tcg/mips: Conditionalize tcg_out_exts_i32_i64

Since TCG_TYPE_I32 values are kept sign-extended in registers, we need not
extend if the register matches.  This is already relied upon by comparisons.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
1 file changed