[PATCH][V4] rs6000: Remove unnecessary option manipulation.

[Martin Liska <mliska@suse.cz>]

Do not set flag_rename_registers, it's already enabled with EnabledBy(funroll-loops)
in the common.opt file. Use EnabledBy for unroll_only_small_loops which
is a canonical approach how can be make option dependencies.

gcc/ChangeLog:

	* config/rs6000/rs6000.c (rs6000_override_options_after_change):
	Do not set flag_rename_registers and unroll_only_small_loops.
	* config/rs6000/rs6000.opt: Use EnabledBy for unroll_only_small_loops.
---
 gcc/config/rs6000/rs6000.c   | 7 +------
 gcc/config/rs6000/rs6000.opt | 2 +-
 2 files changed, 2 insertions(+), 7 deletions(-)

diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index e4843eb0f1c..5550113a94c 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -3466,13 +3466,8 @@ rs6000_override_options_after_change (void)
   /* Explicit -funroll-loops turns -munroll-only-small-loops off, and
      turns -frename-registers on.  */
   if ((OPTION_SET_P (flag_unroll_loops) && flag_unroll_loops)
-       || (OPTION_SET_P (flag_unroll_all_loops)
-	   && flag_unroll_all_loops))
+       || (OPTION_SET_P (flag_unroll_all_loops) && flag_unroll_all_loops))
     {
-      if (!OPTION_SET_P (unroll_only_small_loops))
-	unroll_only_small_loops = 0;
-      if (!OPTION_SET_P (flag_rename_registers))
-	flag_rename_registers = 1;
       if (!OPTION_SET_P (flag_cunroll_grow_size))
 	flag_cunroll_grow_size = 1;
     }
diff --git a/gcc/config/rs6000/rs6000.opt b/gcc/config/rs6000/rs6000.opt
index 9d7878f144a..faeb7423ca7 100644
--- a/gcc/config/rs6000/rs6000.opt
+++ b/gcc/config/rs6000/rs6000.opt
@@ -546,7 +546,7 @@ Target Undocumented Var(rs6000_optimize_swaps) Init(1) Save
 Analyze and remove doubleword swaps from VSX computations.
 
 munroll-only-small-loops
-Target Undocumented Var(unroll_only_small_loops) Init(0) Save
+Target Undocumented Var(unroll_only_small_loops) Init(0) Save EnabledBy(funroll-loops)
 ; Use conservative small loop unrolling.
 
 mpower9-misc
-- 
2.33.1