Improved zero-check elimination for Shark

[Gary Benson]

Hi all,

This patch marks a couple of things we know are non-zero,
allowing the zero-check eliminator to work its magic.

Cheers,
Gary

-- 
http://gbenson.net/
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diff -r fd98e848b25c ChangeLog
--- a/ChangeLog	Fri Feb 27 04:08:04 2009 -0500
+++ b/ChangeLog	Fri Feb 27 14:52:46 2009 +0000
@@ -1,3 +1,14 @@
+2009-02-27  Gary Benson  <gbenson at redhat.com>
+
+	* ports/hotspot/src/share/vm/shark/sharkState.cpp
+	(SharkEntryState::initialize): Mark the receiver as
+	zero-checked for non-static methods.
+
+	* ports/hotspot/src/share/vm/shark/sharkValue.hpp
+	(SharkValue::jint_constant): Mark non-zero constants
+	as zero-checked.
+	(SharkValue::jlong_constant): Likewise.
+
 2009-02-27  Gary Benson  <gbenson at redhat.com>
 
 	* ports/hotspot/src/share/vm/shark/sharkBlock.cpp
diff -r fd98e848b25c ports/hotspot/src/share/vm/shark/sharkState.cpp
--- a/ports/hotspot/src/share/vm/shark/sharkState.cpp	Fri Feb 27 04:08:04 2009 -0500
+++ b/ports/hotspot/src/share/vm/shark/sharkState.cpp	Fri Feb 27 14:52:46 2009 +0000
@@ -94,6 +94,12 @@
     set_local(i, value);
   }
 
+  // Non-static methods have a guaranteed non-null receiver
+  if (!function()->target()->is_static()) {
+    assert(local(0)->is_jobject(), "should be");
+    local(0)->set_zero_checked(true);
+  }
+
   // Expression stack
   assert(!stack_depth_at_entry(), "entry block shouldn't have stack");
 }
diff -r fd98e848b25c ports/hotspot/src/share/vm/shark/sharkValue.hpp
--- a/ports/hotspot/src/share/vm/shark/sharkValue.hpp	Fri Feb 27 04:08:04 2009 -0500
+++ b/ports/hotspot/src/share/vm/shark/sharkValue.hpp	Fri Feb 27 14:52:46 2009 +0000
@@ -149,11 +149,17 @@
  public:
   static SharkValue* jint_constant(jint value)
   {
-    return create_jint(LLVMValue::jint_constant(value));
+    SharkValue *result = create_jint(LLVMValue::jint_constant(value));
+    if (value != 0)
+      result->set_zero_checked(true);
+    return result;
   }
   static SharkValue* jlong_constant(jlong value)
   {
-    return create_jlong(LLVMValue::jlong_constant(value));
+    SharkValue *result = create_jlong(LLVMValue::jlong_constant(value));
+    if (value != 0)
+      result->set_zero_checked(true);
+    return result;
   }
   static SharkValue* jfloat_constant(jfloat value)
   {