Hi!
>From what I can see, this has been voted in as a DR and as it means
we warn less often than before in -std={gnu,c}++2{0,3} modes or with
-Wvolatile, I wonder if it shouldn't be backported to affected release
branches as well.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2022-08-15 Jakub Jelinek <ja...@redhat.com>
* typeck.cc (cp_build_modify_expr): Implement
P2327R1 - De-deprecating volatile compound operations. Don't warn
for |=, &= or ^= with volatile lhs.
* expr.cc (mark_use) <case MODIFY_EXPR>: Adjust warning wording,
leave out simple.
* g++.dg/cpp2a/volatile1.C: Adjust for de-deprecation of volatile
compound |=, &= and ^= operations.
* g++.dg/cpp2a/volatile3.C: Likewise.
* g++.dg/cpp2a/volatile5.C: Likewise.
--- gcc/cp/typeck.cc.jj 2022-06-17 17:36:19.689107831 +0200
+++ gcc/cp/typeck.cc 2022-08-14 11:14:15.368316963 +0200
@@ -9136,10 +9136,14 @@ cp_build_modify_expr (location_t loc, tr
/* An expression of the form E1 op= E2. [expr.ass] says:
"Such expressions are deprecated if E1 has volatile-qualified
- type." We warn here rather than in cp_genericize_r because
+ type and op is not one of the bitwise operators |, &, ^."
+ We warn here rather than in cp_genericize_r because
for compound assignments we are supposed to warn even if the
assignment is a discarded-value expression. */
- if (TREE_THIS_VOLATILE (lhs) || CP_TYPE_VOLATILE_P (lhstype))
+ if (modifycode != BIT_AND_EXPR
+ && modifycode != BIT_IOR_EXPR
+ && modifycode != BIT_XOR_EXPR
+ && (TREE_THIS_VOLATILE (lhs) || CP_TYPE_VOLATILE_P (lhstype)))
warning_at (loc, OPT_Wvolatile,
"compound assignment with %<volatile%>-qualified left "
"operand is deprecated");
--- gcc/cp/expr.cc.jj 2022-06-27 11:18:02.268063761 +0200
+++ gcc/cp/expr.cc 2022-08-14 11:41:37.555649422 +0200
@@ -220,7 +220,7 @@ mark_use (tree expr, bool rvalue_p, bool
case MODIFY_EXPR:
{
tree lhs = TREE_OPERAND (expr, 0);
- /* [expr.ass] "A simple assignment whose left operand is of
+ /* [expr.ass] "An assignment whose left operand is of
a volatile-qualified type is deprecated unless the assignment
is either a discarded-value expression or appears in an
unevaluated context." */
@@ -230,7 +230,7 @@ mark_use (tree expr, bool rvalue_p, bool
&& !TREE_THIS_VOLATILE (expr))
{
if (warning_at (location_of (expr), OPT_Wvolatile,
- "using value of simple assignment with "
+ "using value of assignment with "
"%<volatile%>-qualified left operand is "
"deprecated"))
/* Make sure not to warn about this assignment again. */
--- gcc/testsuite/g++.dg/cpp2a/volatile1.C.jj 2020-07-28 15:39:10.013756159
+0200
+++ gcc/testsuite/g++.dg/cpp2a/volatile1.C 2022-08-14 11:46:42.721626890
+0200
@@ -56,6 +56,9 @@ fn2 ()
vi = i;
vi = i = 42;
i = vi = 42; // { dg-warning "assignment with .volatile.-qualified left
operand is deprecated" "" { target c++20 } }
+ i = vi |= 42; // { dg-warning "using value of assignment with
.volatile.-qualified left operand is deprecated" "" { target c++20 } }
+ i = vi &= 42; // { dg-warning "using value of assignment with
.volatile.-qualified left operand is deprecated" "" { target c++20 } }
+ i = vi ^= 42; // { dg-warning "using value of assignment with
.volatile.-qualified left operand is deprecated" "" { target c++20 } }
&(vi = i); // { dg-warning "assignment with .volatile.-qualified left
operand is deprecated" "" { target c++20 } }
(vi = 42, 45);
(i = vi = 42, 10); // { dg-warning "assignment with .volatile.-qualified
left operand is deprecated" "" { target c++20 } }
@@ -74,8 +77,9 @@ fn2 ()
vi += i; // { dg-warning "assignment with .volatile.-qualified left operand
is deprecated" "" { target c++20 } }
vi -= i; // { dg-warning "assignment with .volatile.-qualified left operand
is deprecated" "" { target c++20 } }
vi %= i; // { dg-warning "assignment with .volatile.-qualified left operand
is deprecated" "" { target c++20 } }
- vi ^= i; // { dg-warning "assignment with .volatile.-qualified left operand
is deprecated" "" { target c++20 } }
- vi |= i; // { dg-warning "assignment with .volatile.-qualified left operand
is deprecated" "" { target c++20 } }
+ vi ^= i; // { dg-bogus "assignment with .volatile.-qualified left operand is
deprecated" }
+ vi |= i; // { dg-bogus "assignment with .volatile.-qualified left operand is
deprecated" }
+ vi &= i; // { dg-bogus "assignment with .volatile.-qualified left operand is
deprecated" }
vi /= i; // { dg-warning "assignment with .volatile.-qualified left operand
is deprecated" "" { target c++20 } }
vi = vi += 42; // { dg-warning "assignment with .volatile.-qualified left
operand is deprecated" "" { target c++20 } }
vi += vi = 42; // { dg-warning "assignment with .volatile.-qualified left
operand is deprecated" "" { target c++20 } }
@@ -131,7 +135,8 @@ void raccoon ()
volatile T t, u;
t = 42;
u = t = 42; // { dg-warning "assignment with .volatile.-qualified left
operand is deprecated" "" { target c++20 } }
- t &= 42; // { dg-warning "assignment with .volatile.-qualified left operand
is deprecated" "" { target c++20 } }
+ t += 42; // { dg-warning "assignment with .volatile.-qualified left operand
is deprecated" "" { target c++20 } }
+ t &= 42; // { dg-bogus "assignment with .volatile.-qualified left operand is
deprecated" }
}
void
--- gcc/testsuite/g++.dg/cpp2a/volatile3.C.jj 2020-01-12 11:54:37.149402305
+0100
+++ gcc/testsuite/g++.dg/cpp2a/volatile3.C 2022-08-14 11:47:05.691324132
+0200
@@ -57,6 +57,9 @@ fn2 ()
vi = i;
vi = i = 42;
i = vi = 42; // { dg-warning "assignment with .volatile.-qualified left
operand is deprecated" }
+ i = vi |= 42; // { dg-warning "using value of assignment with
.volatile.-qualified left operand is deprecated" }
+ i = vi &= 42; // { dg-warning "using value of assignment with
.volatile.-qualified left operand is deprecated" }
+ i = vi ^= 42; // { dg-warning "using value of assignment with
.volatile.-qualified left operand is deprecated" }
&(vi = i); // { dg-warning "assignment with .volatile.-qualified left
operand is deprecated" }
(vi = 42, 45);
(i = vi = 42, 10); // { dg-warning "assignment with .volatile.-qualified
left operand is deprecated" }
@@ -75,8 +78,9 @@ fn2 ()
vi += i; // { dg-warning "assignment with .volatile.-qualified left operand
is deprecated" }
vi -= i; // { dg-warning "assignment with .volatile.-qualified left operand
is deprecated" }
vi %= i; // { dg-warning "assignment with .volatile.-qualified left operand
is deprecated" }
- vi ^= i; // { dg-warning "assignment with .volatile.-qualified left operand
is deprecated" }
- vi |= i; // { dg-warning "assignment with .volatile.-qualified left operand
is deprecated" }
+ vi ^= i; // { dg-bogus "assignment with .volatile.-qualified left operand is
deprecated" }
+ vi |= i; // { dg-bogus "assignment with .volatile.-qualified left operand is
deprecated" }
+ vi &= i; // { dg-bogus "assignment with .volatile.-qualified left operand is
deprecated" }
vi /= i; // { dg-warning "assignment with .volatile.-qualified left operand
is deprecated" }
vi = vi += 42; // { dg-warning "assignment with .volatile.-qualified left
operand is deprecated" }
vi += vi = 42; // { dg-warning "assignment with .volatile.-qualified left
operand is deprecated" }
@@ -132,7 +136,8 @@ void raccoon ()
volatile T t, u;
t = 42;
u = t = 42; // { dg-warning "assignment with .volatile.-qualified left
operand is deprecated" }
- t &= 42; // { dg-warning "assignment with .volatile.-qualified left operand
is deprecated" }
+ t += 42; // { dg-warning "assignment with .volatile.-qualified left operand
is deprecated" }
+ t &= 42; // { dg-bogus "assignment with .volatile.-qualified left operand is
deprecated" }
}
void
--- gcc/testsuite/g++.dg/cpp2a/volatile5.C.jj 2021-02-08 19:07:33.110166905
+0100
+++ gcc/testsuite/g++.dg/cpp2a/volatile5.C 2022-08-14 11:42:47.779723765
+0200
@@ -8,8 +8,8 @@ f (bool b)
{
(b ? x : y) = 1;
(b ? x : y) += 1; // { dg-warning "compound assignment" "" { target c++20 } }
- z = (b ? x : y) = 1; // { dg-warning "using value of simple assignment" "" {
target c++20 } }
- ((z = 2) ? x : y) = 1; // { dg-warning "using value of simple assignment" ""
{ target c++20 } }
- (b ? (x = 2) : y) = 1; // { dg-warning "using value of simple assignment" ""
{ target c++20 } }
- (b ? x : (y = 5)) = 1; // { dg-warning "using value of simple assignment" ""
{ target c++20 } }
+ z = (b ? x : y) = 1; // { dg-warning "using value of assignment" "" { target
c++20 } }
+ ((z = 2) ? x : y) = 1; // { dg-warning "using value of assignment" "" {
target c++20 } }
+ (b ? (x = 2) : y) = 1; // { dg-warning "using value of assignment" "" {
target c++20 } }
+ (b ? x : (y = 5)) = 1; // { dg-warning "using value of assignment" "" {
target c++20 } }
}
Jakub
