re PR target/35504 (incorrect code generated on i386 for C++ multiple…

re PR target/35504 (incorrect code generated on i386 for C++ multiple inheritance, large return structures and regparm or fastcall calling conventions)

        PR target/35504
        * config/i386/i386.c (x86_this_parameter): Calculate correct location
        of "this" pointer when "regparm = N" or "fastcall" is in effect.

testsuite/ChangeLog

        PR target/35504
        * g++.dg/other/pr35504.C: New test.

From-SVN: r133324

gcc/ChangeLog

+2008-03-18  Mikulas Patocka  <mikulas@artax.karlin.mff.cuni.cz>
+
+	PR target/35504
+	* config/i386/i386.c (x86_this_parameter): Calculate correct location
+	of "this" pointer when "regparm = N" or "fastcall" is in effect.
+
 2008-03-18  Ralf Wildenhues  <Ralf.Wildenhues@gmx.de>
 
 	* doc/include/texinfo.tex: Update to version 2008-03-17.10.

gcc/config/i386/i386.c

@@ -22698,6 +22698,7 @@ x86_this_parameter (tree function)
 {
   tree type = TREE_TYPE (function);
   bool aggr = aggregate_value_p (TREE_TYPE (type), type) != 0;
+  int nregs;
 
   if (TARGET_64BIT)
     {
@@ -22710,11 +22711,25 @@ x86_this_parameter (tree function)
       return gen_rtx_REG (DImode, parm_regs[aggr]);
     }
 
-  if (ix86_function_regparm (type, function) > 0 && !stdarg_p (type))
+  nregs = ix86_function_regparm (type, function);
+
+  if (nregs > 0 && !stdarg_p (type))
     {
-      int regno = AX_REG;
+      int regno;
+
       if (lookup_attribute ("fastcall", TYPE_ATTRIBUTES (type)))
-	regno = CX_REG;
+	regno = aggr ? DX_REG : CX_REG;
+      else
+        {
+	  regno = AX_REG;
+	  if (aggr)
+	    {
+	      regno = DX_REG;
+	      if (nregs == 1)
+		return gen_rtx_MEM (SImode,
+				    plus_constant (stack_pointer_rtx, 4));
+	    }
+	}
       return gen_rtx_REG (SImode, regno);
     }
 

gcc/testsuite/ChangeLog

+2008-03-18  Mikulas Patocka  <mikulas@artax.karlin.mff.cuni.cz>
+
+	PR target/35504
+	* g++.dg/other/pr35504.C: New test.
+
 2008-03-18  Richard Guenther  <rguenther@suse.de>
 
 	* gcc.dg/tree-ssa/forwprop-4.c: New testcase.

gcc/testsuite/g++.dg/other/pr35504.C

+// { dg-do run { target { { i?86-*-* x86_64-*-* } && ilp32 } } }
+
+#define ATTR0 __attribute__((__regparm__(0)))
+#define ATTR1 __attribute__((__regparm__(1)))
+#define ATTR2 __attribute__((__regparm__(2)))
+#define ATTR3 __attribute__((__regparm__(3)))
+#define ATTR4 __attribute__((__fastcall__))
+#define ATTR5 __attribute__((__stdcall__))
+#define ATTR6 __attribute__((__cdecl__))
+#define ATTR7
+
+extern "C" void abort (void);
+
+struct long_struct
+{
+  int a[3];
+};
+
+struct long_struct ret;
+
+class c3 *this3;
+
+class c1
+{
+  int val1;
+public:
+    virtual void foo () { }
+};
+
+class c2
+{
+public:
+  virtual ATTR0 struct long_struct method0 ()
+  {
+    return ret;
+  }
+
+  virtual ATTR1 struct long_struct method1 ()
+  {
+    return ret;
+  }
+
+  virtual ATTR2 struct long_struct method2 ()
+  {
+    return ret;
+  }
+
+  virtual ATTR3 struct long_struct method3 ()
+  {
+    return ret;
+  }
+
+  virtual ATTR4 struct long_struct method4 ()
+  {
+    return ret;
+  }
+
+  virtual ATTR5 struct long_struct method5 ()
+  {
+    return ret;
+  }
+
+  virtual ATTR6 struct long_struct method6 ()
+  {
+    return ret;
+  }
+
+  virtual ATTR7 struct long_struct method7 ()
+  {
+    return ret;
+  }
+};
+
+class c3:c1, public c2
+{
+public:
+  c3 ()
+  {
+    this3 = this;
+  }
+
+  struct long_struct check_this (int a)
+  {
+    if (this3 != this)
+      abort ();
+
+    return ret;
+  }
+
+  virtual ATTR0 struct long_struct method0 ()
+  {
+    return check_this (0);
+  }
+
+  virtual ATTR1 struct long_struct method1 ()
+  {
+    return check_this (1);
+  }
+
+  virtual ATTR2 struct long_struct method2 ()
+  {
+    return check_this (2);
+  }
+
+  virtual ATTR3 struct long_struct method3 ()
+  {
+    return check_this (3);
+  }
+
+  virtual ATTR4 struct long_struct method4 ()
+  {
+    return check_this (4);
+  }
+
+  virtual ATTR5 struct long_struct method5 ()
+  {
+    return check_this (5);
+  }
+
+  virtual ATTR6 struct long_struct method6 ()
+  {
+    return check_this (6);
+  }
+
+  virtual ATTR7 struct long_struct method7 ()
+  {
+    return check_this (7);
+  }
+};
+
+class c3 c3_instance;
+class c2 *c2_ptr = &c3_instance;
+
+int
+main ()
+{
+  c2_ptr->method0 ();
+  c2_ptr->method1 ();
+  c2_ptr->method2 ();
+  c2_ptr->method3 ();
+  c2_ptr->method4 ();
+  c2_ptr->method5 ();
+  c2_ptr->method6 ();
+  c2_ptr->method7 ();
+
+  return 0;
+}