Cleanup of constant optimization

This commit cleans up constant optimization from the review of
https://github.com/scala/scala/pull/2214 .

* drops are done using the instruction's consumed count rather than a
  numeric literal
* drops are moved into one common method in the main instruction
  interpreter
* One instance of x.length > y.length is replaced with
  x.lengthCompare(y.length) > 0
* NaN is dealt with by treating it as an UNKNOWN
* A test is added to make sure NaN semantics aren't broken.
* The constant-optmization test is improved with tests for switch
  statements

1 files changed, 43 insertions, 0 deletions

diff --git a/test/files/run/constant-optimization.scala b/test/files/run/constant-optimization.scala
index 86f981e13f..5d13272f3b 100644
--- a/test/files/run/constant-optimization.scala
+++ b/test/files/run/constant-optimization.scala
@@ -13,6 +13,49 @@ object Test extends App {
     println(s"testOneReachable: $y")
   }
 
+  def testAllReachable() {
+    val i = util.Random.nextInt
+    val y = (i % 2) match {
+      case 0 => "good"
+      case 1 => "good"
+      case _ => "good"
+    }
+    println(s"testAllReachable: $y")
+  }
+
+  def testOneUnreachable() {
+    val i = util.Random.nextInt
+    val x = if (i % 2 == 0) {
+      1
+    } else {
+      2
+    }
+    val y = x match {
+      case 0 => "good"
+      case 1 => "good"
+      case _ => "good"
+    }
+    println(s"testOneUnreachable: $y")
+  }
+
+  def testDefaultUnreachable() {
+    val i = util.Random.nextInt
+    val x = if (i % 2 == 0) {
+      1
+    } else {
+      2
+    }
+    val y = x match {
+      case 1 => "good"
+      case 2 => "good"
+      case _ => "good"
+    }
+    println(s"testDefaultUnreachable: $y")
+  }
+
   testBothReachable()
   testOneReachable()
+  testAllReachable()
+  testOneUnreachable()
+  testDefaultUnreachable()
 }