[PATCH 1/2] MIPS: add pattern insqisi_extended

[YunQiang Su <syq@gcc.gnu.org>]

This match pattern allows combination (zero_extract:DI 8, 24, QI)
with an sign-extend to 32bit INS instruction on TARGET_64BIT.

The problem is that, for SI mode, if the sign-bit is modified by
bitops, we will need a sign-extend operation.
Since 32bit INS instruction can be sure that result is sign-extended,
and the QImode src register is safe for INS, too.

(insn 19 18 20 2 (set (zero_extract:DI (reg/v:DI 200 [ val ])
            (const_int 8 [0x8])
            (const_int 24 [0x18]))
        (subreg:DI (reg:QI 205) 0)) "../xx.c":7:29 -1
     (nil))
(insn 20 19 23 2 (set (reg/v:DI 200 [ val ])
        (sign_extend:DI (subreg:SI (reg/v:DI 200 [ val ]) 0))) "../xx.c":7:29 -1
     (nil))

Combine try to merge them to:

(insn 20 19 23 2 (set (reg/v:DI 200 [ val ])
        (sign_extend:DI (ior:SI (and:SI (subreg:SI (reg/v:DI 200 [ val ]) 0)
                    (const_int 16777215 [0xffffff]))
                (ashift:SI (subreg:SI (reg:QI 205 [ MEM[(const unsigned char *)buf_8(D) + 3B] ]) 0)
                    (const_int 24 [0x18]))))) "../xx.c":7:29 18 {*insv_extended}
     (expr_list:REG_DEAD (reg:QI 205 [ MEM[(const unsigned char *)buf_8(D) + 3B] ])
        (nil)))

Let's accept this pattern.
Note: with this patch, we cannot get INS yet: rtx_cost treats
that the later one is more expensive than the previous 2.

gcc

	* config/mips/mips.md (insqisi_extended): New pattern.
---
 gcc/config/mips/mips.md | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/gcc/config/mips/mips.md b/gcc/config/mips/mips.md
index 0666310734e..6bc56b0d3da 100644
--- a/gcc/config/mips/mips.md
+++ b/gcc/config/mips/mips.md
@@ -4415,6 +4415,16 @@ (define_insn "*extzv_truncsi_exts"
   [(set_attr "type"     "arith")
    (set_attr "mode"     "SI")])
 
+(define_insn "*insqisi_extended"
+  [(set (match_operand:DI 0 "register_operand" "=d")
+	(sign_extend:DI
+	     (ior:SI (and:SI (subreg:SI (match_dup 0) 0)
+                    (const_int 16777215))
+		    (ashift:SI (subreg:SI (match_operand:QI 1 "register_operand" "d") 0)
+                (const_int 24)))))]
+  "TARGET_64BIT && !TARGET_MIPS16 && ISA_HAS_EXT_INS"
+  "ins\t%0,%1,24,8"
+  [(set_attr "mode" "SI")])
 
 (define_expand "insvmisalign<mode>"
   [(set (zero_extract:GPR (match_operand:BLK 0 "memory_operand")
-- 
2.39.2