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* [PATCH] c++: fix SIGFPE with -Wclass-memaccess [PR105634]
@ 2022-05-17 23:57 Marek Polacek
  2022-05-18 14:24 ` Jason Merrill
  0 siblings, 1 reply; 2+ messages in thread
From: Marek Polacek @ 2022-05-17 23:57 UTC (permalink / raw)
  To: Jason Merrill, GCC Patches

Here we crash because we attempt to % by 0.  Thus fixed.
While at it, I've moved the -Wclass-memaccess tests into warn/.
I've checked that the # of expected passes is the same before/after
the move.

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

	PR c++/105634

gcc/cp/ChangeLog:

	* call.cc (maybe_warn_class_memaccess): Avoid % by zero.

gcc/testsuite/ChangeLog:

	* g++.dg/Wclass-memaccess-2.C: Moved to...
	* g++.dg/warn/Wclass-memaccess-2.C: ...here.
	* g++.dg/Wclass-memaccess-3.C: Moved to...
	* g++.dg/warn/Wclass-memaccess-3.C: ...here.
	* g++.dg/Wclass-memaccess-4.C: Moved to...
	* g++.dg/warn/Wclass-memaccess-4.C: ...here.
	* g++.dg/Wclass-memaccess-5.C: Moved to...
	* g++.dg/warn/Wclass-memaccess-5.C: ...here.
	* g++.dg/Wclass-memaccess-6.C: Moved to...
	* g++.dg/warn/Wclass-memaccess-6.C: ...here.
	* g++.dg/Wclass-memaccess.C: Moved to...
	* g++.dg/warn/Wclass-memaccess.C: ...here.
	* g++.dg/warn/Wclass-memaccess-7.C: New test.
---
 gcc/cp/call.cc                                      |  2 ++
 .../g++.dg/{ => warn}/Wclass-memaccess-2.C          |  0
 .../g++.dg/{ => warn}/Wclass-memaccess-3.C          |  0
 .../g++.dg/{ => warn}/Wclass-memaccess-4.C          |  0
 .../g++.dg/{ => warn}/Wclass-memaccess-5.C          |  0
 .../g++.dg/{ => warn}/Wclass-memaccess-6.C          |  0
 gcc/testsuite/g++.dg/warn/Wclass-memaccess-7.C      | 13 +++++++++++++
 gcc/testsuite/g++.dg/{ => warn}/Wclass-memaccess.C  |  0
 8 files changed, 15 insertions(+)
 rename gcc/testsuite/g++.dg/{ => warn}/Wclass-memaccess-2.C (100%)
 rename gcc/testsuite/g++.dg/{ => warn}/Wclass-memaccess-3.C (100%)
 rename gcc/testsuite/g++.dg/{ => warn}/Wclass-memaccess-4.C (100%)
 rename gcc/testsuite/g++.dg/{ => warn}/Wclass-memaccess-5.C (100%)
 rename gcc/testsuite/g++.dg/{ => warn}/Wclass-memaccess-6.C (100%)
 create mode 100644 gcc/testsuite/g++.dg/warn/Wclass-memaccess-7.C
 rename gcc/testsuite/g++.dg/{ => warn}/Wclass-memaccess.C (100%)

diff --git a/gcc/cp/call.cc b/gcc/cp/call.cc
index 0240e364324..14c6037729f 100644
--- a/gcc/cp/call.cc
+++ b/gcc/cp/call.cc
@@ -10329,6 +10329,8 @@ maybe_warn_class_memaccess (location_t loc, tree fndecl,
 	  /* Finally, warn on partial copies.  */
 	  unsigned HOST_WIDE_INT typesize
 	    = tree_to_uhwi (TYPE_SIZE_UNIT (desttype));
+	  if (typesize == 0)
+	    break;
 	  if (unsigned HOST_WIDE_INT partial = tree_to_uhwi (sz) % typesize)
 	    warned = warning_at (loc, OPT_Wclass_memaccess,
 				 (typesize - partial > 1
diff --git a/gcc/testsuite/g++.dg/Wclass-memaccess-2.C b/gcc/testsuite/g++.dg/warn/Wclass-memaccess-2.C
similarity index 100%
rename from gcc/testsuite/g++.dg/Wclass-memaccess-2.C
rename to gcc/testsuite/g++.dg/warn/Wclass-memaccess-2.C
diff --git a/gcc/testsuite/g++.dg/Wclass-memaccess-3.C b/gcc/testsuite/g++.dg/warn/Wclass-memaccess-3.C
similarity index 100%
rename from gcc/testsuite/g++.dg/Wclass-memaccess-3.C
rename to gcc/testsuite/g++.dg/warn/Wclass-memaccess-3.C
diff --git a/gcc/testsuite/g++.dg/Wclass-memaccess-4.C b/gcc/testsuite/g++.dg/warn/Wclass-memaccess-4.C
similarity index 100%
rename from gcc/testsuite/g++.dg/Wclass-memaccess-4.C
rename to gcc/testsuite/g++.dg/warn/Wclass-memaccess-4.C
diff --git a/gcc/testsuite/g++.dg/Wclass-memaccess-5.C b/gcc/testsuite/g++.dg/warn/Wclass-memaccess-5.C
similarity index 100%
rename from gcc/testsuite/g++.dg/Wclass-memaccess-5.C
rename to gcc/testsuite/g++.dg/warn/Wclass-memaccess-5.C
diff --git a/gcc/testsuite/g++.dg/Wclass-memaccess-6.C b/gcc/testsuite/g++.dg/warn/Wclass-memaccess-6.C
similarity index 100%
rename from gcc/testsuite/g++.dg/Wclass-memaccess-6.C
rename to gcc/testsuite/g++.dg/warn/Wclass-memaccess-6.C
diff --git a/gcc/testsuite/g++.dg/warn/Wclass-memaccess-7.C b/gcc/testsuite/g++.dg/warn/Wclass-memaccess-7.C
new file mode 100644
index 00000000000..7e86b248629
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wclass-memaccess-7.C
@@ -0,0 +1,13 @@
+// PR c++/105634
+// { dg-do compile { target { c++11 } } }
+// { dg-options "-Wall" }
+
+struct s
+{
+  struct {} a[] = 1.0; // { dg-error "" }
+  void f (char *c)
+  {
+    s s;
+    __builtin_memcpy (&s, c, sizeof(s));
+  }
+};
diff --git a/gcc/testsuite/g++.dg/Wclass-memaccess.C b/gcc/testsuite/g++.dg/warn/Wclass-memaccess.C
similarity index 100%
rename from gcc/testsuite/g++.dg/Wclass-memaccess.C
rename to gcc/testsuite/g++.dg/warn/Wclass-memaccess.C

base-commit: c9852156dd2fedec130f6d8eb669579ef6237946
-- 
2.36.1


^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH] c++: fix SIGFPE with -Wclass-memaccess [PR105634]
  2022-05-17 23:57 [PATCH] c++: fix SIGFPE with -Wclass-memaccess [PR105634] Marek Polacek
@ 2022-05-18 14:24 ` Jason Merrill
  0 siblings, 0 replies; 2+ messages in thread
From: Jason Merrill @ 2022-05-18 14:24 UTC (permalink / raw)
  To: Marek Polacek, GCC Patches

On 5/17/22 19:57, Marek Polacek wrote:
> Here we crash because we attempt to % by 0.  Thus fixed.
> While at it, I've moved the -Wclass-memaccess tests into warn/.
> I've checked that the # of expected passes is the same before/after
> the move.
> 
> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?

OK.

> 	PR c++/105634
> 
> gcc/cp/ChangeLog:
> 
> 	* call.cc (maybe_warn_class_memaccess): Avoid % by zero.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* g++.dg/Wclass-memaccess-2.C: Moved to...
> 	* g++.dg/warn/Wclass-memaccess-2.C: ...here.
> 	* g++.dg/Wclass-memaccess-3.C: Moved to...
> 	* g++.dg/warn/Wclass-memaccess-3.C: ...here.
> 	* g++.dg/Wclass-memaccess-4.C: Moved to...
> 	* g++.dg/warn/Wclass-memaccess-4.C: ...here.
> 	* g++.dg/Wclass-memaccess-5.C: Moved to...
> 	* g++.dg/warn/Wclass-memaccess-5.C: ...here.
> 	* g++.dg/Wclass-memaccess-6.C: Moved to...
> 	* g++.dg/warn/Wclass-memaccess-6.C: ...here.
> 	* g++.dg/Wclass-memaccess.C: Moved to...
> 	* g++.dg/warn/Wclass-memaccess.C: ...here.
> 	* g++.dg/warn/Wclass-memaccess-7.C: New test.
> ---
>   gcc/cp/call.cc                                      |  2 ++
>   .../g++.dg/{ => warn}/Wclass-memaccess-2.C          |  0
>   .../g++.dg/{ => warn}/Wclass-memaccess-3.C          |  0
>   .../g++.dg/{ => warn}/Wclass-memaccess-4.C          |  0
>   .../g++.dg/{ => warn}/Wclass-memaccess-5.C          |  0
>   .../g++.dg/{ => warn}/Wclass-memaccess-6.C          |  0
>   gcc/testsuite/g++.dg/warn/Wclass-memaccess-7.C      | 13 +++++++++++++
>   gcc/testsuite/g++.dg/{ => warn}/Wclass-memaccess.C  |  0
>   8 files changed, 15 insertions(+)
>   rename gcc/testsuite/g++.dg/{ => warn}/Wclass-memaccess-2.C (100%)
>   rename gcc/testsuite/g++.dg/{ => warn}/Wclass-memaccess-3.C (100%)
>   rename gcc/testsuite/g++.dg/{ => warn}/Wclass-memaccess-4.C (100%)
>   rename gcc/testsuite/g++.dg/{ => warn}/Wclass-memaccess-5.C (100%)
>   rename gcc/testsuite/g++.dg/{ => warn}/Wclass-memaccess-6.C (100%)
>   create mode 100644 gcc/testsuite/g++.dg/warn/Wclass-memaccess-7.C
>   rename gcc/testsuite/g++.dg/{ => warn}/Wclass-memaccess.C (100%)
> 
> diff --git a/gcc/cp/call.cc b/gcc/cp/call.cc
> index 0240e364324..14c6037729f 100644
> --- a/gcc/cp/call.cc
> +++ b/gcc/cp/call.cc
> @@ -10329,6 +10329,8 @@ maybe_warn_class_memaccess (location_t loc, tree fndecl,
>   	  /* Finally, warn on partial copies.  */
>   	  unsigned HOST_WIDE_INT typesize
>   	    = tree_to_uhwi (TYPE_SIZE_UNIT (desttype));
> +	  if (typesize == 0)
> +	    break;
>   	  if (unsigned HOST_WIDE_INT partial = tree_to_uhwi (sz) % typesize)
>   	    warned = warning_at (loc, OPT_Wclass_memaccess,
>   				 (typesize - partial > 1
> diff --git a/gcc/testsuite/g++.dg/Wclass-memaccess-2.C b/gcc/testsuite/g++.dg/warn/Wclass-memaccess-2.C
> similarity index 100%
> rename from gcc/testsuite/g++.dg/Wclass-memaccess-2.C
> rename to gcc/testsuite/g++.dg/warn/Wclass-memaccess-2.C
> diff --git a/gcc/testsuite/g++.dg/Wclass-memaccess-3.C b/gcc/testsuite/g++.dg/warn/Wclass-memaccess-3.C
> similarity index 100%
> rename from gcc/testsuite/g++.dg/Wclass-memaccess-3.C
> rename to gcc/testsuite/g++.dg/warn/Wclass-memaccess-3.C
> diff --git a/gcc/testsuite/g++.dg/Wclass-memaccess-4.C b/gcc/testsuite/g++.dg/warn/Wclass-memaccess-4.C
> similarity index 100%
> rename from gcc/testsuite/g++.dg/Wclass-memaccess-4.C
> rename to gcc/testsuite/g++.dg/warn/Wclass-memaccess-4.C
> diff --git a/gcc/testsuite/g++.dg/Wclass-memaccess-5.C b/gcc/testsuite/g++.dg/warn/Wclass-memaccess-5.C
> similarity index 100%
> rename from gcc/testsuite/g++.dg/Wclass-memaccess-5.C
> rename to gcc/testsuite/g++.dg/warn/Wclass-memaccess-5.C
> diff --git a/gcc/testsuite/g++.dg/Wclass-memaccess-6.C b/gcc/testsuite/g++.dg/warn/Wclass-memaccess-6.C
> similarity index 100%
> rename from gcc/testsuite/g++.dg/Wclass-memaccess-6.C
> rename to gcc/testsuite/g++.dg/warn/Wclass-memaccess-6.C
> diff --git a/gcc/testsuite/g++.dg/warn/Wclass-memaccess-7.C b/gcc/testsuite/g++.dg/warn/Wclass-memaccess-7.C
> new file mode 100644
> index 00000000000..7e86b248629
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/warn/Wclass-memaccess-7.C
> @@ -0,0 +1,13 @@
> +// PR c++/105634
> +// { dg-do compile { target { c++11 } } }
> +// { dg-options "-Wall" }
> +
> +struct s
> +{
> +  struct {} a[] = 1.0; // { dg-error "" }
> +  void f (char *c)
> +  {
> +    s s;
> +    __builtin_memcpy (&s, c, sizeof(s));
> +  }
> +};
> diff --git a/gcc/testsuite/g++.dg/Wclass-memaccess.C b/gcc/testsuite/g++.dg/warn/Wclass-memaccess.C
> similarity index 100%
> rename from gcc/testsuite/g++.dg/Wclass-memaccess.C
> rename to gcc/testsuite/g++.dg/warn/Wclass-memaccess.C
> 
> base-commit: c9852156dd2fedec130f6d8eb669579ef6237946


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