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* [PATCH] c-family: Honor -Wno-init-self for cv-qual vars [PR102633]
@ 2022-07-26 19:03 Marek Polacek
  2022-07-26 20:24 ` Jason Merrill
  2022-07-27  6:41 ` [PATCH] " Richard Biener
  0 siblings, 2 replies; 9+ messages in thread
From: Marek Polacek @ 2022-07-26 19:03 UTC (permalink / raw)
  To: GCC Patches; +Cc: Jason Merrill, Joseph Myers, Richard Biener

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


^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH] c-family: Honor -Wno-init-self for cv-qual vars [PR102633]
  2022-07-26 19:03 [PATCH] c-family: Honor -Wno-init-self for cv-qual vars [PR102633] Marek Polacek
@ 2022-07-26 20:24 ` Jason Merrill
  2022-07-26 21:31   ` Marek Polacek
  2022-07-27  6:41 ` [PATCH] " Richard Biener
  1 sibling, 1 reply; 9+ messages in thread
From: Jason Merrill @ 2022-07-26 20:24 UTC (permalink / raw)
  To: Marek Polacek, GCC Patches; +Cc: Joseph Myers, Richard Biener

On 7/26/22 15:03, Marek Polacek wrote:
> 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.

I wonder if we want to handle this i = i case earlier, like in finish_decl.

> 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


^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH] c-family: Honor -Wno-init-self for cv-qual vars [PR102633]
  2022-07-26 20:24 ` Jason Merrill
@ 2022-07-26 21:31   ` Marek Polacek
  2022-08-06 22:29     ` Jason Merrill
  0 siblings, 1 reply; 9+ messages in thread
From: Marek Polacek @ 2022-07-26 21:31 UTC (permalink / raw)
  To: Jason Merrill; +Cc: GCC Patches, Joseph Myers, Richard Biener

On Tue, Jul 26, 2022 at 04:24:18PM -0400, Jason Merrill wrote:
> On 7/26/22 15:03, Marek Polacek wrote:
> > 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.
> 
> I wonder if we want to handle this i = i case earlier, like in finish_decl.

I could, something like

@@ -5381,7 +5381,14 @@ finish_decl (tree decl, location_t init_loc, tree init,
     init = NULL_TREE;

   if (init)
-    store_init_value (init_loc, decl, init, origtype);
+    {
+      /* In the self-init case, undo the artificial NOP_EXPR we may have
+    added in convert_lvalue_to_rvalue so that c_gimplify_expr/DECL_EXPR
+    can perform suppress_warning.  */
+      if (TREE_CODE (init) == NOP_EXPR && TREE_OPERAND (init, 0) == decl)
+   init = TREE_OPERAND (init, 0);
+      store_init_value (init_loc, decl, init, origtype);
+    }

but then I'd have to do the same thing in cp_finish_decl because
decay_conversion also adds a NOP_EXPR for cv-qualified non-class prvalues.
Is that what we want?  To me that seems less clean than having c_gimplify_expr
see through NOP_EXPRs.

Marek


^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH] c-family: Honor -Wno-init-self for cv-qual vars [PR102633]
  2022-07-26 19:03 [PATCH] c-family: Honor -Wno-init-self for cv-qual vars [PR102633] Marek Polacek
  2022-07-26 20:24 ` Jason Merrill
@ 2022-07-27  6:41 ` Richard Biener
  2022-07-27 11:37   ` Marek Polacek
  1 sibling, 1 reply; 9+ messages in thread
From: Richard Biener @ 2022-07-27  6:41 UTC (permalink / raw)
  To: Marek Polacek; +Cc: GCC Patches, Jason Merrill, Joseph Myers

On Tue, 26 Jul 2022, Marek Polacek wrote:

> 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?

As I said in the bug the bug is probably that we emit uninitialized
diagnostics for volatiles at all?  OTOH 'volatile' is recommended
for vars live around setjmp/longjmp and there diagnostics would be
welcome.  It's probably the difference between "compiler-hands-off"
and "hardware-controlled" :/

> 
> 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
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg,
Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman;
HRB 36809 (AG Nuernberg)

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH] c-family: Honor -Wno-init-self for cv-qual vars [PR102633]
  2022-07-27  6:41 ` [PATCH] " Richard Biener
@ 2022-07-27 11:37   ` Marek Polacek
  0 siblings, 0 replies; 9+ messages in thread
From: Marek Polacek @ 2022-07-27 11:37 UTC (permalink / raw)
  To: Richard Biener; +Cc: GCC Patches, Joseph Myers

On Wed, Jul 27, 2022 at 06:41:09AM +0000, Richard Biener via Gcc-patches wrote:
> On Tue, 26 Jul 2022, Marek Polacek wrote:
> 
> > 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?
> 
> As I said in the bug the bug is probably that we emit uninitialized
> diagnostics for volatiles at all?

Non-volatile const variables also have this problem, so I think we still
need this patch (or something like it).

> OTOH 'volatile' is recommended
> for vars live around setjmp/longjmp and there diagnostics would be
> welcome.  It's probably the difference between "compiler-hands-off"
> and "hardware-controlled" :/

Ah, you're right.  Then I guess it's better to leave the warning be,
(but we still have a discrepancy between C and C++).

Marek


^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH] c-family: Honor -Wno-init-self for cv-qual vars [PR102633]
  2022-07-26 21:31   ` Marek Polacek
@ 2022-08-06 22:29     ` Jason Merrill
  2022-08-08 19:06       ` [PATCH v2] " Marek Polacek
  0 siblings, 1 reply; 9+ messages in thread
From: Jason Merrill @ 2022-08-06 22:29 UTC (permalink / raw)
  To: Marek Polacek; +Cc: GCC Patches, Joseph Myers, Richard Biener

On 7/26/22 14:31, Marek Polacek wrote:
> On Tue, Jul 26, 2022 at 04:24:18PM -0400, Jason Merrill wrote:
>> On 7/26/22 15:03, Marek Polacek wrote:
>>> 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.
>>
>> I wonder if we want to handle this i = i case earlier, like in finish_decl.
> 
> I could, something like
> 
> @@ -5381,7 +5381,14 @@ finish_decl (tree decl, location_t init_loc, tree init,
>       init = NULL_TREE;
> 
>     if (init)
> -    store_init_value (init_loc, decl, init, origtype);
> +    {
> +      /* In the self-init case, undo the artificial NOP_EXPR we may have
> +    added in convert_lvalue_to_rvalue so that c_gimplify_expr/DECL_EXPR
> +    can perform suppress_warning.  */
> +      if (TREE_CODE (init) == NOP_EXPR && TREE_OPERAND (init, 0) == decl)
> +   init = TREE_OPERAND (init, 0);
> +      store_init_value (init_loc, decl, init, origtype);
> +    }
> 
> but then I'd have to do the same thing in cp_finish_decl because
> decay_conversion also adds a NOP_EXPR for cv-qualified non-class prvalues.
> Is that what we want?  To me that seems less clean than having c_gimplify_expr
> see through NOP_EXPRs.

I was thinking of checking the form of the initializer before 
decay_conversion or anything else messes with it, and calling 
suppress_warning at that point instead of in c_gimplify_expr.

Jason


^ permalink raw reply	[flat|nested] 9+ messages in thread

* [PATCH v2] c-family: Honor -Wno-init-self for cv-qual vars [PR102633]
  2022-08-06 22:29     ` Jason Merrill
@ 2022-08-08 19:06       ` Marek Polacek
  2022-08-11  2:05         ` Jason Merrill
  2022-08-11 22:30         ` Jason Merrill
  0 siblings, 2 replies; 9+ messages in thread
From: Marek Polacek @ 2022-08-08 19:06 UTC (permalink / raw)
  To: Jason Merrill; +Cc: GCC Patches, Joseph Myers, Richard Biener

On Sat, Aug 06, 2022 at 03:29:05PM -0700, Jason Merrill wrote:
> On 7/26/22 14:31, Marek Polacek wrote:
> > On Tue, Jul 26, 2022 at 04:24:18PM -0400, Jason Merrill wrote:
> > > On 7/26/22 15:03, Marek Polacek wrote:
> > > > 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.
> > > 
> > > I wonder if we want to handle this i = i case earlier, like in finish_decl.
> > 
> > I could, something like
> > 
> > @@ -5381,7 +5381,14 @@ finish_decl (tree decl, location_t init_loc, tree init,
> >       init = NULL_TREE;
> > 
> >     if (init)
> > -    store_init_value (init_loc, decl, init, origtype);
> > +    {
> > +      /* In the self-init case, undo the artificial NOP_EXPR we may have
> > +    added in convert_lvalue_to_rvalue so that c_gimplify_expr/DECL_EXPR
> > +    can perform suppress_warning.  */
> > +      if (TREE_CODE (init) == NOP_EXPR && TREE_OPERAND (init, 0) == decl)
> > +   init = TREE_OPERAND (init, 0);
> > +      store_init_value (init_loc, decl, init, origtype);
> > +    }
> > 
> > but then I'd have to do the same thing in cp_finish_decl because
> > decay_conversion also adds a NOP_EXPR for cv-qualified non-class prvalues.
> > Is that what we want?  To me that seems less clean than having c_gimplify_expr
> > see through NOP_EXPRs.
> 
> I was thinking of checking the form of the initializer before
> decay_conversion or anything else messes with it, and calling
> suppress_warning at that point instead of in c_gimplify_expr.

Aaah, okay.  Here's a patch that does it.  In the C FE it has to
happen really early.  Now both front ends behave the same wrt volatiles!

Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?

-- >8 --
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 by moving the suppress_warning call from
c_gimplify_expr to the front ends, at points where we haven't created
the NOP_EXPR yet.

	PR middle-end/102633

gcc/c-family/ChangeLog:

	* c-gimplify.cc (c_gimplify_expr) <case DECL_EXPR>: Don't call
	suppress_warning here.

gcc/c/ChangeLog:

	* c-parser.cc (c_parser_initializer): Add new tree parameter.  Use it.
	Call suppress_warning.
	(c_parser_declaration_or_fndef): Pass d down to c_parser_initializer.
	(c_parser_omp_declare_reduction): Pass omp_priv down to
	c_parser_initializer.

gcc/cp/ChangeLog:

	* decl.cc (cp_finish_decl): Call suppress_warning.

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               | 12 ---------
 gcc/c/c-parser.cc                        | 19 ++++++++++++---
 gcc/cp/decl.cc                           |  8 ++++++
 gcc/testsuite/c-c++-common/Winit-self1.c | 31 ++++++++++++++++++++++++
 gcc/testsuite/c-c++-common/Winit-self2.c | 31 ++++++++++++++++++++++++
 5 files changed, 85 insertions(+), 16 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..039a4b93230 100644
--- a/gcc/c-family/c-gimplify.cc
+++ b/gcc/c-family/c-gimplify.cc
@@ -708,18 +708,6 @@ c_gimplify_expr (tree *expr_p, gimple_seq *pre_p ATTRIBUTE_UNUSED,
 	break;
       }
 
-    case DECL_EXPR:
-      /* 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;
-
     case PREINCREMENT_EXPR:
     case PREDECREMENT_EXPR:
     case POSTINCREMENT_EXPR:
diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc
index 92049d1a101..6ed17ed9c48 100644
--- a/gcc/c/c-parser.cc
+++ b/gcc/c/c-parser.cc
@@ -1521,7 +1521,7 @@ static struct c_arg_info *c_parser_parms_list_declarator (c_parser *, tree,
 static struct c_parm *c_parser_parameter_declaration (c_parser *, tree, bool);
 static tree c_parser_simple_asm_expr (c_parser *);
 static tree c_parser_gnu_attributes (c_parser *);
-static struct c_expr c_parser_initializer (c_parser *);
+static struct c_expr c_parser_initializer (c_parser *, tree);
 static struct c_expr c_parser_braced_init (c_parser *, tree, bool,
 					   struct obstack *);
 static void c_parser_initelt (c_parser *, struct obstack *);
@@ -2286,7 +2286,7 @@ c_parser_declaration_or_fndef (c_parser *parser, bool fndef_ok,
 		  int flag_sanitize_save = flag_sanitize;
 		  if (TREE_CODE (d) == PARM_DECL)
 		    flag_sanitize = 0;
-		  init = c_parser_initializer (parser);
+		  init = c_parser_initializer (parser, d);
 		  flag_sanitize = flag_sanitize_save;
 		  finish_init ();
 		}
@@ -5211,11 +5211,13 @@ c_parser_type_name (c_parser *parser, bool alignas_ok)
    Any expression without commas is accepted in the syntax for the
    constant-expressions, with non-constant expressions rejected later.
 
+   DECL is the declaration we're parsing this initializer for.
+
    This function is only used for top-level initializers; for nested
    ones, see c_parser_initval.  */
 
 static struct c_expr
-c_parser_initializer (c_parser *parser)
+c_parser_initializer (c_parser *parser, tree decl)
 {
   if (c_parser_next_token_is (parser, CPP_OPEN_BRACE))
     return c_parser_braced_init (parser, NULL_TREE, false, NULL);
@@ -5224,6 +5226,15 @@ c_parser_initializer (c_parser *parser)
       struct c_expr ret;
       location_t loc = c_parser_peek_token (parser)->location;
       ret = c_parser_expr_no_commas (parser, NULL);
+      /* 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)
+	  && !DECL_EXTERNAL (decl)
+	  && !TREE_STATIC (decl)
+	  && ret.value == decl
+	  && !warn_init_self)
+	suppress_warning (decl, OPT_Winit_self);
       if (TREE_CODE (ret.value) != STRING_CST
 	  && TREE_CODE (ret.value) != COMPOUND_LITERAL_EXPR)
 	ret = convert_lvalue_to_rvalue (loc, ret, true, true);
@@ -22576,7 +22587,7 @@ c_parser_omp_declare_reduction (c_parser *parser, enum pragma_context context)
 		  location_t loc = c_parser_peek_token (parser)->location;
 		  rich_location richloc (line_table, loc);
 		  start_init (omp_priv, NULL_TREE, 0, &richloc);
-		  struct c_expr init = c_parser_initializer (parser);
+		  struct c_expr init = c_parser_initializer (parser, omp_priv);
 		  finish_init ();
 		  finish_decl (omp_priv, loc, init.value,
 		      	       init.original_type, NULL_TREE);
diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index 70ad681467e..ff56fddba54 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -8253,6 +8253,14 @@ cp_finish_decl (tree decl, tree init, bool init_const_expr_p,
 	      && !TYPE_REF_P (type))
 	    TREE_CONSTANT (decl) = 1;
 	}
+      /* 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 (!DECL_EXTERNAL (decl)
+	  && !TREE_STATIC (decl)
+	  && decl == tree_strip_any_location_wrapper (init)
+	  && !warn_init_self)
+	suppress_warning (decl, OPT_Winit_self);
     }
 
   if (flag_openmp
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..740b83b5e9f
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/Winit-self1.c
@@ -0,0 +1,31 @@
+/* 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 ()
+{
+  volatile int k = k;
+  return k;
+}
+
+int
+fn4 ()
+{
+  const volatile int l = l;
+  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: 21c7aab09805d0c8c7695c8a69c8715d673a739a
-- 
2.37.1


^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH v2] c-family: Honor -Wno-init-self for cv-qual vars [PR102633]
  2022-08-08 19:06       ` [PATCH v2] " Marek Polacek
@ 2022-08-11  2:05         ` Jason Merrill
  2022-08-11 22:30         ` Jason Merrill
  1 sibling, 0 replies; 9+ messages in thread
From: Jason Merrill @ 2022-08-11  2:05 UTC (permalink / raw)
  To: Marek Polacek; +Cc: GCC Patches, Joseph Myers, Richard Biener

On 8/8/22 12:06, Marek Polacek wrote:
> On Sat, Aug 06, 2022 at 03:29:05PM -0700, Jason Merrill wrote:
>> On 7/26/22 14:31, Marek Polacek wrote:
>>> On Tue, Jul 26, 2022 at 04:24:18PM -0400, Jason Merrill wrote:
>>>> On 7/26/22 15:03, Marek Polacek wrote:
>>>>> 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.
>>>>
>>>> I wonder if we want to handle this i = i case earlier, like in finish_decl.
>>>
>>> I could, something like
>>>
>>> @@ -5381,7 +5381,14 @@ finish_decl (tree decl, location_t init_loc, tree init,
>>>        init = NULL_TREE;
>>>
>>>      if (init)
>>> -    store_init_value (init_loc, decl, init, origtype);
>>> +    {
>>> +      /* In the self-init case, undo the artificial NOP_EXPR we may have
>>> +    added in convert_lvalue_to_rvalue so that c_gimplify_expr/DECL_EXPR
>>> +    can perform suppress_warning.  */
>>> +      if (TREE_CODE (init) == NOP_EXPR && TREE_OPERAND (init, 0) == decl)
>>> +   init = TREE_OPERAND (init, 0);
>>> +      store_init_value (init_loc, decl, init, origtype);
>>> +    }
>>>
>>> but then I'd have to do the same thing in cp_finish_decl because
>>> decay_conversion also adds a NOP_EXPR for cv-qualified non-class prvalues.
>>> Is that what we want?  To me that seems less clean than having c_gimplify_expr
>>> see through NOP_EXPRs.
>>
>> I was thinking of checking the form of the initializer before
>> decay_conversion or anything else messes with it, and calling
>> suppress_warning at that point instead of in c_gimplify_expr.
> 
> Aaah, okay.  Here's a patch that does it.  In the C FE it has to
> happen really early.  Now both front ends behave the same wrt volatiles!
> 
> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?

LGTM.

> -- >8 --
> 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 by moving the suppress_warning call from
> c_gimplify_expr to the front ends, at points where we haven't created
> the NOP_EXPR yet.
> 
> 	PR middle-end/102633
> 
> gcc/c-family/ChangeLog:
> 
> 	* c-gimplify.cc (c_gimplify_expr) <case DECL_EXPR>: Don't call
> 	suppress_warning here.
> 
> gcc/c/ChangeLog:
> 
> 	* c-parser.cc (c_parser_initializer): Add new tree parameter.  Use it.
> 	Call suppress_warning.
> 	(c_parser_declaration_or_fndef): Pass d down to c_parser_initializer.
> 	(c_parser_omp_declare_reduction): Pass omp_priv down to
> 	c_parser_initializer.
> 
> gcc/cp/ChangeLog:
> 
> 	* decl.cc (cp_finish_decl): Call suppress_warning.
> 
> 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               | 12 ---------
>   gcc/c/c-parser.cc                        | 19 ++++++++++++---
>   gcc/cp/decl.cc                           |  8 ++++++
>   gcc/testsuite/c-c++-common/Winit-self1.c | 31 ++++++++++++++++++++++++
>   gcc/testsuite/c-c++-common/Winit-self2.c | 31 ++++++++++++++++++++++++
>   5 files changed, 85 insertions(+), 16 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..039a4b93230 100644
> --- a/gcc/c-family/c-gimplify.cc
> +++ b/gcc/c-family/c-gimplify.cc
> @@ -708,18 +708,6 @@ c_gimplify_expr (tree *expr_p, gimple_seq *pre_p ATTRIBUTE_UNUSED,
>   	break;
>         }
>   
> -    case DECL_EXPR:
> -      /* 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;
> -
>       case PREINCREMENT_EXPR:
>       case PREDECREMENT_EXPR:
>       case POSTINCREMENT_EXPR:
> diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc
> index 92049d1a101..6ed17ed9c48 100644
> --- a/gcc/c/c-parser.cc
> +++ b/gcc/c/c-parser.cc
> @@ -1521,7 +1521,7 @@ static struct c_arg_info *c_parser_parms_list_declarator (c_parser *, tree,
>   static struct c_parm *c_parser_parameter_declaration (c_parser *, tree, bool);
>   static tree c_parser_simple_asm_expr (c_parser *);
>   static tree c_parser_gnu_attributes (c_parser *);
> -static struct c_expr c_parser_initializer (c_parser *);
> +static struct c_expr c_parser_initializer (c_parser *, tree);
>   static struct c_expr c_parser_braced_init (c_parser *, tree, bool,
>   					   struct obstack *);
>   static void c_parser_initelt (c_parser *, struct obstack *);
> @@ -2286,7 +2286,7 @@ c_parser_declaration_or_fndef (c_parser *parser, bool fndef_ok,
>   		  int flag_sanitize_save = flag_sanitize;
>   		  if (TREE_CODE (d) == PARM_DECL)
>   		    flag_sanitize = 0;
> -		  init = c_parser_initializer (parser);
> +		  init = c_parser_initializer (parser, d);
>   		  flag_sanitize = flag_sanitize_save;
>   		  finish_init ();
>   		}
> @@ -5211,11 +5211,13 @@ c_parser_type_name (c_parser *parser, bool alignas_ok)
>      Any expression without commas is accepted in the syntax for the
>      constant-expressions, with non-constant expressions rejected later.
>   
> +   DECL is the declaration we're parsing this initializer for.
> +
>      This function is only used for top-level initializers; for nested
>      ones, see c_parser_initval.  */
>   
>   static struct c_expr
> -c_parser_initializer (c_parser *parser)
> +c_parser_initializer (c_parser *parser, tree decl)
>   {
>     if (c_parser_next_token_is (parser, CPP_OPEN_BRACE))
>       return c_parser_braced_init (parser, NULL_TREE, false, NULL);
> @@ -5224,6 +5226,15 @@ c_parser_initializer (c_parser *parser)
>         struct c_expr ret;
>         location_t loc = c_parser_peek_token (parser)->location;
>         ret = c_parser_expr_no_commas (parser, NULL);
> +      /* 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)
> +	  && !DECL_EXTERNAL (decl)
> +	  && !TREE_STATIC (decl)
> +	  && ret.value == decl
> +	  && !warn_init_self)
> +	suppress_warning (decl, OPT_Winit_self);
>         if (TREE_CODE (ret.value) != STRING_CST
>   	  && TREE_CODE (ret.value) != COMPOUND_LITERAL_EXPR)
>   	ret = convert_lvalue_to_rvalue (loc, ret, true, true);
> @@ -22576,7 +22587,7 @@ c_parser_omp_declare_reduction (c_parser *parser, enum pragma_context context)
>   		  location_t loc = c_parser_peek_token (parser)->location;
>   		  rich_location richloc (line_table, loc);
>   		  start_init (omp_priv, NULL_TREE, 0, &richloc);
> -		  struct c_expr init = c_parser_initializer (parser);
> +		  struct c_expr init = c_parser_initializer (parser, omp_priv);
>   		  finish_init ();
>   		  finish_decl (omp_priv, loc, init.value,
>   		      	       init.original_type, NULL_TREE);
> diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
> index 70ad681467e..ff56fddba54 100644
> --- a/gcc/cp/decl.cc
> +++ b/gcc/cp/decl.cc
> @@ -8253,6 +8253,14 @@ cp_finish_decl (tree decl, tree init, bool init_const_expr_p,
>   	      && !TYPE_REF_P (type))
>   	    TREE_CONSTANT (decl) = 1;
>   	}
> +      /* 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 (!DECL_EXTERNAL (decl)
> +	  && !TREE_STATIC (decl)
> +	  && decl == tree_strip_any_location_wrapper (init)
> +	  && !warn_init_self)
> +	suppress_warning (decl, OPT_Winit_self);
>       }
>   
>     if (flag_openmp
> 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..740b83b5e9f
> --- /dev/null
> +++ b/gcc/testsuite/c-c++-common/Winit-self1.c
> @@ -0,0 +1,31 @@
> +/* 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 ()
> +{
> +  volatile int k = k;
> +  return k;
> +}
> +
> +int
> +fn4 ()
> +{
> +  const volatile int l = l;
> +  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: 21c7aab09805d0c8c7695c8a69c8715d673a739a


^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH v2] c-family: Honor -Wno-init-self for cv-qual vars [PR102633]
  2022-08-08 19:06       ` [PATCH v2] " Marek Polacek
  2022-08-11  2:05         ` Jason Merrill
@ 2022-08-11 22:30         ` Jason Merrill
  1 sibling, 0 replies; 9+ messages in thread
From: Jason Merrill @ 2022-08-11 22:30 UTC (permalink / raw)
  To: Marek Polacek; +Cc: GCC Patches, Joseph Myers, Richard Biener

On 8/8/22 12:06, Marek Polacek wrote:
> On Sat, Aug 06, 2022 at 03:29:05PM -0700, Jason Merrill wrote:
>> On 7/26/22 14:31, Marek Polacek wrote:
>>> On Tue, Jul 26, 2022 at 04:24:18PM -0400, Jason Merrill wrote:
>>>> On 7/26/22 15:03, Marek Polacek wrote:
>>>>> 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.
>>>>
>>>> I wonder if we want to handle this i = i case earlier, like in finish_decl.
>>>
>>> I could, something like
>>>
>>> @@ -5381,7 +5381,14 @@ finish_decl (tree decl, location_t init_loc, tree init,
>>>        init = NULL_TREE;
>>>
>>>      if (init)
>>> -    store_init_value (init_loc, decl, init, origtype);
>>> +    {
>>> +      /* In the self-init case, undo the artificial NOP_EXPR we may have
>>> +    added in convert_lvalue_to_rvalue so that c_gimplify_expr/DECL_EXPR
>>> +    can perform suppress_warning.  */
>>> +      if (TREE_CODE (init) == NOP_EXPR && TREE_OPERAND (init, 0) == decl)
>>> +   init = TREE_OPERAND (init, 0);
>>> +      store_init_value (init_loc, decl, init, origtype);
>>> +    }
>>>
>>> but then I'd have to do the same thing in cp_finish_decl because
>>> decay_conversion also adds a NOP_EXPR for cv-qualified non-class prvalues.
>>> Is that what we want?  To me that seems less clean than having c_gimplify_expr
>>> see through NOP_EXPRs.
>>
>> I was thinking of checking the form of the initializer before
>> decay_conversion or anything else messes with it, and calling
>> suppress_warning at that point instead of in c_gimplify_expr.
> 
> Aaah, okay.  Here's a patch that does it.  In the C FE it has to
> happen really early.  Now both front ends behave the same wrt volatiles!
> 
> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?

LGTM.

> -- >8 --
> 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 by moving the suppress_warning call from
> c_gimplify_expr to the front ends, at points where we haven't created
> the NOP_EXPR yet.
> 
> 	PR middle-end/102633
> 
> gcc/c-family/ChangeLog:
> 
> 	* c-gimplify.cc (c_gimplify_expr) <case DECL_EXPR>: Don't call
> 	suppress_warning here.
> 
> gcc/c/ChangeLog:
> 
> 	* c-parser.cc (c_parser_initializer): Add new tree parameter.  Use it.
> 	Call suppress_warning.
> 	(c_parser_declaration_or_fndef): Pass d down to c_parser_initializer.
> 	(c_parser_omp_declare_reduction): Pass omp_priv down to
> 	c_parser_initializer.
> 
> gcc/cp/ChangeLog:
> 
> 	* decl.cc (cp_finish_decl): Call suppress_warning.
> 
> 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               | 12 ---------
>   gcc/c/c-parser.cc                        | 19 ++++++++++++---
>   gcc/cp/decl.cc                           |  8 ++++++
>   gcc/testsuite/c-c++-common/Winit-self1.c | 31 ++++++++++++++++++++++++
>   gcc/testsuite/c-c++-common/Winit-self2.c | 31 ++++++++++++++++++++++++
>   5 files changed, 85 insertions(+), 16 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..039a4b93230 100644
> --- a/gcc/c-family/c-gimplify.cc
> +++ b/gcc/c-family/c-gimplify.cc
> @@ -708,18 +708,6 @@ c_gimplify_expr (tree *expr_p, gimple_seq *pre_p ATTRIBUTE_UNUSED,
>   	break;
>         }
>   
> -    case DECL_EXPR:
> -      /* 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;
> -
>       case PREINCREMENT_EXPR:
>       case PREDECREMENT_EXPR:
>       case POSTINCREMENT_EXPR:
> diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc
> index 92049d1a101..6ed17ed9c48 100644
> --- a/gcc/c/c-parser.cc
> +++ b/gcc/c/c-parser.cc
> @@ -1521,7 +1521,7 @@ static struct c_arg_info *c_parser_parms_list_declarator (c_parser *, tree,
>   static struct c_parm *c_parser_parameter_declaration (c_parser *, tree, bool);
>   static tree c_parser_simple_asm_expr (c_parser *);
>   static tree c_parser_gnu_attributes (c_parser *);
> -static struct c_expr c_parser_initializer (c_parser *);
> +static struct c_expr c_parser_initializer (c_parser *, tree);
>   static struct c_expr c_parser_braced_init (c_parser *, tree, bool,
>   					   struct obstack *);
>   static void c_parser_initelt (c_parser *, struct obstack *);
> @@ -2286,7 +2286,7 @@ c_parser_declaration_or_fndef (c_parser *parser, bool fndef_ok,
>   		  int flag_sanitize_save = flag_sanitize;
>   		  if (TREE_CODE (d) == PARM_DECL)
>   		    flag_sanitize = 0;
> -		  init = c_parser_initializer (parser);
> +		  init = c_parser_initializer (parser, d);
>   		  flag_sanitize = flag_sanitize_save;
>   		  finish_init ();
>   		}
> @@ -5211,11 +5211,13 @@ c_parser_type_name (c_parser *parser, bool alignas_ok)
>      Any expression without commas is accepted in the syntax for the
>      constant-expressions, with non-constant expressions rejected later.
>   
> +   DECL is the declaration we're parsing this initializer for.
> +
>      This function is only used for top-level initializers; for nested
>      ones, see c_parser_initval.  */
>   
>   static struct c_expr
> -c_parser_initializer (c_parser *parser)
> +c_parser_initializer (c_parser *parser, tree decl)
>   {
>     if (c_parser_next_token_is (parser, CPP_OPEN_BRACE))
>       return c_parser_braced_init (parser, NULL_TREE, false, NULL);
> @@ -5224,6 +5226,15 @@ c_parser_initializer (c_parser *parser)
>         struct c_expr ret;
>         location_t loc = c_parser_peek_token (parser)->location;
>         ret = c_parser_expr_no_commas (parser, NULL);
> +      /* 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)
> +	  && !DECL_EXTERNAL (decl)
> +	  && !TREE_STATIC (decl)
> +	  && ret.value == decl
> +	  && !warn_init_self)
> +	suppress_warning (decl, OPT_Winit_self);
>         if (TREE_CODE (ret.value) != STRING_CST
>   	  && TREE_CODE (ret.value) != COMPOUND_LITERAL_EXPR)
>   	ret = convert_lvalue_to_rvalue (loc, ret, true, true);
> @@ -22576,7 +22587,7 @@ c_parser_omp_declare_reduction (c_parser *parser, enum pragma_context context)
>   		  location_t loc = c_parser_peek_token (parser)->location;
>   		  rich_location richloc (line_table, loc);
>   		  start_init (omp_priv, NULL_TREE, 0, &richloc);
> -		  struct c_expr init = c_parser_initializer (parser);
> +		  struct c_expr init = c_parser_initializer (parser, omp_priv);
>   		  finish_init ();
>   		  finish_decl (omp_priv, loc, init.value,
>   		      	       init.original_type, NULL_TREE);
> diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
> index 70ad681467e..ff56fddba54 100644
> --- a/gcc/cp/decl.cc
> +++ b/gcc/cp/decl.cc
> @@ -8253,6 +8253,14 @@ cp_finish_decl (tree decl, tree init, bool init_const_expr_p,
>   	      && !TYPE_REF_P (type))
>   	    TREE_CONSTANT (decl) = 1;
>   	}
> +      /* 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 (!DECL_EXTERNAL (decl)
> +	  && !TREE_STATIC (decl)
> +	  && decl == tree_strip_any_location_wrapper (init)
> +	  && !warn_init_self)
> +	suppress_warning (decl, OPT_Winit_self);
>       }
>   
>     if (flag_openmp
> 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..740b83b5e9f
> --- /dev/null
> +++ b/gcc/testsuite/c-c++-common/Winit-self1.c
> @@ -0,0 +1,31 @@
> +/* 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 ()
> +{
> +  volatile int k = k;
> +  return k;
> +}
> +
> +int
> +fn4 ()
> +{
> +  const volatile int l = l;
> +  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: 21c7aab09805d0c8c7695c8a69c8715d673a739a


^ permalink raw reply	[flat|nested] 9+ messages in thread

end of thread, other threads:[~2022-08-11 22:31 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-07-26 19:03 [PATCH] c-family: Honor -Wno-init-self for cv-qual vars [PR102633] Marek Polacek
2022-07-26 20:24 ` Jason Merrill
2022-07-26 21:31   ` Marek Polacek
2022-08-06 22:29     ` Jason Merrill
2022-08-08 19:06       ` [PATCH v2] " Marek Polacek
2022-08-11  2:05         ` Jason Merrill
2022-08-11 22:30         ` Jason Merrill
2022-07-27  6:41 ` [PATCH] " Richard Biener
2022-07-27 11:37   ` Marek Polacek

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