mips.c (mips_cfun_call_saved_reg_p): Handle global registers.

gcc/
	* config/mips/mips.c (mips_cfun_call_saved_reg_p): Handle global
	registers.

gcc/testsuite/
	* gcc.target/mips/reg-var-1.c: New test.

From-SVN: r172616

gcc/ChangeLog

+2011-04-17  Richard Sandiford  <rdsandiford@googlemail.com>
+
+	* config/mips/mips.c (mips_cfun_call_saved_reg_p): Handle global
+	registers.
+
 2011-04-17  Jan Hubicka  <jh@suse.cz>
 
 	* cgrpah.h (struct cgraph_node): Remove finalized_by_frontend.

gcc/config/mips/mips.c

@@ -9097,6 +9097,11 @@ mips_interrupt_extra_call_saved_reg_p (unsigned int regno)
 static bool
 mips_cfun_call_saved_reg_p (unsigned int regno)
 {
+  /* If the user makes an ordinarily-call-saved register global,
+     that register is no longer call-saved.  */
+  if (global_regs[regno])
+    return false;
+
   /* Interrupt handlers need to save extra registers.  */
   if (cfun->machine->interrupt_handler_p
       && mips_interrupt_extra_call_saved_reg_p (regno))

gcc/testsuite/ChangeLog

+2011-04-17  Richard Sandiford  <rdsandiford@googlemail.com>
+
+	* gcc.target/mips/reg-var-1.c: New test.
+
 2011-04-17  Jan Hubicka  <jh@suse.cz>
 
 	* gcc.dg/winline-5.c: Update testcase.

gcc/testsuite/gcc.target/mips/reg-var-1.c

+/* { dg-do run } */
+register int g asm ("$18");
+
+void __attribute__((noinline))
+test (void)
+{
+  g = g + 1;
+}
+
+int
+main (void)
+{
+  g = 2;
+  test ();
+  return g != 3;
+}