[16/32] Remove global call sets: function.c

[Richard Sandiford]

Whatever the rights and wrongs of the way aggregate_value_p
handles call-preserved registers, it's a de facto part of the ABI,
so we shouldn't change it.  The patch simply extends the current
approach to whatever call-preserved set the function happens to
be using.


2019-09-11  Richard Sandiford  <richard.sandif...@arm.com>

gcc/
        * function.c (aggregate_value_p): Work out which ABI the
        function is using before testing which registers are at least
        partly preserved by a call.

Index: gcc/function.c
===================================================================
--- gcc/function.c      2019-09-11 19:47:07.490381964 +0100
+++ gcc/function.c      2019-09-11 19:48:18.357882573 +0100
@@ -2120,10 +2120,17 @@ aggregate_value_p (const_tree exp, const
   if (!REG_P (reg))
     return 0;
 
+  /* Use the default ABI if the type of the function isn't known.
+     The scheme for handling interoperability between different ABIs
+     requires us to be able to tell when we're calling a function with
+     a nondefault ABI.  */
+  const predefined_function_abi &abi = (fntype
+                                       ? fntype_abi (fntype)
+                                       : default_function_abi);
   regno = REGNO (reg);
   nregs = hard_regno_nregs (regno, TYPE_MODE (type));
   for (i = 0; i < nregs; i++)
-    if (! call_used_or_fixed_reg_p (regno + i))
+    if (!fixed_regs[regno + i] && !abi.clobbers_full_reg_p (regno + i))
       return 1;
 
   return 0;