Implemented compare/signum intrinsics as HCompare
(with all code generation for all)

Rationale:
At HIR level, many more optimizations are possible, while ultimately
generated code can take advantage of full semantics.

Change-Id: I6e2ee0311784e5e336847346f7f3c4faef4fd17e
diff --git a/test/567-checker-compare/src/Main.java b/test/567-checker-compare/src/Main.java
index 52abb75..951d2c7 100644
--- a/test/567-checker-compare/src/Main.java
+++ b/test/567-checker-compare/src/Main.java
@@ -88,6 +88,10 @@
     expectEquals(1, compare64(Long.MAX_VALUE, 1L));
     expectEquals(1, compare64(Long.MAX_VALUE, Long.MAX_VALUE - 1L));
 
+    expectEquals(-1, compare64(0x111111117FFFFFFFL, 0x11111111FFFFFFFFL));
+    expectEquals(0, compare64(0x111111117FFFFFFFL, 0x111111117FFFFFFFL));
+    expectEquals(1, compare64(0x11111111FFFFFFFFL, 0x111111117FFFFFFFL));
+
     for (long i = -11L; i <= 11L; i++) {
       for (long j = -11L; j <= 11L; j++) {
         int expected = 0;
@@ -97,6 +101,14 @@
       }
     }
 
+    for (long i = Long.MIN_VALUE; i <= Long.MIN_VALUE + 11L; i++) {
+      expectEquals(-1, compare64(i, 0));
+    }
+
+    for (long i = Long.MAX_VALUE; i >= Long.MAX_VALUE - 11L; i--) {
+      expectEquals(1, compare64(i, 0));
+    }
+
     System.out.println("passed");
   }