re PR target/64580 (very high rs6000_stack_info() usage during LTO Firefox build on ppc64)

	PR target/64580
	* config.rs6000/rs6000.c (compute_vrsave_mask): Reverse loop order.
	(rs6000_stack_info): Add assert.
	(rs6000_output_savres_externs): New function, split off from...
	(rs6000_output_function_prologue): ... here.  Do not call it for
	thunks.

From-SVN: r220272

gcc/ChangeLog

+2015-01-29  Segher Boessenkool  <segher@kernel.crashing.org>
+
+	PR target/64580
+	* config.rs6000/rs6000.c (compute_vrsave_mask): Reverse loop order.
+	(rs6000_stack_info): Add assert.
+	(rs6000_output_savres_externs): New function, split off from...
+	(rs6000_output_function_prologue): ... here.  Do not call it for
+	thunks.
+
 2015-01-29  Jeff Law  <law@redhat.com>
 
-	PR target/15184 
+	PR target/15184
 	* combine.c (try_combine): If I0 is a memory load and I3 a store
 	to a related address, increase the "goodness" of doing a 4-insn
 	combination with I0-I3.

gcc/config/rs6000/rs6000.c

@@ -21145,7 +21145,7 @@ compute_vrsave_mask (void)
      them in again.  More importantly, the mask we compute here is
      used to generate CLOBBERs in the set_vrsave insn, and we do not
      wish the argument registers to die.  */
-  for (i = crtl->args.info.vregno - 1; i >= ALTIVEC_ARG_MIN_REG; --i)
+  for (i = ALTIVEC_ARG_MIN_REG; i < (unsigned) crtl->args.info.vregno; i++)
     mask &= ~ALTIVEC_REG_BIT (i);
 
   /* Similarly, remove the return value from the set.  */
@@ -21554,6 +21554,9 @@ rs6000_savres_strategy (rs6000_stack_t *info,
 static rs6000_stack_t *
 rs6000_stack_info (void)
 {
+  /* We should never be called for thunks, we are not set up for that.  */
+  gcc_assert (!cfun->is_thunk);
+
   rs6000_stack_t *info_ptr = &stack_info;
   int reg_size = TARGET_32BIT ? 4 : 8;
   int ehrd_size;
@@ -24275,11 +24278,10 @@ rs6000_emit_prologue (void)
     }
 }
 
-/* Write function prologue.  */
+/* Output .extern statements for the save/restore routines we use.  */
 
 static void
-rs6000_output_function_prologue (FILE *file,
-				 HOST_WIDE_INT size ATTRIBUTE_UNUSED)
+rs6000_output_savres_externs (FILE *file)
 {
   rs6000_stack_t *info = rs6000_stack_info ();
 
@@ -24311,6 +24313,16 @@ rs6000_output_function_prologue (FILE *file,
 	  fprintf (file, "\t.extern %s\n", name);
 	}
     }
+}
+
+/* Write function prologue.  */
+
+static void
+rs6000_output_function_prologue (FILE *file,
+				 HOST_WIDE_INT size ATTRIBUTE_UNUSED)
+{
+  if (!cfun->is_thunk)
+    rs6000_output_savres_externs (file);
 
   /* ELFv2 ABI r2 setup code and local entry point.  This must follow
      immediately after the global entry point label.  */