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
