[Bug target/117584] PowerPC ABI for BitInt needs to be done

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117584

--- Comment #13 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
So, regarding the #c11 issue, I had a look and e.g. on
gcc.dg/torture/bitint-102.c at -O0 that hunk is triggered on s390x-linux too (I
was testing a cross from x86_64).
--- gcc/gimple-lower-bitint.cc.jj       2026-07-28 14:13:06.606033272 +0200
+++ gcc/gimple-lower-bitint.cc  2026-07-28 16:02:01.197392027 +0200
@@ -4583,8 +4583,9 @@ bitint_large_huge::finish_arith_overflow
                             build_fold_addr_expr (unshare_expr (obj)), off);
          g = gimple_build_call (fn, 3,
                                 build_fold_addr_expr (unshare_expr (obj)),
-                                src, build_int_cst (size_type_node,
-                                                    obj_nelts * m_limb_size));
+                                build_fold_addr_expr (src),
+                                build_int_cst (size_type_node,
+                                               obj_nelts * m_limb_size));
          insert_before (g);
        }
       if (orig_obj == NULL_TREE && obj)
changes
--- bitint-102.c.272t.optimized_        2026-07-28 16:01:35.186720765 +0200
+++ bitint-102.c.272t.optimized 2026-07-28 16:02:19.056166321 +0200
@@ -211,7 +211,7 @@ int foo (signed char x, A y)

   <bb 13> :
   # _89 = PHI <0(12), 1(10), 1(11)>
-  __builtin_memmove (&bitint.12, MEM <unsigned long[8]> [(unsigned long[16]
*)&bitint.12 + 64B], 64);
+  __builtin_memmove (&bitint.12, &MEM <unsigned long[8]> [(unsigned long[16]
*)&bitint.12 + 64B], 64);
   _90 = (unsigned long) _89;
   MEM[(unsigned long *)&bitint.12 + 120B] = _90;
   MEM <unsigned long[7]> [(unsigned long[16] *)&bitint.12 + 64B] = {};
at -O0, with -O2 signficantly more, and in assembly in both cases a lot of
differences.