[Bug target/95523] aarch64:ICE in register_tuple_type，at config/aarch64/aarch64-sve-builtins.cc:3434

[z.zhanghaijian at huawei dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95523

--- Comment #2 from z.zhanghaijian at huawei dot com <z.zhanghaijian at huawei dot com> ---
(In reply to rsandifo@gcc.gnu.org from comment #1)
> The reason for the assert is that the alignment is part of the
> ABI of the types and is relied on when using LDR and STR for
> some moves.  Even though -fpack-struct=N changes the ABI in general,
> I don't think it should change it in this particular case.
> 
> I have to wonder why GCC even has -fpack-struct= though.  Do you have
> a specific need for it, or was this caught by option coverage testing?
> 
> If there is no specific need, I'd be tempted to make -fpack-struct
> unsupported for AArch64.  I think there are so many other things
> that could go wrong if it is used.

We use the option in some projects. If this option is not supported, the impact
is relatively large. I think it can make the error reporting more friendly, so
that this option can still be used normally without sve.

like:
diff --git a/gcc/config/aarch64/aarch64-sve-builtins.cc
b/gcc/config/aarch64/aarch64-sve-builtins.cc
index bdb04e8170d..e93e766aba6 100644
--- a/gcc/config/aarch64/aarch64-sve-builtins.cc
+++ b/gcc/config/aarch64/aarch64-sve-builtins.cc
@@ -3504,6 +3504,12 @@ handle_arm_sve_h ()
       return;
     }

+  if (maximum_field_alignment)
+    {
+      error ("SVE is incompatible with the use of %qs or %qs",
"-fpack-struct", "#pragma pack");
+      return;
+    }
+
   sve_switcher sve;

   /* Define the vector and tuple types.  */

Any suggestions?