Fix dead load/store elimination

TODO.FACTOR.txt

@@ -1,5 +1,7 @@
 should fix in 0.82:
 
+- constant branch folding
+- getenv, setenv, fast-slot stuff
 - 3 >n fep
 - amd64 %box-struct
 - get factor running on mac intel
@@ -27,6 +29,7 @@ should fix in 0.82:
 
 + ui/help:
 
+- polish OS X menu bar code
 - help search
 - reimplement clicking input
 - reimplement tab completion
@@ -74,7 +77,6 @@ should fix in 0.82:
 - the invalid recursion form case needs to be fixed, for inlines too
 - code gc
 - compiled gc check slows things down
-- fix branch folding
 
 + misc:
 

library/compiler/stack.factor

@@ -8,8 +8,8 @@ namespaces prettyprint sequences vectors words ;
     2dup length <= [
         cut-phantom
     ] [
-        [ phantom-locs ] keep [ length swap tail-slice ] keep
-        append
+        [ phantom-locs ] keep [ length swap head-slice* ] keep
+        [ append 0 ] keep set-length
     ] if ;
 
 : phantom-shuffle-inputs ( shuffle -- locs locs )
@@ -26,9 +26,9 @@ namespaces prettyprint sequences vectors words ;
     free-vregs get length <= ;
 
 : phantom-shuffle ( shuffle -- )
-    ! compute-free-vregs sufficient-shuffle-vregs? [
+    compute-free-vregs sufficient-shuffle-vregs? [
         end-basic-block compute-free-vregs
-    ! ] unless
+    ] unless
     [ phantom-shuffle-inputs ] keep
     [ shuffle* ] keep adjust-shuffle
     (template-outputs) ;

library/compiler/templates.factor

@@ -90,7 +90,7 @@ SYMBOL: phantom-r
 : lazy-load ( value loc -- value )
     over ds-loc? pick cs-loc? or [
         dupd = [
-            drop f
+            >r alloc-reg <vreg> dup r> %peek , ! drop f
         ] [
             >r alloc-reg <vreg> dup r> %peek ,
         ] if
@@ -166,11 +166,8 @@ SYMBOL: any-reg
     >r phantom-d get template-match? r> and ;
 
 : split-template ( template phantom -- slow fast )
-    over length over length <= [
-        drop { } swap
-    ] [
-        length swap cut*
-    ] if ;
+    over length over length <=
+    [ drop { } swap ] [ length swap cut* ] if ;
 
 : split-templates ( template template -- slow slow fast fast )
     >r phantom-d get split-template r>

library/test/compiler/templates.factor

@@ -14,6 +14,10 @@ math-internals namespaces test ;
 [ 0 ] [ 3 [ tag ] compile-1 ] unit-test
 [ 0 3 ] [ 3 [ [ tag ] keep ] compile-1 ] unit-test
 
+[ 2 3 ] [ 3 [ 2 swap ] compile-1 ] unit-test
+
+[ 2 3 4 ] [ 3 [ 2 swap 4 ] compile-1 ] unit-test
+
 [ { 1 2 3 } { 1 4 3 } 8 8 ]
 [ { 1 2 3 } { 1 4 3 } [ over type over type ] compile-1 ]
 unit-test