8256479: [PPC64] C2 crashes when UseVectorByteReverseInstructionsPPC64 used without SuperwordUseVSX

Reviewed-by: goetz, psandoz

Author: TheRealMDoerr

src/hotspot/cpu/ppc/vm_version_ppc.cpp

@@ -136,8 +136,13 @@ void VM_Version::initialize() {
     if (FLAG_IS_DEFAULT(UseCharacterCompareIntrinsics)) {
       FLAG_SET_ERGO(UseCharacterCompareIntrinsics, true);
     }
-    if (FLAG_IS_DEFAULT(UseVectorByteReverseInstructionsPPC64)) {
-      FLAG_SET_ERGO(UseVectorByteReverseInstructionsPPC64, true);
+    if (SuperwordUseVSX) {
+      if (FLAG_IS_DEFAULT(UseVectorByteReverseInstructionsPPC64)) {
+        FLAG_SET_ERGO(UseVectorByteReverseInstructionsPPC64, true);
+      }
+    } else if (UseVectorByteReverseInstructionsPPC64) {
+      warning("UseVectorByteReverseInstructionsPPC64 specified, but needs SuperwordUseVSX.");
+      FLAG_SET_DEFAULT(UseVectorByteReverseInstructionsPPC64, false);
     }
     if (FLAG_IS_DEFAULT(UseBASE64Intrinsics)) {
       FLAG_SET_ERGO(UseBASE64Intrinsics, true);

test/jdk/jdk/incubator/vector/Vector64ConversionTests.java

@@ -39,6 +39,17 @@
  *      Vector64ConversionTests
  */
 
+/*
+ * @test VectorConversionPPC64
+ * @bug 8256479
+ * @requires os.arch =="ppc64" | os.arch == "ppc64le"
+ * @summary VectorConversion on PPC64 without Vector Register usage
+ * @modules jdk.incubator.vector
+ * @modules java.base/jdk.internal.vm.annotation
+ * @run testng/othervm  -XX:-SuperwordUseVSX -XX:-TieredCompilation --add-opens jdk.incubator.vector/jdk.incubator.vector=ALL-UNNAMED
+ * Vector64ConversionTests
+ */
+
 @Test
 public class Vector64ConversionTests extends AbstractVectorConversionTest {