[PATCH] x86: Optimize jit_andi

[Paul Cercueil]

Use the same tricks found in jit_mips-cpu.c, to optimize jit_andi() on
x86/x86_64 when the immediate value is a "low mask" or a "high mask".

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
---
 lib/jit_x86-cpu.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/lib/jit_x86-cpu.c b/lib/jit_x86-cpu.c
index 76f90ec..126fca6 100644
--- a/lib/jit_x86-cpu.c
+++ b/lib/jit_x86-cpu.c
@@ -806,6 +806,9 @@ static void _patch_at(jit_state_t*, jit_word_t, jit_word_t);
 #    endif
 #  endif
 #  define jit_cmov_p()                 jit_cpu.cmov
+#  define is_low_mask(im)              (((im) & 1) ? (__builtin_popcountl((im) 
+ 1) <= 1) : 0)
+#  define is_high_mask(im)             ((im) ? (__builtin_popcountl((im) + (1 
<< __builtin_ctzl(im))) == 0) : 0)
+#  define unmasked_bits_count(im)      (__WORDSIZE - __builtin_popcountl(im))
 #endif
 
 #if CODE
@@ -1881,15 +1884,20 @@ _andi(jit_state_t *_jit, jit_int32_t r0, jit_int32_t 
r1, jit_word_t i0)
        ixorr(r0, r0);
     else if (i0 == -1)
        movr(r0, r1);
+    else if (r0 == r1 && can_sign_extend_int_p(i0))
+        iandi(r0, i0);
+    else if (is_low_mask(i0)) {
+        lshi(r0, r1, unmasked_bits_count(i0));
+        rshi_u(r0, r0, unmasked_bits_count(i0));
+    } else if (is_high_mask(i0)) {
+        rshi_u(r0, r1, unmasked_bits_count(i0));
+        lshi(r0, r0, unmasked_bits_count(i0));
+    }
     else if (r0 == r1) {
-       if (can_sign_extend_int_p(i0))
-           iandi(r0, i0);
-       else {
            reg = jit_get_reg(jit_class_gpr);
            movi(rn(reg), i0);
            iandr(r0, rn(reg));
            jit_unget_reg(reg);
-       }
     }
     else {
        movi(r0, i0);
-- 
2.43.0