improvement: In NIR codegen always use nir.Type.Unit for if return …

…type if one of branches is unit type (#3644)
scala-native · Jan 2, 2024 · fff2bf0 · fff2bf0
1 parent 115ed42
commit fff2bf0
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Showing 2 changed files with 10 additions and 2 deletions.
diff --git a/nscplugin/src/main/scala-2/scala/scalanative/nscplugin/NirGenExpr.scala b/nscplugin/src/main/scala-2/scala/scalanative/nscplugin/NirGenExpr.scala
@@ -212,7 +212,11 @@ trait NirGenExpr[G <: nsc.Global with Singleton] { self: NirGenPhase[G] =>
 
     def genIf(tree: If): nir.Val = {
       val If(cond, thenp, elsep) = tree
-      val retty = genType(tree.tpe)
+      def isUnitType(tpe: Type) =
+        defn.isUnitType(tpe) || tpe =:= defn.BoxedUnitTpe
+      val retty =
+        if (isUnitType(thenp.tpe) || isUnitType(elsep.tpe)) nir.Type.Unit
+        else genType(tree.tpe)
       genIf(retty, cond, thenp, elsep)(tree.pos)
     }
 

diff --git a/nscplugin/src/main/scala-3/scala/scalanative/nscplugin/NirGenExpr.scala b/nscplugin/src/main/scala-3/scala/scalanative/nscplugin/NirGenExpr.scala
@@ -451,7 +451,11 @@ trait NirGenExpr(using Context) {
     def genIf(tree: If): nir.Val = {
       given nir.Position = tree.span
       val If(cond, thenp, elsep) = tree
-      val retty = genType(tree.tpe)
+      def isUnitType(tpe: Type) =
+        tpe =:= defn.UnitType || defn.isBoxedUnitClass(tpe.sym)
+      val retty =
+        if (isUnitType(thenp.tpe) || isUnitType(elsep.tpe)) nir.Type.Unit
+        else genType(tree.tpe)
       genIf(retty, cond, thenp, elsep)
     }