RFA: Switching LRA on for s390

[Vladimir Makarov]

   The following patch switches LRA on for s390.  The patch introduces
a new option -mlra to use LRA instead of reload.  I did not document
the option as I'd like to delete it for gcc4.9.  By default, LRA will
be used for s390 instead of reload for better testing LRA for s390.

   Changes in s390.md are because of define_splits for the last
alternative *movmem_short, *clrmem_short, *cmpmem_short have guard
TARGET_CPU_ZARCH.

   The patch was successfully bootstrapped and tested on s390x.

   Any comments?
   Is it ok to commit the patch into trunk?

   Thanks.


2013-05-31  Vladimir Makarov  <vmakarov@redhat.com>

     * config/s390/s390.opt (mlra): New option.
     * config/s390/s390.c (s390_decompose_address): Check displacement
     for all registers for LRA.
     (s390_secondary_reload): Don't used secondary reloads for LRA.
     (s390_lra_p): New function.
     (TARGET_LRA_P): Define.
     * config/s390/s390.md (*movmem_short, *clrmem_short): Change value
     of attribute cpu_facility to zarch for the last alternative.
     (*cmpmem_short): Ditto.


-------------- next part --------------
Index: config/s390/s390.c
===================================================================
--- config/s390/s390.c	(revision 199453)
+++ config/s390/s390.c	(working copy)
@@ -2017,14 +2017,18 @@ s390_decompose_address (rtx addr, struct
 	 Thus we don't check the displacement for validity here.  If after
 	 elimination the displacement turns out to be invalid after all,
 	 this is fixed up by reload in any case.  */
-      if (base != arg_pointer_rtx
-	  && indx != arg_pointer_rtx
-	  && base != return_address_pointer_rtx
-	  && indx != return_address_pointer_rtx
-	  && base != frame_pointer_rtx
-	  && indx != frame_pointer_rtx
-	  && base != virtual_stack_vars_rtx
-	  && indx != virtual_stack_vars_rtx)
+      /* LRA maintains always displacements up to date and we need to
+	 know the displacement is right during all LRA not only at the
+	 final elimination.  */
+      if (lra_in_progress
+	  || (base != arg_pointer_rtx
+	      && indx != arg_pointer_rtx
+	      && base != return_address_pointer_rtx
+	      && indx != return_address_pointer_rtx
+	      && base != frame_pointer_rtx
+	      && indx != frame_pointer_rtx
+	      && base != virtual_stack_vars_rtx
+	      && indx != virtual_stack_vars_rtx))
 	if (!DISP_IN_RANGE (offset))
 	  return false;
     }
@@ -3189,7 +3193,9 @@ s390_secondary_reload (bool in_p, rtx x,
 
   /* We need a scratch register when loading a PLUS expression which
      is not a legitimate operand of the LOAD ADDRESS instruction.  */
-  if (in_p && s390_plus_operand (x, mode))
+  /* LRA can deal with transformation of plus op very well -- so we
+     don't need to prompt LRA in this case.  */
+  if (! lra_in_progress && in_p && s390_plus_operand (x, mode))
     sri->icode = (TARGET_64BIT ?
 		  CODE_FOR_reloaddi_plus : CODE_FOR_reloadsi_plus);
 
@@ -7868,6 +7874,13 @@ s390_class_max_nregs (enum reg_class rcl
   return (GET_MODE_SIZE (mode) + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
 }
 
+/* Return true if we use LRA instead of reload pass.  */
+static bool
+s390_lra_p (void)
+{
+  return s390_lra_flag;
+}
+
 /* Return true if register FROM can be eliminated via register TO.  */
 
 static bool
@@ -11105,6 +11118,9 @@ s390_loop_unroll_adjust (unsigned nunrol
 #undef TARGET_LEGITIMATE_CONSTANT_P
 #define TARGET_LEGITIMATE_CONSTANT_P s390_legitimate_constant_p
 
+#undef TARGET_LRA_P
+#define TARGET_LRA_P s390_lra_p
+
 #undef TARGET_CAN_ELIMINATE
 #define TARGET_CAN_ELIMINATE s390_can_eliminate
 
Index: config/s390/s390.md
===================================================================
--- config/s390/s390.md	(revision 199453)
+++ config/s390/s390.md	(working copy)
@@ -2690,7 +2690,7 @@
   "(GET_MODE (operands[2]) == Pmode || GET_MODE (operands[2]) == VOIDmode)"
   "#"
   [(set_attr "type"         "cs")
-   (set_attr "cpu_facility" "*,*,z10,*")])
+   (set_attr "cpu_facility" "*,*,z10,zarch")])
 
 (define_split
   [(set (match_operand:BLK 0 "memory_operand" "")
@@ -2899,7 +2899,7 @@
   "(GET_MODE (operands[1]) == Pmode || GET_MODE (operands[1]) == VOIDmode)"
   "#"
   [(set_attr "type" "cs")
-   (set_attr "cpu_facility" "*,*,z10,*")])
+   (set_attr "cpu_facility" "*,*,z10,zarch")])
 
 (define_split
   [(set (match_operand:BLK 0 "memory_operand" "")
@@ -3075,7 +3075,7 @@
   "(GET_MODE (operands[2]) == Pmode || GET_MODE (operands[2]) == VOIDmode)"
   "#"
   [(set_attr "type" "cs")
-   (set_attr "cpu_facility" "*,*,z10,*")])
+   (set_attr "cpu_facility" "*,*,z10,zarch")])
 
 (define_split
   [(set (reg:CCU CC_REGNUM)
Index: config/s390/s390.opt
===================================================================
--- config/s390/s390.opt	(revision 199453)
+++ config/s390/s390.opt	(working copy)
@@ -149,3 +149,7 @@ Target Report Joined RejectNegative UInt
 Set the branch costs for conditional branch instructions.  Reasonable
 values are small, non-negative integers.  The default branch cost is
 1.
+
+mlra
+Target Report Var(s390_lra_flag) Init(1) Save
+Use LRA instead of reload