (arg),
- lvalue, TREE_OPERAND (arg, 1));
- }
- return unary_complex_lvalue
- (code, build2 (COMPOUND_EXPR, TREE_TYPE (lvalue), arg, lvalue));
- }
+ return unary_complex_lvalue (code, genericize_compound_lvalue (arg));
if (code != ADDR_EXPR)
return NULL_TREE;
@@ -7887,11 +7896,7 @@ cp_build_modify_expr (location_t loc, tr
case PREINCREMENT_EXPR:
if (compound_side_effects_p)
newrhs = rhs = stabilize_expr (rhs, &preeval);
- if (TREE_SIDE_EFFECTS (TREE_OPERAND (lhs, 0)))
- lhs = build2 (TREE_CODE (lhs), TREE_TYPE (lhs),
- cp_stabilize_reference (TREE_OPERAND (lhs, 0)),
- TREE_OPERAND (lhs, 1));
- lhs = build2 (COMPOUND_EXPR, lhstype, lhs, TREE_OPERAND (lhs, 0));
+ lhs = genericize_compound_lvalue (lhs);
maybe_add_compound:
/* If we had (bar, --foo) = 5; or (bar, (baz, --foo)) = 5;
and looked through the COMPOUND_EXPRs, readd them now around
@@ -7914,11 +7919,7 @@ cp_build_modify_expr (location_t loc, tr
case MODIFY_EXPR:
if (compound_side_effects_p)
newrhs = rhs = stabilize_expr (rhs, &preeval);
- if (TREE_SIDE_EFFECTS (TREE_OPERAND (lhs, 0)))
- lhs = build2 (TREE_CODE (lhs), TREE_TYPE (lhs),
- cp_stabilize_reference (TREE_OPERAND (lhs, 0)),
- TREE_OPERAND (lhs, 1));
- lhs = build2 (COMPOUND_EXPR, lhstype, lhs, TREE_OPERAND (lhs, 0));
+ lhs = genericize_compound_lvalue (lhs);
goto maybe_add_compound;
case MIN_EXPR:
--- gcc/cp/semantics.c.jj 2018-03-20 22:05:54.385430766 +0100
+++ gcc/cp/semantics.c 2018-03-21 18:42:50.084817830 +0100
@@ -1512,6 +1512,21 @@ finish_asm_stmt (int volatile_p, tree st
&& C_TYPE_FIELDS_READONLY (TREE_TYPE (operand)))))
cxx_readonly_error (operand, lv_asm);
+ tree *op = &operand;
+ while (TREE_CODE (*op) == COMPOUND_EXPR)
+ op = &TREE_OPERAND (*op, 1);
+ switch (TREE_CODE (*op))
+ {
+ case PREINCREMENT_EXPR:
+ case PREDECREMENT_EXPR:
+ case MODIFY_EXPR:
+ *op = genericize_compound_lvalue (*op);
+ op = &TREE_OPERAND (*op, 1);
+ break;
+ default:
+ break;
+ }
+
constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
oconstraints[i] = constraint;
@@ -1520,7 +1535,7 @@ finish_asm_stmt (int volatile_p, tree st
{
/* If the operand is going to end up in memory,
mark it addressable. */
- if (!allows_reg && !cxx_mark_addressable (operand))
+ if (!allows_reg && !cxx_mark_addressable (*op))
operand = error_mark_node;
}
else
@@ -1562,7 +1577,23 @@ finish_asm_stmt (int volatile_p, tree st
/* Strip the nops as we allow this case. FIXME, this really
should be rejected or made deprecated. */
STRIP_NOPS (operand);
- if (!cxx_mark_addressable (operand))
+
+ tree *op = &operand;
+ while (TREE_CODE (*op) == COMPOUND_EXPR)
+ op = &TREE_OPERAND (*op, 1);
+ switch (TREE_CODE (*op))
+ {
+ case PREINCREMENT_EXPR:
+ case PREDECREMENT_EXPR:
+ case MODIFY_EXPR:
+ *op = genericize_compound_lvalue (*op);
+ op = &TREE_OPERAND (*op, 1);
+ break;
+ default:
+ break;
+ }
+
+ if (!cxx_mark_addressable (*op))
operand = error_mark_node;
}
else if (!allows_reg && !allows_mem)
--- gcc/testsuite/c-c++-common/pr43690.c.jj 2018-03-20 22:05:54.237430727
+0100
+++ gcc/testsuite/c-c++-common/pr43690.c 2018-03-21 18:26:40.348908281
+0100
@@ -6,8 +6,8 @@ void
foo (char *x)
{
asm ("" : : "m" (x++)); /* { dg-error "is not directly addressable" } */
- asm ("" : : "m" (++x)); /* { dg-error "is not directly addressable" } */
+ asm ("" : : "m" (++x)); /* { dg-error "is not directly addressable" ""
{ target c } } */
asm ("" : : "m" (x--)); /* { dg-error "is not directly addressable" } */
- asm ("" : : "m" (--x)); /* { dg-error "is not directly addressable" } */
+ asm ("" : : "m" (--x)); /* { dg-error "is not directly addressable" ""
{ target c } } */
asm ("" : : "m" (x + 1)); /* { dg-error "is not directly addressable" } */
}
--- gcc/testsuite/g++.dg/torture/pr84961-1.C.jj 2018-03-21 18:26:40.349908281
+0100
+++ gcc/testsuite/g++.dg/torture/pr84961-1.C 2018-03-21 18:26:40.349908281
+0100
@@ -0,0 +1,24 @@
+// PR c++/84961
+// { dg-do compile }
+
+short a;
+volatile int b;
+int c, d;
+
+void
+foo ()
+{
+ asm volatile ("" : "=r" (b = a));
+}
+
+void
+bar ()
+{
+ asm volatile ("" : "=r" (++c, ++d, b = a));
+}
+
+void
+baz ()
+{
+ asm volatile ("" : "=r" (--b));
+}
--- gcc/testsuite/g++.dg/torture/pr84961-2.C.jj 2018-03-21 18:26:40.349908281
+0100
+++ gcc/testsuite/g++.dg/torture/pr84961-2.C 2018-03-21 18:26:40.349908281
+0100
@@ -0,0 +1,24 @@
+// PR c++/84961
+// { dg-do compile }
+
+short a;
+volatile int b;
+int c, d;
+
+void
+foo ()
+{
+ asm volatile ("" : : "m" (b = a));
+}
+
+void
+bar ()
+{
+ asm volatile ("" : : "m" (++c, ++d, b = a));
+}
+
+void
+baz ()
+{
+ asm volatile ("" : : "m" (--b));
+}
Jakub
