Since r11-5188-g32934a4f45a721, we drop qualifiers during l-to-r
conversion by creating a NOP_EXPR. For e.g.
const int i = i;
that means that the DECL_INITIAL is '(int) i' and not 'i' anymore.
Consequently, we don't suppress_warning here:
711 case DECL_EXPR:
715 if (VAR_P (DECL_EXPR_DECL (*expr_p))
716 && !DECL_EXTERNAL (DECL_EXPR_DECL (*expr_p))
717 && !TREE_STATIC (DECL_EXPR_DECL (*expr_p))
718 && (DECL_INITIAL (DECL_EXPR_DECL (*expr_p)) == DECL_EXPR_DECL
(*expr_p))
719 && !warn_init_self)
720 suppress_warning (DECL_EXPR_DECL (*expr_p), OPT_Winit_self);
because of the check on line 718 -- (int) i is not i. So -Wno-init-self
doesn't disable the warning as it's supposed to.
The following patch fixes it...except it doesn't, for volatile variables
in C++. The problem is that for
volatile int k = k;
we see that the initializer has TREE_SIDE_EFFECTS, so we perform dynamic
initialization. So there's no DECL_INITIAL and the suppress_warning
call above is never done. I suppose we could amend get_no_uninit_warning
to return true for volatile-qualified expressions. I mean, can we ever
say for a fact that a volatile variable is uninitialized?
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
PR middle-end/102633
gcc/c-family/ChangeLog:
* c-gimplify.cc (c_gimplify_expr): Strip NOPs of DECL_INITIAL.
gcc/testsuite/ChangeLog:
* c-c++-common/Winit-self1.c: New test.
* c-c++-common/Winit-self2.c: New test.
---
gcc/c-family/c-gimplify.cc | 18 +++++++------
gcc/testsuite/c-c++-common/Winit-self1.c | 32 ++++++++++++++++++++++++
gcc/testsuite/c-c++-common/Winit-self2.c | 31 +++++++++++++++++++++++
3 files changed, 74 insertions(+), 7 deletions(-)
create mode 100644 gcc/testsuite/c-c++-common/Winit-self1.c
create mode 100644 gcc/testsuite/c-c++-common/Winit-self2.c
diff --git a/gcc/c-family/c-gimplify.cc b/gcc/c-family/c-gimplify.cc
index a6f26c9b0d3..2e011830846 100644
--- a/gcc/c-family/c-gimplify.cc
+++ b/gcc/c-family/c-gimplify.cc
@@ -712,13 +712,17 @@ c_gimplify_expr (tree *expr_p, gimple_seq *pre_p
ATTRIBUTE_UNUSED,
/* This is handled mostly by gimplify.cc, but we have to deal with
not warning about int x = x; as it is a GCC extension to turn off
this warning but only if warn_init_self is zero. */
- if (VAR_P (DECL_EXPR_DECL (*expr_p))
- && !DECL_EXTERNAL (DECL_EXPR_DECL (*expr_p))
- && !TREE_STATIC (DECL_EXPR_DECL (*expr_p))
- && (DECL_INITIAL (DECL_EXPR_DECL (*expr_p)) == DECL_EXPR_DECL
(*expr_p))
- && !warn_init_self)
- suppress_warning (DECL_EXPR_DECL (*expr_p), OPT_Winit_self);
- break;
+ {
+ tree &decl = DECL_EXPR_DECL (*expr_p);
+ if (VAR_P (decl)
+ && !DECL_EXTERNAL (decl)
+ && !TREE_STATIC (decl)
+ && (DECL_INITIAL (decl)
+ && tree_strip_nop_conversions (DECL_INITIAL (decl)) == decl)
+ && !warn_init_self)
+ suppress_warning (decl, OPT_Winit_self);
+ break;
+ }
case PREINCREMENT_EXPR:
case PREDECREMENT_EXPR:
diff --git a/gcc/testsuite/c-c++-common/Winit-self1.c
b/gcc/testsuite/c-c++-common/Winit-self1.c
new file mode 100644
index 00000000000..2a1a755fc71
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/Winit-self1.c
@@ -0,0 +1,32 @@
+/* PR middle-end/102633 */
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -Wno-init-self" } */
+
+int
+fn1 (void)
+{
+ int i = i;
+ return i;
+}
+
+int
+fn2 ()
+{
+ const int j = j;
+ return j;
+}
+
+int
+fn3 ()
+{
+ /* ??? Do we want this warning in C++? Probably not with -Wno-init-self. */
+ volatile int k = k; /* { dg-warning "used uninitialized" "" { target c++ } }
*/
+ return k;
+}
+
+int
+fn4 ()
+{
+ const volatile int l = l; /* { dg-warning "used uninitialized" "" { target
c++ } } */
+ return l;
+}
diff --git a/gcc/testsuite/c-c++-common/Winit-self2.c
b/gcc/testsuite/c-c++-common/Winit-self2.c
new file mode 100644
index 00000000000..13aa9efdf26
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/Winit-self2.c
@@ -0,0 +1,31 @@
+/* PR middle-end/102633 */
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -Winit-self" } */
+
+int
+fn1 (void)
+{
+ int i = i; /* { dg-warning "used uninitialized" } */
+ return i;
+}
+
+int
+fn2 ()
+{
+ const int j = j; /* { dg-warning "used uninitialized" } */
+ return j;
+}
+
+int
+fn3 ()
+{
+ volatile int k = k; /* { dg-warning "used uninitialized" } */
+ return k;
+}
+
+int
+fn4 ()
+{
+ const volatile int l = l; /* { dg-warning "used uninitialized" } */
+ return l;
+}
base-commit: 600956c81c784f4a0cc9d10f6e03e01847afd961
--
2.37.1
