add a utility word vreg>constant

diff --git a/basis/compiler/cfg/value-numbering/graph/graph.factor b/basis/compiler/cfg/value-numbering/graph/graph.factor
index 7ec9eaf7ce1a4466891ce488070d05d67889a85f..41e72019533658d459f7bd8ecf5521b992738aa0 100644 (file)
--- a/basis/compiler/cfg/value-numbering/graph/graph.factor
+++ b/basis/compiler/cfg/value-numbering/graph/graph.factor
@@ -26,6 +26,8 @@ SYMBOL: vregs>vns
 
 : vn>constant ( vn -- constant ) vn>expr value>> ; inline
 
+: vreg>constant ( vreg -- constant ) vreg>vn vn>constant ; inline
+
 : init-value-graph ( -- )
     0 vn-counter set
     <bihash> exprs>vns set