c-family: Handle RAW_DATA_CST in complete_array_type [PR117313]

The following testcase ICEs, because
add_flexible_array_elts_to_size -> complete_array_type
is done only after braced_lists_to_strings which optimizes
RAW_DATA_CST surrounded by INTEGER_CST into a larger RAW_DATA_CST
covering even the boundaries, while I thought it is done before
that.
So, RAW_DATA_CST now can be the last constructor_elt in a CONSTRUCTOR
and so we need the function to take it into account (handle it as
RAW_DATA_CST standing for RAW_DATA_LENGTH consecutive elements).

The function wants to support both CONSTRUCTORs without indexes and with
them (for non-RAW_DATA_CST elts it was just adding 1 for the current
index).  So, if the RAW_DATA_CST elt has ce->index, we need to add
RAW_DATA_LENGTH (ce->value) - 1, while if it doesn't (and it isn't cnt == 0
case where curindex is 0), add that plus 1, i.e. RAW_DATA_LENGTH (ce->value).

2024-10-29  Jakub Jelinek  <jakub@redhat.com>

	PR c/117313
gcc/c-family/
	* c-common.cc (complete_array_type): For RAW_DATA_CST elements
	advance curindex by RAW_DATA_LENGTH or one less than that if
	ce->index is non-NULL.  Handle even the first element if
	it is RAW_DATA_CST.  Formatting fix.
gcc/testsuite/
	* c-c++-common/init-6.c: New test.

2 files changed, 47 insertions, 7 deletions

diff --git a/gcc/c-family/c-common.cc b/gcc/c-family/c-common.cc
index 88827ac..f7feb21 100644
--- a/gcc/c-family/c-common.cc
+++ b/gcc/c-family/c-common.cc
@@ -7046,7 +7046,8 @@ complete_array_type (tree *ptype, tree initial_value, bool do_default)
 	{
 	  int eltsize
 	    = int_size_in_bytes (TREE_TYPE (TREE_TYPE (initial_value)));
-	  maxindex = size_int (TREE_STRING_LENGTH (initial_value)/eltsize - 1);
+	  maxindex = size_int (TREE_STRING_LENGTH (initial_value) / eltsize
+			       - 1);
 	}
       else if (TREE_CODE (initial_value) == CONSTRUCTOR)
 	{
@@ -7061,23 +7062,25 @@ complete_array_type (tree *ptype, tree initial_value, bool do_default)
 	  else
 	    {
 	      tree curindex;
-	      unsigned HOST_WIDE_INT cnt;
+	      unsigned HOST_WIDE_INT cnt = 1;
 	      constructor_elt *ce;
 	      bool fold_p = false;
 
 	      if ((*v)[0].index)
 		maxindex = (*v)[0].index, fold_p = true;
+	      if (TREE_CODE ((*v)[0].value) == RAW_DATA_CST)
+		cnt = 0;
 
 	      curindex = maxindex;
 
-	      for (cnt = 1; vec_safe_iterate (v, cnt, &ce); cnt++)
+	      for (; vec_safe_iterate (v, cnt, &ce); cnt++)
 		{
 		  bool curfold_p = false;
 		  if (ce->index)
 		    curindex = ce->index, curfold_p = true;
-		  else
+		  if (!ce->index || TREE_CODE (ce->value) == RAW_DATA_CST)
 		    {
-		      if (fold_p)
+		      if (fold_p || curfold_p)
 			{
 			  /* Since we treat size types now as ordinary
 			     unsigned types, we need an explicit overflow
@@ -7085,9 +7088,17 @@ complete_array_type (tree *ptype, tree initial_value, bool do_default)
 			  tree orig = curindex;
 		          curindex = fold_convert (sizetype, curindex);
 			  overflow_p |= tree_int_cst_lt (curindex, orig);
+			  curfold_p = false;
 			}
-		      curindex = size_binop (PLUS_EXPR, curindex,
-					     size_one_node);
+		      if (TREE_CODE (ce->value) == RAW_DATA_CST)
+			curindex
+			  = size_binop (PLUS_EXPR, curindex,
+					size_int (RAW_DATA_LENGTH (ce->value)
+						  - ((ce->index || !cnt)
+						     ? 1 : 0)));
+		      else
+			curindex = size_binop (PLUS_EXPR, curindex,
+					       size_one_node);
 		    }
 		  if (tree_int_cst_lt (maxindex, curindex))
 		    maxindex = curindex, fold_p = curfold_p;
diff --git a/gcc/testsuite/c-c++-common/init-6.c b/gcc/testsuite/c-c++-common/init-6.c
new file mode 100644
index 0000000..d4c323b
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/init-6.c
@@ -0,0 +1,29 @@
+/* PR c/117313 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+struct S { unsigned a; const unsigned char b[]; };
+struct S s = {
+  1,
+  { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x7e, 0x81, 0xa5,
+    0x81, 0xbd, 0x99, 0x81, 0x7e, 0x7e, 0xff, 0xdb, 0xff, 0xc3, 0xe7,
+    0xff, 0x7e, 0x6c, 0xfe, 0xfe, 0xfe, 0x7c, 0x38, 0x10, 0x00, 0x10,
+    0x38, 0x00, 0x00, 0x38, 0x6c, 0x6c, 0x38, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x18, 0x18, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x18, 0x00, 0x00, 0x00, 0x00, 0x0c, 0x0c, 0x0c, 0xec, 0x6c, 0x3c,
+  }
+};
+struct S t = {
+  2,
+  { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x7e, 0x81, 0xa5,
+    0x81, 0xbd, 0x99, 0x81, 0x7e, 0x7e, 0xff, 0xdb, 0xff, 0xc3, 0xe7,
+    0xff, 0x7e, 0x6c, 0xfe, 0xfe, 0xfe, 0x7c, 0x38, 0x10, 0x00, 0x10,
+    0x38, 0x00, 0x00, 0x38, 0x6c, 0x6c, 0x38, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x18, 0x18, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x18, 0x00, 0x00, 0x00, 0x00, 0x0c, 0x0c, 0x0c, 0xec, 0x6c, 0x3c,
+    0xff, 0x7e, 0x6c, 0xfe, 0xfe, 0xfe, 0x7c, 0x38, 0x10, 0x00, 0x10,
+    0x38, 0x00, 0x00, 0x38, 0x6c, 0x6c, 0x38, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x18, 0x18, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x18, 0x00, 0x00, 0x00, 0x00, 0x0c, 0x0c, 0x0c, 0xec, 0x6c, 0x3c
+  }
+};