Hi!
The following testcases ICE because fold_array_ctor_reference in the
RAW_DATA_CST handling just return build_int_cst without actually checking
that if type is non-NULL, TREE_TYPE (val) is uselessly convertible to it.
By falling through the code after it without *suboff += we get everything
we need, the two if conditionals will never be true (we've already
checked that size == BITS_PER_UNIT and so can't be 0, and val will be
INTEGER_CST), but it will do the important fold_ctor_reference call
which will deal with type incompatibilities.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2024-12-28 Jakub Jelinek <ja...@redhat.com>
PR tree-optimization/118207
* gimple-fold.cc (fold_array_ctor_reference): For RAW_DATA_CST,
just set val to build_int_cst and fall through to the normal
element handling code instead of returning build_int_cst right away.
* gcc.dg/pr118207.c: New test.
--- gcc/gimple-fold.cc.jj 2024-12-19 10:21:11.162403694 +0100
+++ gcc/gimple-fold.cc 2024-12-27 15:33:37.977988226 +0100
@@ -9707,9 +9707,8 @@ fold_array_ctor_reference (tree type, tr
constructor_elt *elt = CONSTRUCTOR_ELT (ctor, ctor_idx);
if (elt->index == NULL_TREE || TREE_CODE (elt->index) != INTEGER_CST)
return NULL_TREE;
- *suboff += access_index.to_uhwi () * BITS_PER_UNIT;
unsigned o = (access_index - wi::to_offset (elt->index)).to_uhwi ();
- return build_int_cst (TREE_TYPE (val), RAW_DATA_UCHAR_ELT (val, o));
+ val = build_int_cst (TREE_TYPE (val), RAW_DATA_UCHAR_ELT (val, o));
}
if (!size && TREE_CODE (val) != CONSTRUCTOR)
{
--- gcc/testsuite/gcc.dg/pr118207.c.jj 2024-12-27 15:42:09.096826118 +0100
+++ gcc/testsuite/gcc.dg/pr118207.c 2024-12-27 15:42:40.916379659 +0100
@@ -0,0 +1,25 @@
+/* PR tree-optimization/118207 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+struct A { unsigned char a; };
+struct B { struct A b; };
+static const unsigned char c[160] = {
+ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
+ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
+ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
+ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
+ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
+ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
+ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
+ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
+ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
+ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };
+struct B d;
+
+void
+foo ()
+{
+ const struct B *t = (const struct B *) &c;
+ d.b = t->b;
+}
--- gcc/testsuite/c-c++-common/cpp/embed-29.c.jj 2024-12-27
15:42:09.096826118 +0100
+++ gcc/testsuite/c-c++-common/cpp/embed-29.c 2024-12-27 15:42:40.916379659
+0100
@@ -0,0 +1,17 @@
+/* PR tree-optimization/118207 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+struct A { unsigned char a; };
+struct B { struct A b; };
+static const unsigned char c[] = {
+#embed __FILE__
+};
+struct B d;
+
+void
+foo ()
+{
+ const struct B *t = (const struct B *) &c;
+ d.b = t->b;
+}
Jakub
