src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.lir.amd64/src/org/graalvm/compiler/lir/amd64/AMD64ArrayEqualsOp.java

*** 35,44 ****
--- 35,45 ----
  import org.graalvm.compiler.asm.amd64.AMD64Assembler.ConditionFlag;
  import org.graalvm.compiler.asm.amd64.AMD64Assembler.OperandSize;
  import org.graalvm.compiler.asm.amd64.AMD64Assembler.SSEOp;
  import org.graalvm.compiler.asm.amd64.AMD64MacroAssembler;
  import org.graalvm.compiler.core.common.LIRKind;
+ import org.graalvm.compiler.core.common.NumUtil;
  import org.graalvm.compiler.lir.LIRInstructionClass;
  import org.graalvm.compiler.lir.Opcode;
  import org.graalvm.compiler.lir.asm.CompilationResultBuilder;
  import org.graalvm.compiler.lir.gen.LIRGeneratorTool;
  
*** 130,145 ****
          // Load array base addresses.
          masm.leaq(array1, new AMD64Address(asRegister(array1Value), arrayBaseOffset));
          masm.leaq(array2, new AMD64Address(asRegister(array2Value), arrayBaseOffset));
  
          // Get array length in bytes.
!         masm.imull(length, asRegister(lengthValue), arrayIndexScale);
          masm.movl(result, length); // copy
  
          if (supportsAVX2(crb.target)) {
              emitAVXCompare(crb, masm, result, array1, array2, length, trueLabel, falseLabel);
          } else if (supportsSSE41(crb.target)) {
              emitSSE41Compare(crb, masm, result, array1, array2, length, trueLabel, falseLabel);
          }
  
          emit8ByteCompare(crb, masm, result, array1, array2, length, trueLabel, falseLabel);
          emitTailCompares(masm, result, array1, array2, length, trueLabel, falseLabel);
--- 131,153 ----
          // Load array base addresses.
          masm.leaq(array1, new AMD64Address(asRegister(array1Value), arrayBaseOffset));
          masm.leaq(array2, new AMD64Address(asRegister(array2Value), arrayBaseOffset));
  
          // Get array length in bytes.
!         masm.movl(length, asRegister(lengthValue));
! 
!         if (arrayIndexScale > 1) {
!             masm.shll(length, NumUtil.log2Ceil(arrayIndexScale)); // scale length
!         }
! 
          masm.movl(result, length); // copy
  
          if (supportsAVX2(crb.target)) {
              emitAVXCompare(crb, masm, result, array1, array2, length, trueLabel, falseLabel);
          } else if (supportsSSE41(crb.target)) {
+             // this code is used for AVX as well because our backend correctly ensures that
+             // VEX-prefixed instructions are emitted if AVX is supported
              emitSSE41Compare(crb, masm, result, array1, array2, length, trueLabel, falseLabel);
          }
  
          emit8ByteCompare(crb, masm, result, array1, array2, length, trueLabel, falseLabel);
          emitTailCompares(masm, result, array1, array2, length, trueLabel, falseLabel);