re PR target/22362 (static function calls and global register variables)

	PR target/22362
	* config/i386/i386.c (ix86_function_regparm): Make sure automatic regparm
	for internal functions doesn't use registers used by global registers
	variables.  Use fewer register parameters if there are global register
	variables.

	* gcc.target/i386/pr22362.c: New test.

From-SVN: r103964

gcc/ChangeLog

+2005-09-06  Jakub Jelinek  <jakub@redhat.com>
+
+	PR target/22362
+	* config/i386/i386.c (ix86_function_regparm): Make sure automatic regparm
+	for internal functions doesn't use registers used by global registers
+	variables.  Use fewer register parameters if there are global register
+	variables.
+
 2005-09-06  Olivier Hainque  <hainque@adacore.com>
             Eric Botcazou  <ebotcazou@adacore.com>
 

gcc/config/i386/i386.c

@@ -2148,12 +2148,29 @@ ix86_function_regparm (tree type, tree decl)
 	  struct cgraph_local_info *i = cgraph_local_info (decl);
 	  if (i && i->local)
 	    {
+	      int local_regparm, globals = 0, regno;
+
+	      /* Make sure no regparm register is taken by a global register
+		 variable.  */
+	      for (local_regparm = 0; local_regparm < 3; local_regparm++)
+		if (global_regs[local_regparm])
+		  break;
 	      /* We can't use regparm(3) for nested functions as these use
 		 static chain pointer in third argument.  */
-	      if (DECL_CONTEXT (decl) && !DECL_NO_STATIC_CHAIN (decl))
-		regparm = 2;
-	      else
-		regparm = 3;
+	      if (local_regparm == 3
+		  && DECL_CONTEXT (decl) && !DECL_NO_STATIC_CHAIN (decl))
+		local_regparm = 2;
+	      /* Each global register variable increases register preassure,
+		 so the more global reg vars there are, the smaller regparm
+		 optimization use, unless requested by the user explicitly.  */
+	      for (regno = 0; regno < 6; regno++)
+		if (global_regs[regno])
+		  globals++;
+	      local_regparm
+		= globals < local_regparm ? local_regparm - globals : 0;
+
+	      if (local_regparm > regparm)
+		regparm = local_regparm;
 	    }
 	}
     }

gcc/testsuite/ChangeLog

 2005-09-06  Jakub Jelinek  <jakub@redhat.com>
 
+	PR target/22362
+	* gcc.target/i386/pr22362.c: New test.
+
 	PR rtl-optimization/23098
 	* gcc.target/i386/pr23098.c: Add dg-require-effective-target ilp32.
 

gcc/testsuite/gcc.target/i386/pr22362.c

+/* PR target/22362 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+/* { dg-require-effective-target ilp32 } */
+
+register unsigned int reg0 __asm__ ("esi");
+register unsigned int reg1 __asm__ ("edi");
+register unsigned int reg2 __asm__ ("ebx");
+
+static unsigned int
+__attribute__((noinline))
+foo (unsigned long *x, void *y, void *z)
+{
+  int i;
+
+  for (i = 5; i > 0; i--)
+    x[i] = (unsigned long) foo ((unsigned long *) x[i], y, z);
+  return 0;
+}
+
+unsigned int
+bar (void)
+{
+  return foo (0, 0, 0);
+}