Merge pull request #185 from shattered/_01ed167f

Another round of cheap optimizations.

Author: davidgiven

src/cowbe/arch68000.cow.ng

@@ -415,20 +415,24 @@ gen RETURN() uses all
 
 // --- Miscellaneous --------------------------------------------------------
 
-gen dreg|any|any := CONSTANT():c
+gen dreg|any := CONSTANT():c
 {
 	var r := RegCacheFindConstant($c.value as uint32);
 	if r != 0 then
 		if (r & $$) != 0 then
 			return;
 		end if;
-		r := FindFirst(r);
 		E_insn("move.l");
-		E_reg(r);
+		E_reg(FindFirst(r));
 	else
-		E_insn("move.l");
-		E_const();
-		E_i32($c.value);
+		if $c.value == 0 then
+			E_insn("sub.l");
+			E_reg($$);
+		else
+			E_insn("move.l");
+			E_const();
+			E_i32($c.value);
+		end if;
 	end if;
 	E_comma();
 	E_reg($$);
@@ -445,9 +449,8 @@ gen areg := ADDRESS():a
 		if (r & $$) != 0 then
 			return;
 		end if;
-		r := FindFirst(r);
 		E_insn("move.l");
-		E_reg(r);
+		E_reg(FindFirst(r));
 	else
 		E_insn("lea");
 		E_openp();
@@ -617,13 +620,12 @@ gen imm := CONSTANT():c cost 5
 			if (r & dest) != 0 then
 				return;
 			end if;
-			r := FindFirst(r);
 			E_insn("move.l");
-			E_reg(r);
+			E_reg(FindFirst(r));
 			E_comma();
 			E_reg(dest);
 		else
-			RegCacheFlushValues();
+			RegCacheFlushValue(sym, off);
 
 			E_insn(insn);
 			E_openp();

src/cowbe/archpdp11.cow.ng

@@ -142,12 +142,8 @@
 	end sub;
 
 	sub E_push4(src: RegId) is
-		E_insn16("MOV");
-		E_reg(loreg(src));
-		E(", -(SP)\n");
-		E_insn16("MOV");
-		E_reg(hireg(src));
-		E(", -(SP)\n");
+		E_push(loreg(src));
+		E_push(hireg(src));
 	end sub;
 
 	sub E_pop(dest: RegId) is
@@ -158,13 +154,8 @@
 	end sub;
 
 	sub E_pop4(dest: RegId) is
-		R_flush(dest);
-		E("\tMOV\t(SP)+, ");
-		E_reg(hireg(dest));
-		E_nl();
-		E("\tMOV\t(SP)+, ");
-		E_reg(loreg(dest));
-		E_nl();
+		E_pop(hireg(dest));
+		E_pop(loreg(dest));
 	end sub;
 
 	sub E_mov(reg: RegId) is
@@ -606,7 +597,7 @@
 			E_u8(value);
 			E_comma();
 		else
-			E_insn16("asl");
+			E_insn("asl", reg);
 		end if;
 		E_reg(reg);
 		E_nl();
@@ -686,8 +677,7 @@
 			E_nl();
 			value := value - 8;
 		end if;
-		var v := value as uint8;
-		if v > 0 then
+		if value > 0 then
 			while value > 0 loop
 				E_insn16("CLC");
 				E_nl();

src/cowbe/archz80.cow.ng

@@ -649,8 +649,7 @@
 			return;
 		elseif cache != 0 then
 			# The value is already in a register, but not this one.
-			cache := FindFirst(cache);
-			ArchEmitMove(cache, reg);
+			ArchEmitMove(FindFirst(cache), reg);
 			return;
 		end if;