re PR target/49881 ([AVR] Inefficient stack manipulation around calls)

PR target/49881
        * config/avr/avr.h (PUSH_ROUNDING): New.
        * config/avr/avr.md (pushqi1): Rename from *pushqi.
        (*pushhi, *pushsi, *pushsf): Remove.
        (MPUSH): New mode iterator.
        (push<MPUSH>1): New expander.

From-SVN: r177071

gcc/ChangeLog

+2011-08-01  Richard Henderson  <rth@redhat.com>
+
+	PR target/49881
+	* config/avr/avr.h (PUSH_ROUNDING): New.
+	* config/avr/avr.md (pushqi1): Rename from *pushqi.
+	(*pushhi, *pushsi, *pushsf): Remove.
+	(MPUSH): New mode iterator.
+	(push<MPUSH>1): New expander.
+
 2011-08-01  Anatoly Sokolov  <aesok@post.ru>
 
 	* config/mmix/mmix.h (PREFERRED_RELOAD_CLASS,

gcc/config/avr/avr.h

@@ -685,3 +685,7 @@ struct GTY(()) machine_function
   /* 'true' if a callee might be tail called */
   int sibcall_fails;
 };
+
+/* AVR does not round pushes, but the existance of this macro is
+   required in order for pushes to be generated.  */
+#define PUSH_ROUNDING(X)	(X)

gcc/config/avr/avr.md

@@ -202,8 +202,7 @@
   DONE;
 })
 
-
-(define_insn "*pushqi"
+(define_insn "pushqi1"
   [(set (mem:QI (post_dec:HI (reg:HI REG_SP)))
         (match_operand:QI 0 "reg_or_0_operand" "r,L"))]
   ""
@@ -212,33 +211,29 @@
 	push __zero_reg__"
   [(set_attr "length" "1,1")])
 
-(define_insn "*pushhi"
-  [(set (mem:HI (post_dec:HI (reg:HI REG_SP)))
-        (match_operand:HI 0 "reg_or_0_operand" "r,L"))]
-  ""
-  "@
-	push %B0\;push %A0
-	push __zero_reg__\;push __zero_reg__"
-  [(set_attr "length" "2,2")])
+;; All modes for a multi-byte push.  We must include complex modes here too,
+;; lest emit_single_push_insn "helpfully " create the auto-inc itself.
+(define_mode_iterator MPUSH
+  [(CQI "")
+   (HI "") (CHI "")
+   (SI "") (CSI "")
+   (DI "") (CDI "")
+   (SF "") (SC "")])
 
-(define_insn "*pushsi"
-  [(set (mem:SI (post_dec:HI (reg:HI REG_SP)))
-        (match_operand:SI 0 "reg_or_0_operand" "r,L"))]
+(define_expand "push<mode>1"
+  [(match_operand:MPUSH 0 "general_operand" "")]
   ""
-  "@
-	push %D0\;push %C0\;push %B0\;push %A0
-	push __zero_reg__\;push __zero_reg__\;push __zero_reg__\;push __zero_reg__"
-  [(set_attr "length" "4,4")])
-
-(define_insn "*pushsf"
-  [(set (mem:SF (post_dec:HI (reg:HI REG_SP)))
-        (match_operand:SF 0 "register_operand" "r"))]
-  ""
-  "push %D0
-	push %C0
-	push %B0
-	push %A0"
-  [(set_attr "length" "4")])
+{
+  int i;
+  for (i = GET_MODE_SIZE (<MODE>mode) - 1; i >= 0; --i)
+    {
+      rtx part = simplify_gen_subreg (QImode, operands[0], <MODE>mode, i);
+      if (part != const0_rtx)
+	part = force_reg (QImode, part);
+      emit_insn (gen_pushqi1 (part));
+    }
+  DONE;
+})
 
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 ;; move byte