c/100547 - reject overly large vector_size attributes

This rejects a number of vector components that does not fit an 'int'
which is an internal limitation of RTVEC.  This requires adjusting
gcc.dg/attr-vector_size.c which checks for much larger
supported vectors.  Note that the RTVEC limitation is a host specific
limitation (unless we change this 'int' to int32_t), but should be
32bits in practice everywhere.

2021-05-12  Richard Biener  <rguenther@suse.de>

	PR c/100547
gcc/c-family/
	* c-attribs.c (type_valid_for_vector_size): Reject too large nunits.
	Reword existing nunit diagnostic.

gcc/testsuite/
	* gcc.dg/pr100547.c: New testcase.
	* gcc.dg/attr-vector_size.c: Adjust.

3 files changed, 49 insertions, 18 deletions

diff --git a/gcc/c-family/c-attribs.c b/gcc/c-family/c-attribs.c
index f54388e..ecb32c7 100644
--- a/gcc/c-family/c-attribs.c
+++ b/gcc/c-family/c-attribs.c
@@ -4245,10 +4245,22 @@ type_valid_for_vector_size (tree type, tree atname, tree args,
   if (nunits & (nunits - 1))
     {
       if (error_p)
-	error ("number of components of the vector not a power of two");
+	error ("number of vector components %wu not a power of two", nunits);
       else
 	warning (OPT_Wattributes,
-		 "number of components of the vector not a power of two");
+		 "number of vector components %wu not a power of two", nunits);
+      return NULL_TREE;
+    }
+
+  if (nunits >= (unsigned HOST_WIDE_INT)INT_MAX)
+    {
+      if (error_p)
+	error ("number of vector components %wu exceeds %d",
+	       nunits, INT_MAX - 1);
+      else
+	warning (OPT_Wattributes,
+		 "number of vector components %wu exceeds %d",
+		 nunits, INT_MAX - 1);
       return NULL_TREE;
     }
 
diff --git a/gcc/testsuite/gcc.dg/attr-vector_size.c b/gcc/testsuite/gcc.dg/attr-vector_size.c
index 00be26a..3f2ce88 100644
--- a/gcc/testsuite/gcc.dg/attr-vector_size.c
+++ b/gcc/testsuite/gcc.dg/attr-vector_size.c
@@ -22,14 +22,6 @@ DEFVEC (extern, 30);
 
 #if __SIZEOF_SIZE_T__ > 4
 
-DEFVEC (extern, 31);
-DEFVEC (extern, 32);
-DEFVEC (extern, 33);
-DEFVEC (extern, 34);
-DEFVEC (extern, 60);
-DEFVEC (extern, 61);
-DEFVEC (extern, 62);
-
 VEC (POW2 (63)) char v63;     /* { dg-error  "'vector_size' attribute argument value '9223372036854775808' exceeds 9223372036854775807" "LP64" { target lp64 } } */
 
 #else
@@ -49,14 +41,6 @@ void test_local_scope (void)
 
 #if __SIZEOF_SIZE_T__ > 4
 
-  DEFVEC (auto, 31);
-  DEFVEC (auto, 32);
-  DEFVEC (auto, 33);
-  DEFVEC (auto, 34);
-  DEFVEC (auto, 60);
-  DEFVEC (auto, 61);
-  DEFVEC (auto, 62);
-
   VEC (POW2 (63)) char v63;   /* { dg-error  "'vector_size' attribute argument value '9223372036854775808' exceeds 9223372036854775807" "LP64" { target lp64 } } */
 
 #else
diff --git a/gcc/testsuite/gcc.dg/pr100547.c b/gcc/testsuite/gcc.dg/pr100547.c
new file mode 100644
index 0000000..2d3da4e
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr100547.c
@@ -0,0 +1,35 @@
+/* { dg-do compile { target lp64 } } */
+/* { dg-options "-O -g" } */
+
+typedef int __attribute__((vector_size(
+    ((((((((((((((((((((((((((((((8 * sizeof(short)) * sizeof(short)) *
+                                sizeof(short)) *
+                               sizeof(short)) *
+                              sizeof(short)) *
+                             sizeof(short)) *
+                            sizeof(short)) *
+                           sizeof(short)) *
+                          sizeof(short)) *
+                         sizeof(short)) *
+                        sizeof(short)) *
+                       sizeof(short)) *
+                      sizeof(short)) *
+                     sizeof(short)) *
+                    sizeof(short)) *
+                   sizeof(short)) *
+                  sizeof(short)) *
+                 sizeof(short)) *
+                sizeof(short)) *
+               sizeof(short)) *
+              sizeof(short)) *
+             sizeof(short)) *
+            sizeof(short)) *
+           sizeof(short)) *
+          sizeof(short)) *
+         sizeof(short)) *
+        sizeof(short)) *
+       sizeof(short)) *
+      sizeof(short)) *
+     sizeof(short)) *
+    sizeof(short)))) V; /* { dg-error "number of vector components" } */
+void k() { V w = { 0 }; }