Re: [PATCH] rs6000: Handle pcrel sibcalls to longcall functions [PR104894]

[Peter Bergner via Gcc-patches]

On 4/5/22 10:33 PM, Peter Bergner via Gcc-patches wrote:
> On 4/5/22 5:32 PM, Segher Boessenkool wrote:
>> On Tue, Apr 05, 2022 at 05:06:50PM -0500, Peter Bergner wrote:
>>>  
>>> +  /* Handle longcall attributes.  */
>>> +  if ((INTVAL (cookie) & CALL_LONG) != 0
>>> +      && GET_CODE (func_desc) == SYMBOL_REF)
>>
>> Don't say "!= 0" here please.
>>
>>   if (INTVAL (cookie) & CALL_LONG && SYMBOL_REF_P (func_desc))
> 
> Yes, cut & paste.  I'll change it.
[snip]
>> Don't say "Only", it is the "New" syndrome: it is out of date before you
>> know it :-(  You can just leave it away here.
> 
> Ok, I can drop "Only" and keep the rest the same.

So the updated change looks like below with the ChangeLog entry and tests being 
the same:

Is this better and ok for trunk?

Peter


@@ -25659,11 +25659,20 @@ rs6000_sibcall_aix (rtx value, rtx func_desc, rtx 
tlsarg, rtx cookie)
   rtx r12 = NULL_RTX;
   rtx func_addr = func_desc;
 
-  gcc_assert (INTVAL (cookie) == 0);
-
   if (global_tlsarg)
     tlsarg = global_tlsarg;
 
+  /* Handle longcall attributes.  */
+  if (INTVAL (cookie) & CALL_LONG && SYMBOL_REF_P (func_desc))
+    {
+      /* PCREL can do a sibling call to a longcall function
+        because we don't need to restore the TOC register.  */
+      gcc_assert (rs6000_pcrel_p ());
+      func_desc = rs6000_longcall_ref (func_desc, tlsarg);
+    }
+  else
+    gcc_assert (INTVAL (cookie) == 0);
+
   /* For ELFv2, r12 and CTR need to hold the function address
      for an indirect call.  */
   if (GET_CODE (func_desc) != SYMBOL_REF && DEFAULT_ABI == ABI_ELFv2)