PR middle-end/88956 - ICE: Floating point exception on a memcpy from

PR middle-end/88956 - ICE: Floating point exception on a memcpy from
a zero-length constant array

gcc/ChangeLog:

	PR c/88956
	* gimple-fold.c (fold_array_ctor_reference): Avoid zero-length arrays.

gcc/testsuite/ChangeLog:

	PR c/88956
	* gcc.dg/Warray-bounds-39.c: New test.

From-SVN: r268378

4 files changed, 168 insertions, 8 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 4c5c47a..d040d97 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2019-01-29  Martin Sebor  <msebor@redhat.com>
+
+	PR c/88956
+	* gimple-fold.c (fold_array_ctor_reference): Avoid zero-length arrays.
+
 2019-01-29  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/66676
diff --git a/gcc/gimple-fold.c b/gcc/gimple-fold.c
index 500e551..7ef5004 100644
--- a/gcc/gimple-fold.c
+++ b/gcc/gimple-fold.c
@@ -6702,25 +6702,27 @@ fold_array_ctor_reference (tree type, tree ctor,
     domain_type = TYPE_DOMAIN (TREE_TYPE (ctor));
   if (domain_type && TYPE_MIN_VALUE (domain_type))
     {
-      /* Static constructors for variably sized objects makes no sense.  */
+      /* Static constructors for variably sized objects make no sense.  */
       if (TREE_CODE (TYPE_MIN_VALUE (domain_type)) != INTEGER_CST)
 	return NULL_TREE;
       low_bound = wi::to_offset (TYPE_MIN_VALUE (domain_type));
     }
   else
     low_bound = 0;
-  /* Static constructors for variably sized objects makes no sense.  */
+  /* Static constructors for variably sized objects make no sense.  */
   if (TREE_CODE (TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (ctor)))) != INTEGER_CST)
     return NULL_TREE;
   elt_size = wi::to_offset (TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (ctor))));
 
   /* When TYPE is non-null, verify that it specifies a constant-sized
-     accessed not larger than size of array element.  */
-  if (type
-      && (!TYPE_SIZE_UNIT (type)
-	  || TREE_CODE (TYPE_SIZE_UNIT (type)) != INTEGER_CST
-	  || elt_size < wi::to_offset (TYPE_SIZE_UNIT (type))
-	  || elt_size == 0))
+     accessed not larger than size of array element.  Avoid division
+     by zero below when ELT_SIZE is zero, such as with the result of
+     an initializer for a zero-length array or an empty struct.  */
+  if (elt_size == 0
+      || (type
+	  && (!TYPE_SIZE_UNIT (type)
+	      || TREE_CODE (TYPE_SIZE_UNIT (type)) != INTEGER_CST
+	      || elt_size < wi::to_offset (TYPE_SIZE_UNIT (type)))))
     return NULL_TREE;
 
   /* Compute the array index we look for.  */
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 5387957..b7566db 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2019-01-29  Martin Sebor  <msebor@redhat.com>
+
+	PR c/88956
+	* gcc.dg/Warray-bounds-39.c: New test.
+
 2019-01-29  Marek Polacek  <polacek@redhat.com>
 
 	PR testsuite/89110
diff --git a/gcc/testsuite/gcc.dg/Warray-bounds-39.c b/gcc/testsuite/gcc.dg/Warray-bounds-39.c
new file mode 100644
index 0000000..6a441c7
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Warray-bounds-39.c
@@ -0,0 +1,148 @@
+/* PR middle-end/88956 - ICE: Floating point exception on a memcpy from
+   an zero-length constant array
+   Verify both that memory and string calls with a zero-length array
+   don't cause an ICE, and also that they emit warnings.
+   { dg-do compile }
+   { dg-options "-O2 -Wall" }  */
+
+typedef __SIZE_TYPE__ size_t;
+
+extern void* memcpy (void*, const void*, size_t);
+extern void* memmove (void*, const void*, size_t);
+extern char* strcpy (char*, const char*);
+extern char* strncpy (char*, const char*, size_t);
+
+const char s0[0] = { };
+const char s0_0[0][0] = { };
+const char s0_1[0][1] = { };
+const char s1_0[1][0] = { };
+
+char d[4];
+
+void* test_memcpy_s0_1 (void *d)
+{
+  return memcpy (d, s0, 1);       /* { dg-warning "\\\[-Warray-bounds" } */
+}
+
+void* test_memcpy_s0_2 (void *d)
+{
+  return memcpy (d, s0, 2);       /* { dg-warning "\\\[-Warray-bounds" } */
+}
+
+void* test_memcpy_s0_0_1 (void *d)
+{
+  return memcpy (d, s0_0, 1);     /* { dg-warning "\\\[-Warray-bounds" } */
+}
+
+void* test_memcpy_s0_0_2 (void *d)
+{
+  return memcpy (d, s0_0, 2);     /* { dg-warning "\\\[-Warray-bounds" } */
+}
+
+
+void* test_memcpy_s0_1_1 (void *d)
+{
+  return memcpy (d, s0_1, 1);     /* { dg-warning "\\\[-Warray-bounds" } */
+}
+
+void* test_memcpy_s0_1_2 (void *d)
+{
+  return memcpy (d, s0_1, 2);     /* { dg-warning "\\\[-Warray-bounds" } */
+}
+
+
+void* test_memcpy_s1_0_1 (void *d)
+{
+  return memcpy (d, s1_0, 1);     /* { dg-warning "\\\[-Warray-bounds" } */
+}
+
+void* test_memcpy_s1_0_2 (void *d)
+{
+  return memcpy (d, s1_0, 2);     /* { dg-warning "\\\[-Warray-bounds" } */
+}
+
+
+void* test_memmove_s0_1 (void *d)
+{
+  return memmove (d, s0, 1);      /* { dg-warning "\\\[-Warray-bounds" } */
+}
+
+void* test_memmove_s0_2 (void *d)
+{
+  return memmove (d, s0, 2);      /* { dg-warning "\\\[-Warray-bounds" } */
+}
+
+void* test_memmove_s0_0_1 (void *d)
+{
+  return memmove (d, s0_0, 1);    /* { dg-warning "\\\[-Warray-bounds" } */
+}
+
+void* test_memmove_s0_0_2 (void *d)
+{
+  return memmove (d, s0_0, 2);    /* { dg-warning "\\\[-Warray-bounds" } */
+}
+
+
+struct Empty { };
+const struct Empty e = { };
+const struct Empty e0[0] = { };
+const struct Empty e0_0[0][0] = { };
+const struct Empty e0_1[0][1] = { };
+const struct Empty e1_0[1][0] = { };
+
+void* test_memcpy_e_1 (void *d)
+{
+  return memcpy (d, &e, 1);       /* { dg-warning "\\\[-Warray-bounds" } */
+}
+
+void* test_memcpy_e0_1 (void *d)
+{
+  return memcpy (d, e0, 1);       /* { dg-warning "\\\[-Warray-bounds" } */
+}
+
+void* test_memcpy_e0_0_1 (void *d)
+{
+  return memcpy (d, e0_0, 1);     /* { dg-warning "\\\[-Warray-bounds" } */
+}
+
+void* test_memcpy_e0_1_1 (void *d)
+{
+  return memcpy (d, e0_1, 1);     /* { dg-warning "\\\[-Warray-bounds" } */
+}
+
+void* test_memcpy_e1_0_1 (void *d)
+{
+  return memcpy (d, e1_0, 1);     /* { dg-warning "\\\[-Warray-bounds" } */
+}
+
+
+char* test_strcpy_s0 (char *d)
+{
+  return strcpy (d, s0);          /* { dg-warning "\\\[-Warray-bounds" "pr88991" { xfail *-*-* } } */
+}
+
+char* test_strcpy_s0_0 (char *d)
+{
+  return strcpy (d, s0_0[0]);     /* { dg-warning "\\\[-Warray-bounds" "pr88991" { xfail *-*-* } } */
+}
+
+
+char* test_strncpy_s0_1 (char *d)
+{
+  return strncpy (d, s0, 1);    /* { dg-warning "\\\[-Warray-bounds" "pr88991" { xfail *-*-* } } */
+}
+
+char* test_strncpy_s0_2 (char *d)
+{
+  return strncpy (d, s0, 2);    /* { dg-warning "\\\[-Warray-bounds" "pr88991" { xfail *-*-* } } */
+}
+
+char* test_strncpy_s0_0_1 (char *d)
+{
+  return strncpy (d, s0_0[0], 1); /* { dg-warning "\\\[-Warray-bounds" "pr88991" { xfail *-*-* } } */
+}
+
+char* test_strncpy_s0_0_2 (char *d)
+{
+  return strncpy (d, s0_0[0], 2); /* { dg-warning "\\\[-Warray-bounds" "pr88991" { xfail *-*-* } } */
+}