[Bug target/110170] Sub-optimal conditional jumps in conditional-swap with floating point

["crazylht at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110170

--- Comment #8 from Hongtao.liu <crazylht at gmail dot com> ---
ix86_expand_sse_fp_minmax failed since rtx_equal_p (cmp_op0, if_true) is false, 

249(reg:DF 86 [ _1 ])  (if_true)
250(reg:DF 83 [ _2 ])  (if_false)
251(reg:DF 82 [ _1 ])  (cmp0_op0)
252(reg:DF 83 [ _2 ])  (cmp1_op1)

but here if_true is just a copy from cmp_op0 but with different REGNO,
rtx_equal_p seems too conservative here.

 85(code_label 26 13 17 3 4 (nil) [1 uses])
 86(note 17 26 5 3 [bb 3] NOTE_INSN_BASIC_BLOCK)
 87(insn 5 17 6 3 (set (reg:DF 86 [ _1 ])
 88        (reg:DF 82 [ _1 ])) "test.C":3:20 153 {*movdf_internal}
 89     (expr_list:REG_DEAD (reg:DF 82 [ _1 ])
 90        (nil)))
 91(insn 6 5 7 3 (set (reg:DF 82 [ _1 ])
 92        (reg:DF 83 [ _2 ])) "test.C":4:14 discrim 1 153 {*movdf_internal}
 93     (expr_list:REG_DEAD (reg:DF 83 [ _2 ])
 94        (nil)))
 95(insn 7 6 18 3 (set (reg:DF 83 [ _2 ])
 96        (reg:DF 86 [ _1 ])) "test.C":3:20 discrim 1 153 {*movdf_internal}
 97     (expr_list:REG_DEAD (reg:DF 86 [ _1 ])
 98        (nil)))


3812  if (rtx_equal_p (cmp_op0, if_true) && rtx_equal_p (cmp_op1, if_false))
 3813    is_min = true;
 3814  else if (rtx_equal_p (cmp_op1, if_true) && rtx_equal_p (cmp_op0,
if_false))
 3815    is_min = false;
 3816  else
 3817=>  return false;