Slight PA codegen improvement

[Jeffrey A Law <law at cygnus dot com>]

This slightly improves code generation for certain integer sequences by
reducing the latency of shift-add sequence, even if the result of the
shift without addition is needed elsewhere.

Sat Jan 16 15:13:46 1999  Jeffrey A Law  (law@cygnus.com)

        * pa.md (shadd): Create shadd insns, even if the result of the shift is
        needed without the addition.

Index: config/pa/pa.md
===================================================================
RCS file: /egcs/carton/cvsfiles/egcs/gcc/config/pa/pa.md,v
retrieving revision 1.17
diff -c -3 -p -r1.17 pa.md
*** pa.md	1999/01/03 20:09:30	1.17
--- pa.md	1999/01/16 22:17:59
***************
*** 3627,3632 ****
--- 3627,3668 ----
    [(set_attr "type" "binary")
     (set_attr "length" "4")])
  
+ ;; This anonymous pattern and splitter wins because it reduces the latency
+ ;; of the shadd sequence without increasing the latency of the shift.
+ ;;
+ ;; We want to make sure and split up the operations for the scheduler since
+ ;; these instructions can (and should) schedule independently.
+ ;;
+ ;; It would be clearer if combine used the same operator for both expressions,
+ ;; it's somewhat confusing to have a mult in ine operation and an ashift
+ ;; in the other.
+ (define_insn ""
+   [(set (match_operand:SI 0 "register_operand" "=r")
+ 	(plus:SI (mult:SI (match_operand:SI 2 "register_operand" "r")
+ 			  (match_operand:SI 3 "shadd_operand" ""))
+ 		 (match_operand:SI 1 "register_operand" "r")))
+    (set (match_operand:SI 4 "register_operand" "=r")
+ 	(ashift:SI (match_dup 2)
+ 		   (match_operand:SI 5 "const_int_operand" "i")))]
+   "INTVAL (operands[5]) == exact_log2 (INTVAL (operands[3]))"
+   "#"
+   [(set_attr "type" "binary")
+    (set_attr "length" "8")])
+ 
+ (define_split
+   [(set (match_operand:SI 0 "register_operand" "=r")
+ 	(plus:SI (mult:SI (match_operand:SI 2 "register_operand" "r")
+ 			  (match_operand:SI 3 "shadd_operand" ""))
+ 		 (match_operand:SI 1 "register_operand" "r")))
+    (set (match_operand:SI 4 "register_operand" "=r")
+ 	(ashift:SI (match_dup 2)
+ 		   (match_operand:SI 5 "const_int_operand" "i")))]
+   "INTVAL (operands[5]) == exact_log2 (INTVAL (operands[3]))"
+   [(set (match_dup 4) (ashift:SI (match_dup 2) (match_dup 5)))
+    (set (match_dup 0) (plus:SI (mult:SI (match_dup 2) (match_dup 3))
+ 			       (match_dup 1)))]
+   "")
+ 
  ;; This variant of the above insn can occur if the first operand
  ;; is the frame pointer.  This is a kludge, but there doesn't
  ;; seem to be a way around it.  Only recognize it while reloading.