middle-end/121216 - ICE with VLA const string initializer

constant_byte_string fails to consider the string type might be VLA
when initialized by an empty string CTOR.

	PR middle-end/121216
	* expr.cc (constant_byte_string): Check the string type
	size fits an uhwi before converting to uhwi.

	* gcc.dg/pr121216.c: New testcase.

diff --git a/gcc/expr.cc b/gcc/expr.cc
index ac4fdfaa2181e4d64444c5c37006939b4c70b85e..3f2b121ee038faa527e39f128f5a30a0ff380c5d 100644 (file)
--- a/gcc/expr.cc
+++ b/gcc/expr.cc
@@ -13206,6 +13206,8 @@ constant_byte_string (tree arg, tree *ptr_offset, tree *mem_size, tree *decl,
             of the expected type and size.  */
          if (!initsize)
            initsize = integer_zero_node;
+         else if (!tree_fits_uhwi_p (initsize))
+           return NULL_TREE;
 
          unsigned HOST_WIDE_INT size = tree_to_uhwi (initsize);
          if (size > (unsigned HOST_WIDE_INT) INT_MAX)

diff --git a/gcc/testsuite/gcc.dg/pr121216.c b/gcc/testsuite/gcc.dg/pr121216.c
new file mode 100644 (file)
index 0000000..a695b40
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr121216.c
@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+int foo (void)
+{
+    const char *key = "obscurelevelofabstraction";
+    const char reverse_key[__builtin_strlen(key)] = {'\0'}; /* { dg-error "variable-sized object may not be initialized except with an empty initializer" } */
+    return __builtin_strlen(reverse_key);
+}