[gcc r14-8373] c: Call c_fully_fold on __atomic_* operands in atomic_bitint_fetch_using_cas_loop [PR113518]

[Jakub Jelinek <jakub@gcc.gnu.org>]

https://gcc.gnu.org/g:dbc5f1f523b3cfa539d72fdd60b9479b3cd5a45d

commit r14-8373-gdbc5f1f523b3cfa539d72fdd60b9479b3cd5a45d
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Tue Jan 23 19:59:00 2024 +0100

    c: Call c_fully_fold on __atomic_* operands in atomic_bitint_fetch_using_cas_loop [PR113518]
    
    As the following testcase shows, I forgot to call c_fully_fold on the
    __atomic_*/__sync_* operands called on _BitInt address, the expressions
    are then used inside of TARGET_EXPR initializers etc. and are never fully
    folded later, which means we can ICE e.g. on C_MAYBE_CONST_EXPR trees
    inside of those.
    
    The following patch fixes it, while the function currently is only called
    in the C FE because C++ doesn't support BITINT_TYPE, I think guarding the
    calls on !c_dialect_cxx () is safer.
    
    2024-01-23  Jakub Jelinek  <jakub@redhat.com>
    
            PR c/113518
            * c-common.cc (atomic_bitint_fetch_using_cas_loop): Call c_fully_fold
            on lhs_addr, val and model for C.
    
            * gcc.dg/bitint-77.c: New test.

Diff:
---
 gcc/c-family/c-common.cc         |  6 ++++++
 gcc/testsuite/gcc.dg/bitint-77.c | 25 +++++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/gcc/c-family/c-common.cc b/gcc/c-family/c-common.cc
index dc67562ce92..e15eff698df 100644
--- a/gcc/c-family/c-common.cc
+++ b/gcc/c-family/c-common.cc
@@ -8082,6 +8082,12 @@ atomic_bitint_fetch_using_cas_loop (location_t loc,
   tree lhs_addr = (*orig_params)[0];
   tree val = convert (nonatomic_lhs_type, (*orig_params)[1]);
   tree model = convert (integer_type_node, (*orig_params)[2]);
+  if (!c_dialect_cxx ())
+    {
+      lhs_addr = c_fully_fold (lhs_addr, false, NULL);
+      val = c_fully_fold (val, false, NULL);
+      model = c_fully_fold (model, false, NULL);
+    }
   if (TREE_SIDE_EFFECTS (lhs_addr))
     {
       tree var = create_tmp_var_raw (TREE_TYPE (lhs_addr));
diff --git a/gcc/testsuite/gcc.dg/bitint-77.c b/gcc/testsuite/gcc.dg/bitint-77.c
new file mode 100644
index 00000000000..0125f1e9fb3
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/bitint-77.c
@@ -0,0 +1,25 @@
+/* PR c/113518 */
+/* { dg-do compile { target bitint } } */
+/* { dg-options "-O2 -std=c23" } */
+
+#if __BITINT_MAXWIDTH__ >= 607
+_BitInt(607) v;
+#else
+_BitInt(63) v;
+#endif
+
+void
+foo (void)
+{
+  __atomic_fetch_or (&v, 1 << 31, __ATOMIC_RELAXED);
+}
+
+#if __BITINT_MAXWIDTH__ >= 16321
+_BitInt(16321) w;
+
+void
+bar (void)
+{
+  __atomic_fetch_add (&w, 1 << 31, __ATOMIC_SEQ_CST);
+}
+#endif