[PATCH 3/9] mips: Optimize jit_andi further

[Paul Cercueil]

On MIPS r2+, when the mask is a high mask (consecutive bits set to 1,
starting at MSB), a middle mask (consecutive bits set to 1 in the
middle of the mask), or an inverted middle mask (consecutive bits set to
1 starting at MSB, consecutive bits set to 1 starting at LSB, bits set
to zero somewhere in the middle), it is possible to simplify the code
generation by using the EXT and INS opcodes and their variants.

This commit adds extr() and insr() helpers, which will use the right
opcodes according to the mask that will be used.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
---
 lib/jit_mips-cpu.c | 85 +++++++++++++++++++++++++++++++++++-----------
 1 file changed, 65 insertions(+), 20 deletions(-)

diff --git a/lib/jit_mips-cpu.c b/lib/jit_mips-cpu.c
index b81bd96..62c0bd5 100644
--- a/lib/jit_mips-cpu.c
+++ b/lib/jit_mips-cpu.c
@@ -111,6 +111,7 @@ typedef union {
 #  define can_sign_extend_short_p(im)  ((im) >= -32678 && (im) <= 32767)
 #  define can_zero_extend_short_p(im)  ((im) >= 0 && (im) <= 65535)
 #  define is_low_mask(im)              (((im) & 1) ? (__builtin_popcountl((im) 
+ 1) <= 1) : 0)
+#  define is_middle_mask(im)           ((im) ? (__builtin_popcountl((im) + (1 
<< __builtin_ctzl(im))) <= 1) : 0)
 #  define is_high_mask(im)             ((im) ? (__builtin_popcountl((im) + (1 
<< __builtin_ctzl(im))) == 0) : 0)
 #  define masked_bits_count(im)                __builtin_popcountl(im)
 #  define unmasked_bits_count(im)      (__WORDSIZE - masked_bits_count(im))
@@ -349,8 +350,12 @@ static void _nop(jit_state_t*,jit_int32_t);
 #  define DSRL32(rd,rt,sa)             rrit(rt,rd,sa,MIPS_DSRL32)
 #  define INS(rt,rs,pos,size)          
hrrrit(MIPS_SPECIAL3,rs,rt,pos+size-1,pos,MIPS_INS)
 #  define DINS(rt,rs,pos,size)         
hrrrit(MIPS_SPECIAL3,rs,rt,pos+size-1,pos,MIPS_DINS)
+#  define DINSU(rt,rs,pos,size)                
hrrrit(MIPS_SPECIAL3,rs,rt,pos+size-32-1,pos-32,MIPS_DINSU)
+#  define DINSM(rt,rs,pos,size)                
hrrrit(MIPS_SPECIAL3,rs,rt,pos+size-32-1,pos,MIPS_DINSM)
 #  define EXT(rt,rs,pos,size)          
hrrrit(MIPS_SPECIAL3,rs,rt,size-1,pos,MIPS_EXT)
 #  define DEXT(rt,rs,pos,size)         
hrrrit(MIPS_SPECIAL3,rs,rt,size-1,pos,MIPS_DEXT)
+#  define DEXTU(rt,rs,pos,size)                
hrrrit(MIPS_SPECIAL3,rs,rt,size-1,pos-32,MIPS_DEXTU)
+#  define DEXTM(rt,rs,pos,size)                
hrrrit(MIPS_SPECIAL3,rs,rt,size-32-1,pos,MIPS_DEXTM)
 #  define ROTR(rd,rt,sa)               hrrrit(MIPS_SPECIAL,1,rt,rd,sa,MIPS_SRL)
 #  define DROTR(rd,rt,sa)              
hrrrit(MIPS_SPECIAL,1,rt,rd,sa,MIPS_DSRL)
 #  define MFHI(rd)                     
rrr_t(_ZERO_REGNO,_ZERO_REGNO,rd,MIPS_MFHI)
@@ -415,6 +420,10 @@ static void _nop(jit_state_t*,jit_int32_t);
 #    define div(rs,rt)                 DDIV(rs,rt)
 #    define divu(rs,rt)                        DDIVU(rs,rt)
 #  endif
+#  define extr(rd,rt,lsb,nb)   _extr(_jit,rd,rt,lsb,nb)
+static void 
_extr(jit_state_t*,jit_int32_t,jit_int32_t,jit_int32_t,jit_int32_t);
+#  define insr(rd,rt,lsb,nb)   _insr(_jit,rd,rt,lsb,nb)
+static void 
_insr(jit_state_t*,jit_int32_t,jit_int32_t,jit_int32_t,jit_int32_t);
 #  define addi(r0,r1,i0)               _addi(_jit,r0,r1,i0)
 static void _addi(jit_state_t*,jit_int32_t,jit_int32_t,jit_word_t);
 #define addcr(r0,r1,r2)                        _addcr(_jit,r0,r1,r2)
@@ -812,6 +821,38 @@ _nop(jit_state_t *_jit, jit_int32_t i0)
     assert(i0 == 0);
 }
 
+static void
+_extr(jit_state_t *_jit, jit_int32_t r0, jit_int32_t r1,
+      jit_int32_t pos, jit_int32_t size)
+{
+    assert(size > 0);
+
+    if (__WORDSIZE == 32)
+        EXT(r0, r1, pos, size);
+    else if (pos >= 32)
+        DEXTU(r0, r1, pos, size);
+    else if (size > 32)
+        DEXTM(r0, r1, pos, size);
+    else
+        DEXT(r0, r1, pos, size);
+}
+
+static void
+_insr(jit_state_t *_jit, jit_int32_t r0, jit_int32_t r1,
+      jit_int32_t pos, jit_int32_t size)
+{
+    assert(size > 0);
+
+    if (__WORDSIZE == 32)
+        INS(r0, r1, pos, size);
+    else if (pos >= 32)
+        DINSU(r0, r1, pos, size);
+    else if (size > 32)
+        DINSM(r0, r1, pos, size);
+    else
+        DINS(r0, r1, pos, size);
+}
+
 static void
 _addi(jit_state_t *_jit, jit_int32_t r0, jit_int32_t r1, jit_word_t i0)
 {
@@ -1172,29 +1213,33 @@ _andi(jit_state_t *_jit, jit_int32_t r0, jit_int32_t 
r1, jit_word_t i0)
 {
     jit_int32_t                reg;
     if (can_zero_extend_short_p(i0))
-       ANDI(r0, r1, i0);
+        ANDI(r0, r1, i0);
     else if (is_low_mask(i0)) {
-#if defined(_MIPS_ARCH_MIPS32R2) || defined(_MIPS_ARCH_MIPS64R2)
-       if (masked_bits_count(i0) <= 32)
-#if defined(_MIPS_ARCH_MIPS32R2)
-               EXT(r0, r1, 0, masked_bits_count(i0));
-#else
-               DEXT(r0, r1, 0, masked_bits_count(i0));
-#endif
-       else
-#endif
-       {
-               lshi(r0, r1, unmasked_bits_count(i0));
-               rshi_u(r0, r0, unmasked_bits_count(i0));
-       }
+        if (jit_mips2_p())
+            extr(r0, r1, 0, masked_bits_count(i0));
+        else {
+            lshi(r0, r1, unmasked_bits_count(i0));
+            rshi_u(r0, r0, unmasked_bits_count(i0));
+        }
     } else if (is_high_mask(i0)) {
-       rshi(r0, r1, unmasked_bits_count(i0));
-       lshi(r0, r0, unmasked_bits_count(i0));
+        if (jit_mips2_p() && r0 == r1)
+            insr(r0, _ZERO_REGNO, 0, unmasked_bits_count(i0));
+        else {
+            rshi(r0, r1, unmasked_bits_count(i0));
+            lshi(r0, r0, unmasked_bits_count(i0));
+        }
+    } else if (jit_mips2_p() && is_middle_mask(i0)) {
+        extr(r0, r1, __builtin_ctzl(i0), masked_bits_count(i0));
+        lshi(r0, r0, __builtin_ctzl(i0));
+    } else if (jit_mips2_p() && is_middle_mask(~i0)) {
+        if (r0 != r1)
+            movr(r0, r1);
+        insr(r0, _ZERO_REGNO, __builtin_ctzl(~i0), masked_bits_count(~i0));
     } else {
-       reg = jit_get_reg(jit_class_gpr);
-       movi(rn(reg), i0);
-       AND(r0, r1, rn(reg));
-       jit_unget_reg(reg);
+        reg = jit_get_reg(jit_class_gpr);
+        movi(rn(reg), i0);
+        AND(r0, r1, rn(reg));
+        jit_unget_reg(reg);
     }
 }
 
-- 
2.35.1