src/jdk.incubator.foreign/share/classes/jdk/internal/foreign/AbstractMemorySegmentImpl.java

M AbstractMemorySegmentImpl.java

*** 147,164 ****
              return -1;
          }
  
          long i = 0;
          if (length > 7) {
              i = ArraysSupport.vectorizedMismatchLarge(
                      this.base(), this.min(),
                      that.base(), that.min(),
                      length, ArraysSupport.LOG2_ARRAY_BYTE_INDEX_SCALE);
              if (i >= 0) {
                  return i;
              }
!             i = length - ~i;
          }
          MemoryAddress thisAddress = this.baseAddress();
          MemoryAddress thatAddress = that.baseAddress();
          for (; i < length; i++) {
              if ((byte) BYTE_HANDLE.get(thisAddress, i) != (byte) BYTE_HANDLE.get(thatAddress, i)) {
--- 147,170 ----
              return -1;
          }
  
          long i = 0;
          if (length > 7) {
+             if ((byte) BYTE_HANDLE.get(this.baseAddress(), 0) != (byte) BYTE_HANDLE.get(that.baseAddress(), 0)) {
+                 return 0;
+             }
              i = ArraysSupport.vectorizedMismatchLarge(
                      this.base(), this.min(),
                      that.base(), that.min(),
                      length, ArraysSupport.LOG2_ARRAY_BYTE_INDEX_SCALE);
              if (i >= 0) {
                  return i;
              }
!             long remaining = ~i;
!             if (remaining > 7)
!                 throw new InternalError("remaining greater than 7: " + remaining);
!             i = length - remaining;
          }
          MemoryAddress thisAddress = this.baseAddress();
          MemoryAddress thatAddress = that.baseAddress();
          for (; i < length; i++) {
              if ((byte) BYTE_HANDLE.get(thisAddress, i) != (byte) BYTE_HANDLE.get(thatAddress, i)) {