https://gcc.gnu.org/g:6acf9501771b8a26643fe6b887eb2d9b6d008b47
commit r16-2436-g6acf9501771b8a26643fe6b887eb2d9b6d008b47
Author: Richard Biener <rguent...@suse.de>
Date: Tue Jul 22 15:41:20 2025 +0200
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:
---
gcc/expr.cc | 2 ++
gcc/testsuite/gcc.dg/pr121216.c | 9 +++++++++
2 files changed, 11 insertions(+)
diff --git a/gcc/expr.cc b/gcc/expr.cc
index ac4fdfaa2181..3f2b121ee038 100644
--- 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
index 000000000000..a695b40d12dc
--- /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);
+}
