8279668: x86: AVX2 versions of vpxor should be asserted

Reviewed-by: goetz
Backport-of: 2bbeae3f056243a224b0bda021f16cdcbee3b3d6

src/hotspot/cpu/x86/assembler_x86.cpp

@@ -6539,6 +6539,9 @@ void Assembler::pxor(XMMRegister dst, XMMRegister src) {
 
 void Assembler::vpxor(XMMRegister dst, XMMRegister nds, XMMRegister src, int vector_len) {
   assert(UseAVX > 0, "requires some form of AVX");
+  assert(vector_len == AVX_128bit ? VM_Version::supports_avx() :
+         vector_len == AVX_256bit ? VM_Version::supports_avx2() :
+         vector_len == AVX_512bit ? VM_Version::supports_evex() : 0, "");
   InstructionAttr attributes(vector_len, /* vex_w */ false, /* legacy_mode */ false, /* no_mask_reg */ true, /* uses_vl */ true);
   int encode = vex_prefix_and_encode(dst->encoding(), nds->encoding(), src->encoding(), VEX_SIMD_66, VEX_OPCODE_0F, &attributes);
   emit_int8((unsigned char)0xEF);
@@ -6547,6 +6550,9 @@ void Assembler::vpxor(XMMRegister dst, XMMRegister nds, XMMRegister src, int vec
 
 void Assembler::vpxor(XMMRegister dst, XMMRegister nds, Address src, int vector_len) {
   assert(UseAVX > 0, "requires some form of AVX");
+  assert(vector_len == AVX_128bit ? VM_Version::supports_avx() :
+         vector_len == AVX_256bit ? VM_Version::supports_avx2() :
+         vector_len == AVX_512bit ? VM_Version::supports_evex() : 0, "");
   InstructionMark im(this);
   InstructionAttr attributes(vector_len, /* vex_w */ false, /* legacy_mode */ false, /* no_mask_reg */ true, /* uses_vl */ true);
   attributes.set_address_attributes(/* tuple_type */ EVEX_FV, /* input_size_in_bits */ EVEX_32bit);

src/hotspot/cpu/x86/macroAssembler_x86.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2022, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -1340,8 +1340,14 @@ class MacroAssembler: public Assembler {
   void vpxor(XMMRegister dst, XMMRegister nds, AddressLiteral src, int vector_len, Register scratch_reg = rscratch1);
 
   // Simple version for AVX2 256bit vectors
-  void vpxor(XMMRegister dst, XMMRegister src) { Assembler::vpxor(dst, dst, src, true); }
-  void vpxor(XMMRegister dst, Address src) { Assembler::vpxor(dst, dst, src, true); }
+  void vpxor(XMMRegister dst, XMMRegister src) {
+    assert(UseAVX >= 2, "Should be at least AVX2");
+    Assembler::vpxor(dst, dst, src, AVX_256bit);
+  }
+  void vpxor(XMMRegister dst, Address src) {
+    assert(UseAVX >= 2, "Should be at least AVX2");
+    Assembler::vpxor(dst, dst, src, AVX_256bit);
+  }
 
   void vinserti128(XMMRegister dst, XMMRegister nds, XMMRegister src, uint8_t imm8) {
     if (UseAVX > 2 && VM_Version::supports_avx512novl()) {