xtensa: Optimize '(~x & y)' to '((x & y) ^ y)'

In Xtensa ISA, there is no single machine instruction that calculates unary
bitwise negation.

gcc/ChangeLog:

	* config/xtensa/xtensa.md (*andsi3_bitcmpl):
	New insn_and_split pattern.

gcc/testsuite/ChangeLog:

	* gcc.target/xtensa/check_zero_byte.c: New.
This commit is contained in:
Takayuki 'January June' Suwa 2022-05-29 19:55:44 +09:00 committed by Max Filippov
parent 9777d446e2
commit e44e7face1
2 changed files with 29 additions and 0 deletions

View file

@ -601,6 +601,26 @@
(set_attr "mode" "SI")
(set_attr "length" "3,3")])
(define_insn_and_split "*andsi3_bitcmpl"
[(set (match_operand:SI 0 "register_operand" "=a")
(and:SI (not:SI (match_operand:SI 1 "register_operand" "r"))
(match_operand:SI 2 "register_operand" "r")))]
""
"#"
"&& can_create_pseudo_p ()"
[(set (match_dup 3)
(and:SI (match_dup 1)
(match_dup 2)))
(set (match_dup 0)
(xor:SI (match_dup 3)
(match_dup 2)))]
{
operands[3] = gen_reg_rtx (SImode);
}
[(set_attr "type" "arith")
(set_attr "mode" "SI")
(set_attr "length" "6")])
(define_insn "iorsi3"
[(set (match_operand:SI 0 "register_operand" "=a")
(ior:SI (match_operand:SI 1 "register_operand" "%r")

View file

@ -0,0 +1,9 @@
/* { dg-do compile } */
/* { dg-options "-O" } */
int check_zero_byte(int v)
{
return (v - 0x01010101) & ~v & 0x80808080;
}
/* { dg-final { scan-assembler-not "movi" } } */