# HG changeset patch
# User Christian Wimmer <christian.wimmer@oracle.com>
# Date 1351620755 25200
# Node ID c162fcf45ce79588e9f18efb7b65aaf09460d3a0
# Parent  ea38da80dd29b9f9bbf0eec34eaab8a7a9f56aa7
CodeCacheProvider.callKillsRegisters is not necessary because this information can be inferred from the register configuration

diff -r ea38da80dd29 -r c162fcf45ce7 graal/com.oracle.graal.api.code/src/com/oracle/graal/api/code/CodeCacheProvider.java
--- a/graal/com.oracle.graal.api.code/src/com/oracle/graal/api/code/CodeCacheProvider.java	Tue Oct 30 13:54:39 2012 +0100
+++ b/graal/com.oracle.graal.api.code/src/com/oracle/graal/api/code/CodeCacheProvider.java	Tue Oct 30 11:12:35 2012 -0700
@@ -70,12 +70,6 @@
     int getCustomStackAreaSize();
 
     /**
-     * Determines if a call instruction in compiled code can assume all allocatable
-     * registers are killed by the call.
-     */
-    boolean callKillsRegisters();
-
-    /**
      * Minimum size of the stack area reserved for outgoing parameters. This area is reserved in all cases, even when
      * the compiled method has no regular call instructions.
      *
diff -r ea38da80dd29 -r c162fcf45ce7 graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/alloc/LinearScanWalker.java
--- a/graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/alloc/LinearScanWalker.java	Tue Oct 30 13:54:39 2012 +0100
+++ b/graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/alloc/LinearScanWalker.java	Tue Oct 30 11:12:35 2012 -0700
@@ -29,7 +29,7 @@
 import java.util.*;
 
 import com.oracle.graal.api.code.*;
-import com.oracle.graal.api.code.Register.*;
+import com.oracle.graal.api.code.Register.RegisterFlag;
 import com.oracle.graal.api.meta.*;
 import com.oracle.graal.compiler.alloc.Interval.RegisterBinding;
 import com.oracle.graal.compiler.alloc.Interval.RegisterPriority;
@@ -37,7 +37,7 @@
 import com.oracle.graal.compiler.alloc.Interval.State;
 import com.oracle.graal.debug.*;
 import com.oracle.graal.lir.*;
-import com.oracle.graal.lir.StandardOp.*;
+import com.oracle.graal.lir.StandardOp.MoveOp;
 import com.oracle.graal.nodes.cfg.*;
 import com.oracle.graal.phases.*;
 import com.oracle.graal.phases.util.*;
@@ -73,7 +73,13 @@
 
     LinearScanWalker(LinearScan allocator, Interval unhandledFixedFirst, Interval unhandledAnyFirst) {
         super(allocator, unhandledFixedFirst, unhandledAnyFirst);
-        this.callKillsRegisters = allocator.frameMap.runtime.callKillsRegisters();
+
+        // If all allocatable registers are caller saved, then no registers are live across a call site.
+        // The register allocator can save time not trying to find a register at a call site.
+        HashSet<Register> registers = new HashSet<>(Arrays.asList(allocator.frameMap.registerConfig.getAllocatableRegisters()));
+        registers.removeAll(Arrays.asList(allocator.frameMap.registerConfig.getCallerSaveRegisters()));
+        callKillsRegisters = registers.size() == 0;
+
         moveResolver = new MoveResolver(allocator);
         spillIntervals = Util.uncheckedCast(new List[allocator.registers.length]);
         for (int i = 0; i < allocator.registers.length; i++) {
diff -r ea38da80dd29 -r c162fcf45ce7 graal/com.oracle.graal.hotspot.amd64/src/com/oracle/graal/hotspot/amd64/AMD64HotSpotRuntime.java
--- a/graal/com.oracle.graal.hotspot.amd64/src/com/oracle/graal/hotspot/amd64/AMD64HotSpotRuntime.java	Tue Oct 30 13:54:39 2012 +0100
+++ b/graal/com.oracle.graal.hotspot.amd64/src/com/oracle/graal/hotspot/amd64/AMD64HotSpotRuntime.java	Tue Oct 30 11:12:35 2012 -0700
@@ -123,11 +123,6 @@
     }
 
     @Override
-    public boolean callKillsRegisters() {
-        return true;
-    }
-
-    @Override
     public Register threadRegister() {
         return r15;
     }