From: Marek Polacek <polacek@redhat.com>
Date: Tue, 17 May 2022 19:13:58 +0000 (-0400)
Subject: c++: fix SIGFPE with -Wclass-memaccess [PR105634]
X-Git-Tag: basepoints/gcc-14~6586
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=dfe38b8d5dbfe3dd5209aece4ce2f7a6b303a2f9;p=thirdparty%2Fgcc.git

c++: fix SIGFPE with -Wclass-memaccess [PR105634]

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.

	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.
---

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