Mercurial > hg > graal-compiler

changeset 13352:cd22c6bb4a35

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use test instead of mov for poll
author Tom Rodriguez <tom.rodriguez@oracle.com>
date Mon, 16 Dec 2013 12:10:10 -0800
parents 7345e9672dc3
children 0e5c4f9fa9a5
files graal/com.oracle.graal.hotspot.amd64/src/com/oracle/graal/hotspot/amd64/AMD64HotSpotSafepointOp.java
diffstat 1 files changed, 10 insertions(+), 6 deletions(-) [+]
line wrap: on
line diff
--- a/graal/com.oracle.graal.hotspot.amd64/src/com/oracle/graal/hotspot/amd64/AMD64HotSpotSafepointOp.java	Mon Dec 16 10:22:17 2013 -0800
+++ b/graal/com.oracle.graal.hotspot.amd64/src/com/oracle/graal/hotspot/amd64/AMD64HotSpotSafepointOp.java	Mon Dec 16 12:10:10 2013 -0800
@@ -42,20 +42,24 @@
 public class AMD64HotSpotSafepointOp extends AMD64LIRInstruction {
 
     @State protected LIRFrameState state;
-    @Temp({OperandFlag.REG}) private AllocatableValue temp;
+    @Temp({OperandFlag.REG, OperandFlag.ILLEGAL}) private AllocatableValue temp;
 
     private final HotSpotVMConfig config;
 
     public AMD64HotSpotSafepointOp(LIRFrameState state, HotSpotVMConfig config, LIRGeneratorTool tool) {
         this.state = state;
         this.config = config;
-        temp = tool.newVariable(tool.target().wordKind);
+        if (isPollingPageFar(config)) {
+            temp = tool.newVariable(tool.target().wordKind);
+        } else {
+            // Don't waste a register if it's unneeded
+            temp = Value.ILLEGAL;
+        }
     }
 
     @Override
     public void emitCode(CompilationResultBuilder crb, AMD64MacroAssembler asm) {
-        RegisterValue scratch = (RegisterValue) temp;
-        emitCode(crb, asm, config, false, state, scratch.getRegister());
+        emitCode(crb, asm, config, false, state, temp instanceof RegisterValue ? ((RegisterValue) temp).getRegister() : null);
     }
 
     /**
@@ -76,7 +80,7 @@
             if (state != null) {
                 crb.recordInfopoint(pos, state, InfopointReason.SAFEPOINT);
             }
-            asm.movq(scratch, new AMD64Address(scratch));
+            asm.testl(rax, new AMD64Address(scratch));
         } else {
             crb.recordMark(atReturn ? MARK_POLL_RETURN_NEAR : MARK_POLL_NEAR);
             if (state != null) {
@@ -84,7 +88,7 @@
             }
             // The C++ code transforms the polling page offset into an RIP displacement
             // to the real address at that offset in the polling page.
-            asm.movq(scratch, new AMD64Address(rip, 0));
+            asm.testl(rax, new AMD64Address(rip, 0));
         }
     }
 }