ADD	$0x000fffff, R0, R1 // ADD $1048575, R0, R1    // 011680e2011041e2
	ADC	$0x000fffff, R0, R1 // ADC $1048575, R0, R1    // 0116a0e2011041e2
	SUB	$0x000fffff, R0, R1 // SUB $1048575, R0, R1    // 011640e2011081e2
	SBC	$0x000fffff, R0, R1 // SBC $1048575, R0, R1    // 0116c0e2011081e2
	RSB	$0x000fffff, R0, R1 // RSB $1048575, R0, R1    // 011660e2011041e2

(RISBGZ (MOVWZreg x) {r}) && r.InMerge(0xffffffff) != nil => (RISBGZ x {*r.InMerge(0xffffffff)})
(RISBGZ (MOVHZreg x) {r}) && r.InMerge(0x0000ffff) != nil => (RISBGZ x {*r.InMerge(0x0000ffff)})
(RISBGZ (MOVBZreg x) {r}) && r.InMerge(0x000000ff) != nil => (RISBGZ x {*r.InMerge(0x000000ff)})

// Absorb 'rotate then insert selected bits [into zero]' into zero extension.

   * are the "next" pointer (pointing to the next entry in the bucket chain), which will always be
   * less than or equal to the hashtable mask.
   *
   * <pre>
   * hash  = aaaaaaaa
   * mask  = 00000fff
   * next  = 00000bbb
   * entry = aaaaabbb
   * </pre>
   *
   * <p>The pointers in [size(), entries.length) are all "null" (UNSET).
   */
  @CheckForNull private transient int[] entries;

  /**

   * are the "next" pointer (pointing to the next entry in the bucket chain), which will always be
   * less than or equal to the hashtable mask.
   *
   * <pre>
   * hash  = aaaaaaaa
   * mask  = 00000fff
   * next  = 00000bbb
   * entry = aaaaabbb
   * </pre>
   *
   * <p>The pointers in [size(), entries.length) are all "null" (UNSET).
   */
  @CheckForNull private transient int[] entries;

  /**

   * the "next" pointer (pointing to the next entry in the bucket chain), which will always be less
   * than or equal to the hashtable mask.
   *
   * <pre>
   * hash  = aaaaaaaa
   * mask  = 00000fff
   * next  = 00000bbb
   * entry = aaaaabbb
   * </pre>
   *
   * <p>The pointers in [size(), entries.length) are all "null" (UNSET).
   */
  @VisibleForTesting @CheckForNull transient int[] entries;

   * the "next" pointer (pointing to the next entry in the bucket chain), which will always be less
   * than or equal to the hashtable mask.
   *
   * <pre>
   * hash  = aaaaaaaa
   * mask  = 00000fff
   * next  = 00000bbb
   * entry = aaaaabbb
   * </pre>
   *
   * <p>The pointers in [size(), entries.length) are all "null" (UNSET).
   */
  @VisibleForTesting @CheckForNull transient int[] entries;

	// cond: r.OutMerge(0x0000ffff) != nil
	// result: (RISBGZ x {*r.OutMerge(0x0000ffff)})
	for {
		if v_0.Op != OpS390XRISBGZ {
			break
		}
		r := auxToS390xRotateParams(v_0.Aux)
		x := v_0.Args[0]
		if !(r.OutMerge(0x0000ffff) != nil) {
			break
		}
		v.reset(OpS390XRISBGZ)
		v.Aux = s390xRotateParamsToAux(*r.OutMerge(0x0000ffff))
		v.AddArg(x)
		return true
	}