[GR-58077] Avoid r12 as null during LIR optizmiations.

PullRequest: graal/18803

Author: mur47x111

compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/hotspot/amd64/AMD64HotSpotLIRGenerator.java

@@ -96,15 +96,13 @@
 import jdk.vm.ci.code.RegisterConfig;
 import jdk.vm.ci.code.RegisterValue;
 import jdk.vm.ci.meta.AllocatableValue;
-import jdk.vm.ci.meta.Constant;
 import jdk.vm.ci.meta.DeoptimizationAction;
 import jdk.vm.ci.meta.DeoptimizationReason;
 import jdk.vm.ci.meta.JavaConstant;
 import jdk.vm.ci.meta.JavaKind;
 import jdk.vm.ci.meta.PlatformKind;
 import jdk.vm.ci.meta.SpeculationLog;
 import jdk.vm.ci.meta.Value;
-import jdk.vm.ci.meta.ValueKind;
 
 /**
  * LIR generator specialized for AMD64 HotSpot.
@@ -657,15 +655,4 @@ public int getArrayLengthOffset() {
     public Register getHeapBaseRegister() {
         return getProviders().getRegisters().getHeapBaseRegister();
     }
-
-    @Override
-    public AllocatableValue emitLoadConstant(ValueKind<?> kind, Constant constant) {
-        if (((AMD64Kind) kind.getPlatformKind()).isInteger() && constant instanceof JavaConstant && constant.isDefaultForKind()) {
-            Register zeroValueRegister = getProviders().getRegisters().getZeroValueRegister(config);
-            if (!Register.None.equals(zeroValueRegister)) {
-                return zeroValueRegister.asValue(kind);
-            }
-        }
-        return super.emitLoadConstant(kind, constant);
-    }
 }