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changeset 21787:2766fee1809a

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Use the fact that a range checked array index is not negative to avoid sign-extension of the index register.
author Roland Schatz <roland.schatz@oracle.com>
date Mon, 08 Jun 2015 19:32:59 +0200
parents ae2a39857ab4
children c1610658bba0
files graal/com.oracle.graal.compiler.amd64/src/com/oracle/graal/compiler/amd64/AMD64AddressLowering.java graal/com.oracle.graal.replacements/src/com/oracle/graal/replacements/DefaultJavaLoweringProvider.java
diffstat 2 files changed, 50 insertions(+), 15 deletions(-) [+]
line wrap: on
line diff
--- a/graal/com.oracle.graal.compiler.amd64/src/com/oracle/graal/compiler/amd64/AMD64AddressLowering.java	Mon Jun 08 19:32:53 2015 +0200
+++ b/graal/com.oracle.graal.compiler.amd64/src/com/oracle/graal/compiler/amd64/AMD64AddressLowering.java	Mon Jun 08 19:32:59 2015 +0200
@@ -25,6 +25,7 @@
 
 import com.oracle.graal.asm.*;
 import com.oracle.graal.asm.amd64.AMD64Address.Scale;
+import com.oracle.graal.compiler.common.type.*;
 import com.oracle.graal.nodes.*;
 import com.oracle.graal.nodes.calc.*;
 import com.oracle.graal.nodes.memory.address.*;
@@ -56,13 +57,13 @@
     }
 
     protected boolean improve(AMD64AddressNode ret) {
-        ValueNode newBase = improveConstDisp(ret, ret.getBase(), 0);
+        ValueNode newBase = improveInput(ret, ret.getBase(), 0);
         if (newBase != ret.getBase()) {
             ret.setBase(newBase);
             return true;
         }
 
-        ValueNode newIdx = improveConstDisp(ret, ret.getIndex(), ret.getScale().log2);
+        ValueNode newIdx = improveInput(ret, ret.getIndex(), ret.getScale().log2);
         if (newIdx != ret.getIndex()) {
             ret.setIndex(newIdx);
             return true;
@@ -107,19 +108,31 @@
         return false;
     }
 
-    private ValueNode improveConstDisp(AMD64AddressNode address, ValueNode node, int shift) {
+    private ValueNode improveInput(AMD64AddressNode address, ValueNode node, int shift) {
         if (node == null) {
             return null;
         }
 
         if (node.isConstant()) {
             return improveConstDisp(address, node, node.asJavaConstant(), null, shift);
-        } else if (node instanceof AddNode) {
-            AddNode add = (AddNode) node;
-            if (add.getX().isConstant()) {
-                return improveConstDisp(address, node, add.getX().asJavaConstant(), add.getY(), shift);
-            } else if (add.getY().isConstant()) {
-                return improveConstDisp(address, node, add.getY().asJavaConstant(), add.getX(), shift);
+        } else {
+            if (node.stamp() instanceof IntegerStamp && ((IntegerStamp) node.stamp()).getBits() == 64) {
+                if (node instanceof ZeroExtendNode) {
+                    if (((ZeroExtendNode) node).getInputBits() == 32) {
+                        /*
+                         * We can just swallow a zero-extend from 32 bit to 64 bit because the upper
+                         * half of the register will always be zero.
+                         */
+                        return ((ZeroExtendNode) node).getValue();
+                    }
+                } else if (node instanceof AddNode) {
+                    AddNode add = (AddNode) node;
+                    if (add.getX().isConstant()) {
+                        return improveConstDisp(address, node, add.getX().asJavaConstant(), add.getY(), shift);
+                    } else if (add.getY().isConstant()) {
+                        return improveConstDisp(address, node, add.getY().asJavaConstant(), add.getX(), shift);
+                    }
+                }
             }
         }
 
--- a/graal/com.oracle.graal.replacements/src/com/oracle/graal/replacements/DefaultJavaLoweringProvider.java	Mon Jun 08 19:32:53 2015 +0200
+++ b/graal/com.oracle.graal.replacements/src/com/oracle/graal/replacements/DefaultJavaLoweringProvider.java	Mon Jun 08 19:32:59 2015 +0200
@@ -204,11 +204,19 @@
         Kind elementKind = loadIndexed.elementKind();
         Stamp loadStamp = loadStamp(loadIndexed.stamp(), elementKind);
 
-        AddressNode address = createArrayAddress(graph, loadIndexed.array(), elementKind, loadIndexed.index());
+        PiNode pi = getBoundsCheckedIndex(loadIndexed, tool);
+        ValueNode checkedIndex = pi;
+        if (checkedIndex == null) {
+            checkedIndex = loadIndexed.index();
+        }
+
+        AddressNode address = createArrayAddress(graph, loadIndexed.array(), elementKind, checkedIndex);
         ReadNode memoryRead = graph.add(new ReadNode(address, NamedLocationIdentity.getArrayLocation(elementKind), loadStamp, BarrierType.NONE));
         ValueNode readValue = implicitLoadConvert(graph, elementKind, memoryRead);
 
-        memoryRead.setGuard(createBoundsCheck(loadIndexed, tool));
+        if (pi != null) {
+            memoryRead.setGuard(pi.getGuard());
+        }
 
         loadIndexed.replaceAtUsages(readValue);
         graph.replaceFixed(loadIndexed, memoryRead);
@@ -216,7 +224,18 @@
 
     protected void lowerStoreIndexedNode(StoreIndexedNode storeIndexed, LoweringTool tool) {
         StructuredGraph graph = storeIndexed.graph();
-        GuardingNode boundsCheck = createBoundsCheck(storeIndexed, tool);
+
+        PiNode pi = getBoundsCheckedIndex(storeIndexed, tool);
+        ValueNode checkedIndex;
+        GuardingNode boundsCheck;
+        if (pi == null) {
+            checkedIndex = storeIndexed.index();
+            boundsCheck = null;
+        } else {
+            checkedIndex = pi;
+            boundsCheck = pi.getGuard();
+        }
+
         Kind elementKind = storeIndexed.elementKind();
 
         ValueNode value = storeIndexed.value();
@@ -241,7 +260,7 @@
             }
         }
 
-        AddressNode address = createArrayAddress(graph, array, elementKind, storeIndexed.index());
+        AddressNode address = createArrayAddress(graph, array, elementKind, checkedIndex);
         WriteNode memoryWrite = graph.add(new WriteNode(address, NamedLocationIdentity.getArrayLocation(elementKind), implicitStoreConvert(graph, elementKind, value),
                         arrayStoreBarrierType(storeIndexed.elementKind())));
         memoryWrite.setGuard(boundsCheck);
@@ -639,7 +658,7 @@
 
     protected abstract ValueNode createReadArrayComponentHub(StructuredGraph graph, ValueNode arrayHub, FixedNode anchor);
 
-    protected GuardingNode createBoundsCheck(AccessIndexedNode n, LoweringTool tool) {
+    protected PiNode getBoundsCheckedIndex(AccessIndexedNode n, LoweringTool tool) {
         StructuredGraph graph = n.graph();
         ValueNode array = n.array();
         ValueNode arrayLength = readArrayLength(array, tool.getConstantReflection());
@@ -663,7 +682,10 @@
             }
         }
 
-        return tool.createGuard(n, graph.unique(new IntegerBelowNode(n.index(), arrayLength)), BoundsCheckException, InvalidateReprofile);
+        GuardingNode guard = tool.createGuard(n, graph.unique(new IntegerBelowNode(n.index(), arrayLength)), BoundsCheckException, InvalidateReprofile);
+        IntegerStamp lengthStamp = (IntegerStamp) arrayLength.stamp();
+        IntegerStamp indexStamp = StampFactory.forInteger(32, 0, lengthStamp.upperBound());
+        return graph.unique(new PiNode(n.index(), indexStamp, guard.asNode()));
     }
 
     protected GuardingNode createNullCheck(ValueNode object, FixedNode before, LoweringTool tool) {