PDP-11: expensive (in terms of backend binary size) optimizations:

src/cowbe/regcache.coh

@@ -161,3 +161,38 @@ sub RegCacheFindValue(sym: [Symbol], off: Size): (reg: RegId) is
 	end loop;
 end sub;
 
+sub RegCacheCopy(src: RegId, dst: RegId) is
+	var p := &register_cache[0];
+	while p != &register_cache[@sizeof register_cache] loop
+		if (p.state != CACHE_SLOT_EMPTY) and ((src & p.reg) != 0) then
+			p.reg := p.reg | dst;
+		end if;
+		p := @next p;
+	end loop;
+end sub;
+
+sub RegCacheGet(src: RegId): (q: [CacheSlot]) is
+	var p := &register_cache[0];
+	q := nil;
+	while p != &register_cache[@sizeof register_cache] loop
+		if (p.state != CACHE_SLOT_EMPTY) and ((src & p.reg) != 0) then
+			q := p;
+			return;
+		end if;
+		p := @next p;
+	end loop;
+end sub;
+
+sub RegCacheFind(state: uint8, subr: [Subroutine], wsid: uint8, off: Size): (reg: RegId) is
+	var p := &register_cache[0];
+	reg := 0;
+	while p != &register_cache[@sizeof register_cache] loop
+		if (p.state == state) and (p.subr == subr)
+				and (p.wsid == wsid) and (p.number == (off as Word)) then
+			reg := p.reg;
+			return;
+		end if;
+		p := @next p;
+	end loop;
+end sub;
+

tests/pointers.good

@@ -3,3 +3,4 @@
 p.byte==4: yes
 direct: yes
 indirect: yes
+minus1: yes

tests/pointers.test.cow

@@ -31,6 +31,9 @@ sub IndexTest() is
 
 	var p := &b;
 	print("indirect"); if p.buffer[p.offset] == 42 then yes(); else no(); end if;
+
+	var pb := &b.buffer[3];
+	print("minus1"); if [pb - 1] == 42 then yes(); else no(); end if;
 end sub;
 IndexTest();
 

tests/regcache.good

@@ -3,3 +3,6 @@ regcache1 sub: yes
 regcache1 or: yes
 regcache1 xor: yes
 regcache1 and: yes
+regcache1 shl: yes
+regcache1 shr: yes
+regcache2: yes

tests/regcache.test.cow

@@ -27,5 +27,28 @@ sub cache1() is
     c := a & b;
     d := a;
     print("regcache1 and"); if c == 0 and d == 2 then yes(); else no(); end if;
+
+    c := a << b;
+    d := a;
+    print("regcache1 shl"); if c == 4 and d == 2 then yes(); else no(); end if;
+
+    c := a >> b;
+    d := a;
+    print("regcache1 shr"); if c == 1 and d == 2 then yes(); else no(); end if;
 end sub;
 cache1();
+
+# STORE should flush cached pointer value
+sub cache2() is
+    var c: uint8;
+    var d: uint8;
+    var p: [uint8] := "ab";
+
+    c := [p];
+    p := p + 1;
+    d := [p];
+
+    print("regcache2"); if c == 'a' and d == 'b' then yes(); else no(); end if;
+end sub;
+cache2();
+

tests/shifts-16bit.good

@@ -5,6 +5,7 @@ bug1<<8 == 0x8800: yes
 big>>zero == 0x8000: yes
 big>>one == 0x4000: yes
 big>>two == 0x2000: yes
+bug1>>14 == 0x3: yes
 bug1>>10 == 0x30: yes
 bug1>>8 == 0xc3: yes
 mbig>>zero == 0x8000: yes

tests/shifts-16bit.test.cow

@@ -23,6 +23,7 @@ sub rshiftu() is
 	print("big>>zero == 0x8000"); if big>>zero == 0x8000 then yes(); else no(); end if;
 	print("big>>one == 0x4000");  if big>>one == 0x4000 then yes(); else no(); end if;
 	print("big>>two == 0x2000");  if big>>two == 0x2000 then yes(); else no(); end if;
+	print("bug1>>14 == 0x3") ;    if bug1>>14 == 0x3 then yes(); else no(); end if;
 	print("bug1>>10 == 0x30");    if bug1>>10 == 0x30 then yes(); else no(); end if;
 	print("bug1>>8 == 0xc3");     if bug1>>8 == 0xc3 then yes(); else no(); end if;
 end sub;

tests/shifts-8bit.good

@@ -1,10 +1,18 @@
 one<<zero == 1: yes
 one<<one == 2: yes
 one<<two == 4: yes
+one<<ONE == 2: yes
+one<<TWO == 4: yes
 onetwoeight<<one == 0: yes
+onetwoeight<<ONE == 0: yes
+onetwoeight<<NINE == 0: yes
 onetwoeight>>zero == 128: yes
 onetwoeight>>one == 64: yes
 onetwoeight>>two == 32: yes
+onetwoeight>>ONE == 64: yes
+onetwoeight>>TWO == 32: yes
 mbig>>zero == 0x80: yes
 mbig>>one == 0xc0: yes
 mbig>>two == 0xe0: yes
+mbig>>ONE == 0xc0: yes
+mbig>>TWO == 0xe0: yes

tests/shifts-8bit.test.cow

@@ -7,25 +7,37 @@ var one: uint8 := 1;
 var two: uint8 := 2;
 var onetwoeight: uint8 := 0x80;
 
+const ONE := 1;
+const TWO := 2;
+const NINE := 9;
+
 sub lshift() is
 	print("one<<zero == 1"); if one<<zero == 1 then yes(); else no(); end if;
 	print("one<<one == 2"); if one<<one == 2 then yes(); else no(); end if;
 	print("one<<two == 4"); if one<<two == 4 then yes(); else no(); end if;
+	print("one<<ONE == 2"); if one<<ONE == 2 then yes(); else no(); end if;
+	print("one<<TWO == 4"); if one<<TWO == 4 then yes(); else no(); end if;
 	print("onetwoeight<<one == 0"); if onetwoeight<<one == 0 then yes(); else no(); end if;
+	print("onetwoeight<<ONE == 0"); if onetwoeight<<ONE == 0 then yes(); else no(); end if;
+	print("onetwoeight<<NINE == 0"); if onetwoeight<<NINE == 0 then yes(); else no(); end if;
 end sub;
 lshift();
 
 sub rshiftu() is
 	print("onetwoeight>>zero == 128"); if onetwoeight>>zero == 128 then yes(); else no(); end if;
 	print("onetwoeight>>one == 64"); if onetwoeight>>one == 64 then yes(); else no(); end if;
 	print("onetwoeight>>two == 32"); if onetwoeight>>two == 32 then yes(); else no(); end if;
+	print("onetwoeight>>ONE == 64"); if onetwoeight>>ONE == 64 then yes(); else no(); end if;
+	print("onetwoeight>>TWO == 32"); if onetwoeight>>TWO == 32 then yes(); else no(); end if;
 end sub;
 rshiftu();
 
 sub rshifts() is
 	print("mbig>>zero == 0x80"); if mbig>>zero == 0x80 then yes(); else no(); end if;
 	print("mbig>>one == 0xc0"); if mbig>>one == 0xc0 then yes(); else no(); end if;
 	print("mbig>>two == 0xe0"); if mbig>>two == 0xe0 then yes(); else no(); end if;
+	print("mbig>>ONE == 0xc0"); if mbig>>ONE == 0xc0 then yes(); else no(); end if;
+	print("mbig>>TWO == 0xe0"); if mbig>>TWO == 0xe0 then yes(); else no(); end if;
 end sub;
 rshifts();