SI-7852 Omit null check for SomeModule.==

For the same reasons outlined in the previous commits.

1 files changed, 7 insertions, 2 deletions

diff --git a/src/compiler/scala/tools/nsc/backend/icode/GenICode.scala b/src/compiler/scala/tools/nsc/backend/icode/GenICode.scala
index 1413add240..a80fee876e 100644
--- a/src/compiler/scala/tools/nsc/backend/icode/GenICode.scala
+++ b/src/compiler/scala/tools/nsc/backend/icode/GenICode.scala
@@ -1320,6 +1320,7 @@ abstract class GenICode extends SubComponent  {
      */
     def isNull(t: Tree) = cond(t) { case Literal(Constant(null)) => true }
     def isLiteral(t: Tree) = cond(t) { case Literal(_) => true }
+    def isNonNullExpr(t: Tree) = isLiteral(t) || ((t.symbol ne null) && t.symbol.isModule)
 
     /* If l or r is constant null, returns the other ; otherwise null */
     def ifOneIsNull(l: Tree, r: Tree) = if (isNull(l)) r else if (isNull(r)) l else null
@@ -1515,8 +1516,12 @@ abstract class GenICode extends SubComponent  {
           val branchesReachable = !ctx1.bb.ignore
           ctx1.bb emitOnly CZJUMP(thenCtx.bb, elseCtx.bb, EQ, ObjectReference)
           branchesReachable
-        } else if (isLiteral(l)) {
-          // "" == expr -> "".equals(expr) (no null check)
+        } else if (isNonNullExpr(l)) {
+          // Avoid null check if L is statically non-null.
+          //
+          // "" == expr -> "".equals(expr)
+          // Nil == expr -> Nil.equals(expr)
+          //
           // Common enough (through pattern matching) to treat this specially here rather than
           // hoping that -Yconst-opt is enabled. The impossible branches for null checks lead
           // to spurious "branch not covered" warnings in Jacoco code coverage.