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

@@ -35,10 +35,11 @@
 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;
 

@@ -130,16 +131,23 @@
         // 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(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);