re PR middle-end/27663 (missed-optimization transforming a byte array to unsigned long)

	PR target/27663
	PR target/41076
	* config/avr/predicates.md (const_8_16_24_operand): New predicate.
	* config/avr/avr.md ("*ior<mode>qi.byte0",
	"*ior<mode>qi.byte1-3"): New define_insn_and_split patterns.

From-SVN: r173792

gcc/ChangeLog

 2011-05-16  Georg-Johann Lay  <avr@gjlay.de>
 
+	PR target/27663
+	PR target/41076
+	* config/avr/predicates.md (const_8_16_24_operand): New predicate.
+	* config/avr/avr.md ("*ior<mode>qi.byte0",
+	"*ior<mode>qi.byte1-3"): New define_insn_and_split patterns.
+
+2011-05-16  Georg-Johann Lay  <avr@gjlay.de>
+
 	PR target/45099
 	* config/avr/avr.c (avr_function_arg_advance): Error if a fixed
 	register is needed for a function argument.

gcc/config/avr/avr.md

@@ -3388,3 +3388,42 @@
 	clr __zero_reg__"
   [(set_attr "length" "3")
    (set_attr "cc" "clobber")])
+
+
+;; Some combine patterns that try to fix bad code when a value is composed
+;; from byte parts like in PR27663.
+;; The patterns give some release but the code still is not optimal,
+;; in particular when subreg lowering (-fsplit-wide-types) is turned on.
+;; That switch obfuscates things here and in many other places.
+
+(define_insn_and_split "*ior<mode>qi.byte0"
+  [(set (match_operand:HISI 0 "register_operand"                 "=r")
+        (ior:HISI
+         (zero_extend:HISI (match_operand:QI 1 "register_operand" "r"))
+         (match_operand:HISI 2 "register_operand"                 "0")))]
+  ""
+  "#"
+  "reload_completed"
+  [(set (match_dup 3)
+        (ior:QI (match_dup 3)
+                (match_dup 1)))]
+  {
+    operands[3] = simplify_gen_subreg (QImode, operands[0], <MODE>mode, 0);
+  })
+
+(define_insn_and_split "*ior<mode>qi.byte1-3"
+  [(set (match_operand:HISI 0 "register_operand"                              "=r")
+        (ior:HISI
+         (ashift:HISI (zero_extend:HISI (match_operand:QI 1 "register_operand" "r"))
+                      (match_operand:QI 2 "const_8_16_24_operand"              "n"))
+         (match_operand:HISI 3 "register_operand"                              "0")))]
+  "INTVAL(operands[2]) < GET_MODE_BITSIZE (<MODE>mode)"
+  "#"
+  "&& reload_completed"
+  [(set (match_dup 4)
+        (ior:QI (match_dup 4)
+                (match_dup 1)))]
+  {
+    int byteno = INTVAL(operands[2]) / BITS_PER_UNIT;
+    operands[4] = simplify_gen_subreg (QImode, operands[0], <MODE>mode, byteno);
+  })

gcc/config/avr/predicates.md

@@ -138,3 +138,10 @@
 (define_predicate "pseudo_register_operand"
   (and (match_code "reg")
        (match_test "!HARD_REGISTER_P (op)")))
+
+;; Return true if OP is a constant integer that is either
+;; 8 or 16 or 24.
+(define_predicate "const_8_16_24_operand"
+  (and (match_code "const_int")
+       (match_test "8 == INTVAL(op) || 16 == INTVAL(op) || 24 == INTVAL(op)")))
+