# HG changeset patch
# User Gilles Duboscq <gilles.duboscq@oracle.com>
# Date 1311760417 -7200
# Node ID e3d3fd5b638a7337415f2bf281390a1ebe4a06fa
# Parent  dcc79d5d0d82fd4159783cb8c69c57c97a9865c8
Canonicalize Negate(Negate(x)) for int/long remove incorrect canonicalization of FloatSub(0.0, x) to Negate(x)

diff -r dcc79d5d0d82 -r e3d3fd5b638a ProblemsIdeas.txt
--- a/ProblemsIdeas.txt	Wed Jul 27 10:33:03 2011 +0200
+++ b/ProblemsIdeas.txt	Wed Jul 27 11:53:37 2011 +0200
@@ -79,3 +79,7 @@
 
 * Rematerialize only the nodes that were affected by GVN
   This will probably require something that tracks changes to the Graph, the cost of such a tracking should be evaluated
+
+* Hints on register pressure
+
+  Sometimes we can make better decisions if we know the register pressure, it would be nice to have a way to know about it. Maybe we have register allocation on SSA we can somehow interact with it and try to lower the pressure in some areas on request?
diff -r dcc79d5d0d82 -r e3d3fd5b638a graal/com.oracle.max.graal.compiler/src/com/oracle/max/graal/compiler/ir/FloatSub.java
--- a/graal/com.oracle.max.graal.compiler/src/com/oracle/max/graal/compiler/ir/FloatSub.java	Wed Jul 27 10:33:03 2011 +0200
+++ b/graal/com.oracle.max.graal.compiler/src/com/oracle/max/graal/compiler/ir/FloatSub.java	Wed Jul 27 11:53:37 2011 +0200
@@ -92,20 +92,6 @@
                     }
                     return new FloatAdd(kind, x, Constant.forDouble(-c, graph), sub.isStrictFP(), graph);
                 }
-            } else if (x.isConstant()) {
-                // TODO (gd) check that Negate impl for floating point is really faster/better than 0.0 - x
-                if (kind == CiKind.Float) {
-                    float c = x.asConstant().asFloat();
-                    if (c == 0.0f) {
-                        return new Negate(y, graph);
-                    }
-                } else {
-                    assert kind == CiKind.Double;
-                    double c = x.asConstant().asDouble();
-                    if (c == 0.0) {
-                        return new Negate(y, graph);
-                    }
-                }
             }
             return sub;
         }
diff -r dcc79d5d0d82 -r e3d3fd5b638a graal/com.oracle.max.graal.compiler/src/com/oracle/max/graal/compiler/ir/Negate.java
--- a/graal/com.oracle.max.graal.compiler/src/com/oracle/max/graal/compiler/ir/Negate.java	Wed Jul 27 10:33:03 2011 +0200
+++ b/graal/com.oracle.max.graal.compiler/src/com/oracle/max/graal/compiler/ir/Negate.java	Wed Jul 27 11:53:37 2011 +0200
@@ -35,9 +35,8 @@
 public final class Negate extends FloatingNode {
     private static final NegateCanonicalizerOp CANONICALIZER = new NegateCanonicalizerOp();
 
-    private static final int INPUT_COUNT = 2;
+    private static final int INPUT_COUNT = 1;
     private static final int INPUT_X = 0;
-    private static final int INPUT_Y = 1;
 
     private static final int SUCCESSOR_COUNT = 0;
 
@@ -129,6 +128,9 @@
                     case Double: return Constant.forDouble(-x.asConstant().asDouble(), graph);
                 }
             }
+            if (x instanceof Negate && x.kind == CiKind.Int || x.kind == CiKind.Long) {
+                return ((Negate) x).x();
+            }
             return negate;
         }
     }