# HG changeset patch
# User twisti
# Date 1387331896 28800
# Node ID af10ee69a8ac5d8ce976e37b605bce61a9af7220
# Parent  4db09b7304da2501cda023be6f7b542077f77076
fixed JDK-7079626: x64 emits unnecessary REX prefix

diff -r 4db09b7304da -r af10ee69a8ac graal/com.oracle.graal.asm.amd64/src/com/oracle/graal/asm/amd64/AMD64Assembler.java
--- a/graal/com.oracle.graal.asm.amd64/src/com/oracle/graal/asm/amd64/AMD64Assembler.java	Tue Dec 17 22:37:03 2013 +0100
+++ b/graal/com.oracle.graal.asm.amd64/src/com/oracle/graal/asm/amd64/AMD64Assembler.java	Tue Dec 17 17:58:16 2013 -0800
@@ -917,7 +917,7 @@
 
     public final void movb(AMD64Address dst, Register src) {
         assert src.getRegisterCategory() == AMD64.CPU : "must have byte register";
-        prefix(dst, src); // , true)
+        prefix(dst, src, true);
         emitByte(0x88);
         emitOperandHelper(src, dst);
     }
@@ -1895,6 +1895,10 @@
     }
 
     private void prefix(AMD64Address adr, Register reg) {
+        prefix(adr, reg, false);
+    }
+
+    private void prefix(AMD64Address adr, Register reg, boolean byteinst) {
         if (reg.encoding < 8) {
             if (needsRex(adr.getBase())) {
                 if (needsRex(adr.getIndex())) {
@@ -1905,7 +1909,7 @@
             } else {
                 if (needsRex(adr.getIndex())) {
                     emitByte(Prefix.REXX);
-                } else if (reg.encoding >= 4) {
+                } else if (byteinst && reg.encoding >= 4) {
                     emitByte(Prefix.REX);
                 }
             }