# HG changeset patch
# User Roland Schatz <roland.schatz@oracle.com>
# Date 1431510797 -7200
# Node ID c4b87ad2c4c8b553be64508e15416884c517e039
# Parent  19801a65cf571ded902306e64f74d25b88006a3d
Improve code generation for zero extend on AMD64.

diff -r 19801a65cf57 -r c4b87ad2c4c8 graal/com.oracle.graal.compiler.amd64/src/com/oracle/graal/compiler/amd64/AMD64LIRGenerator.java
--- a/graal/com.oracle.graal.compiler.amd64/src/com/oracle/graal/compiler/amd64/AMD64LIRGenerator.java	Tue May 12 18:26:52 2015 -0700
+++ b/graal/com.oracle.graal.compiler.amd64/src/com/oracle/graal/compiler/amd64/AMD64LIRGenerator.java	Wed May 13 11:53:17 2015 +0200
@@ -1066,16 +1066,36 @@
             return result;
         } else {
             assert inputVal.getKind().getStackKind() == Kind.Int;
-            Variable result = newVariable(LIRKind.derive(inputVal).changeType(Kind.Int));
-            int mask = (int) CodeUtil.mask(fromBits);
-            append(new AMD64Binary.DataOp(AND.getRMOpcode(DWORD), DWORD, result, asAllocatable(inputVal), JavaConstant.forInt(mask)));
+
+            LIRKind resultKind = LIRKind.derive(inputVal);
+            OperandSize resultSize;
             if (toBits > 32) {
-                Variable longResult = newVariable(LIRKind.derive(inputVal).changeType(Kind.Long));
-                emitMove(longResult, result);
-                return longResult;
+                resultKind = resultKind.changeType(Kind.Long);
+                resultSize = QWORD;
             } else {
-                return result;
+                resultKind = resultKind.changeType(Kind.Int);
+                resultSize = DWORD;
+            }
+
+            switch (fromBits) {
+                case 8:
+                    return emitConvertOp(resultKind, MOVZXB, resultSize, inputVal);
+                case 16:
+                    return emitConvertOp(resultKind, MOVZX, resultSize, inputVal);
+                case 32:
+                    return emitConvertOp(resultKind, MOV, DWORD, inputVal);
             }
+
+            // odd bit count, fall back on manual masking
+            Variable result = newVariable(resultKind);
+            JavaConstant mask;
+            if (toBits > 32) {
+                mask = JavaConstant.forLong(CodeUtil.mask(fromBits));
+            } else {
+                mask = JavaConstant.forInt((int) CodeUtil.mask(fromBits));
+            }
+            append(new AMD64Binary.DataOp(AND.getRMOpcode(DWORD), DWORD, result, asAllocatable(inputVal), mask));
+            return result;
         }
     }