Jeffrey Law <[email protected]> writes:
> diff --git a/gcc/simplify-rtx.cc b/gcc/simplify-rtx.cc
> index bf625cdaf608..365bb9db1930 100644
> --- a/gcc/simplify-rtx.cc
> +++ b/gcc/simplify-rtx.cc
> @@ -3897,6 +3897,101 @@ simplify_context::simplify_binary_operation_1
> (rtx_code code,
> && negated_ops_p (XEXP (op0, 0), op1))
> return simplify_gen_binary (IOR, mode, XEXP (op0, 1), op1);
>
> + /* (ior (and (A C1) (and (not (A) C2))) can be converted
Bracketing typo: (not A) rather than (not (A))
> + into (and (xor (A C2) (C1 + C2))) when there are no bits
and here: (and (xor A C2) (C1 + C2))
> + in common between C1 and C2. */
> + if (GET_CODE (op0) == AND
> + && GET_CODE (op1) == AND
> + && GET_CODE (XEXP (op1, 0)) == NOT
> + && rtx_equal_p (XEXP (op0, 0), XEXP (XEXP (op1, 0), 0))
> + && CONST_INT_P (XEXP (op0, 1))
> + && CONST_INT_P (XEXP (op1, 1))
> + && (INTVAL (XEXP (op0, 1)) & INTVAL (XEXP (op1, 1))) == 0)
> + {
> + rtx c = GEN_INT (INTVAL (XEXP (op0, 1)) + INTVAL (XEXP (op1, 1)));
> +
> + tem = simplify_gen_binary (XOR, mode, XEXP (op0, 0), XEXP (op1, 1));
> + if (tem)
> + {
> + tem = simplify_gen_binary (AND, mode, tem, c);
> + if (tem)
> + return tem;
> + }
> + }
> +
> + /* Same thing, but operand order is reversed for the outer IOR. */
> + if (GET_CODE (op0) == AND
> + && GET_CODE (op1) == AND
> + && GET_CODE (XEXP (op0, 0)) == NOT
> + && rtx_equal_p (XEXP (op1, 0), XEXP (XEXP (op0, 0), 0))
> + && CONST_INT_P (XEXP (op0, 1))
> + && CONST_INT_P (XEXP (op1, 1))
> + && (INTVAL (XEXP (op0, 1)) & INTVAL (XEXP (op1, 1))) == 0)
> + {
> + rtx c = GEN_INT (INTVAL (XEXP (op0, 1)) + INTVAL (XEXP (op1, 1)));
> +
> + tem = simplify_gen_binary (XOR, mode, XEXP (op1, 0), XEXP (op0, 1));
> + if (tem)
> + {
> + tem = simplify_gen_binary (AND, mode, tem, c);
> + if (tem)
> + return tem;
> + }
> + }
> +
> + /* Another variant seen on some backends, particularly those with
> + sub-word operations. For these cases we have to know there is no
> + carry from the PLUS into relevant bits. In practice that means
> + it's only valid for the uppermost bit. */
I think this is different enough that it's worth giving the expression
in the comment, i.e.
(ior (and A C1) (plus (and A C1) C2))
It took me a while to work that out from the condition :)
I wondered whether this one could/should be generalised to use
nonzero_bits, rather than checking specifically for (and A C1).
That is,
(ior X (plus X C))
(or the reverse, for simple X) is equivalent to (ior X C)
if the low bit of C is above the highest nonzero bit of X.
In the above example, that would give us:
(ior (and A C1) C2)
which admittedly is different from the expansion in the patch,
but is equally simple. This is one of those unfortunate cases where
there are many ways of writing the same thing...
The (ior X (plus X C)) with nonzero_bits thing works for xor or ior in
place of plus.
> + if (GET_CODE (op0) == AND
> + && GET_CODE (op1) == PLUS
> + && GET_CODE (XEXP (op1, 0)) == AND
> + && rtx_equal_p (XEXP (op0, 0), XEXP (XEXP (op1, 0), 0))
> + && CONST_INT_P (XEXP (op0, 1))
> + && CONST_INT_P (XEXP (op1, 1))
> + && CONST_INT_P (XEXP (XEXP (op1, 0), 1))
> + && INTVAL (XEXP (op1, 1)) == INTVAL (XEXP (XEXP (op1, 0), 1))
> + && GET_MODE_BITSIZE (GET_MODE (op1)).is_constant ()
> + && ((INTVAL (XEXP (op1, 1)) & GET_MODE_MASK (GET_MODE (op1)))
> + == HOST_WIDE_INT_1U << (GET_MODE_BITSIZE (GET_MODE
> (op1)).to_constant () - 1))
> + && (INTVAL (XEXP (op0, 1)) & INTVAL (XEXP (op1, 1))) == 0)
> + {
> + rtx c = GEN_INT (INTVAL (XEXP (op0, 1)) + INTVAL (XEXP (op1, 1)));
> +
> + tem = simplify_gen_binary (XOR, mode, XEXP (op0, 0), XEXP (op1, 1));
> + if (tem)
> + {
> + tem = simplify_gen_binary (AND, mode, tem, c);
> + if (tem)
> + return tem;
> + }
> + }
> +
> + /* And its variant with the operands of the outer AND reversed. */
> + if (GET_CODE (op1) == AND
> + && GET_CODE (op0) == PLUS
> + && GET_CODE (XEXP (op0, 0)) == AND
> + && rtx_equal_p (XEXP (op1, 0), XEXP (XEXP (op0, 0), 0))
> + && CONST_INT_P (XEXP (op1, 1))
> + && CONST_INT_P (XEXP (op0, 1))
> + && CONST_INT_P (XEXP (XEXP (op0, 0), 1))
> + && INTVAL (XEXP (op0, 1)) == INTVAL (XEXP (XEXP (op0, 0), 1))
> + && GET_MODE_BITSIZE (GET_MODE (op0)).is_constant ()
> + && ((INTVAL (XEXP (op0, 1)) & GET_MODE_MASK (GET_MODE (op0)))
> + == HOST_WIDE_INT_1U << (GET_MODE_BITSIZE (GET_MODE
> (op0)).to_constant () - 1))
> + && (INTVAL (XEXP (op1, 1)) & INTVAL (XEXP (op0, 1))) == 0)
> + {
> + rtx c = GEN_INT (INTVAL (XEXP (op1, 1)) + INTVAL (XEXP (op0, 1)));
> +
> + tem = simplify_gen_binary (XOR, mode, XEXP (op1, 0), XEXP (op0, 1));
> + if (tem)
> + {
> + tem = simplify_gen_binary (AND, mode, tem, c);
> + if (tem)
> + return tem;
> + }
> + }
> +
How about putting this in a for loop:
for (int i = 0; i < 2; ++i)
{
}
so that each transform needs to be written once? This seems like a
really large amount of code to cut-&-paste, and it would be easy for
mistakes to be made when editing in future.
Sorry for being awkward :)
Richard
> tem = simplify_with_subreg_not (code, mode, op0, op1);
> if (tem)
> return tem;
> diff --git a/gcc/testsuite/gcc.target/riscv/pr80770.c
> b/gcc/testsuite/gcc.target/riscv/pr80770.c
> new file mode 100644
> index 000000000000..4dafe3955f05
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/riscv/pr80770.c
> @@ -0,0 +1,150 @@
> +/* { dg-do compile } */
> +/* { dg-additional-options "-std=gnu99" } */
> +/* { dg-skip-if "" { *-*-* } { "-O0" "-O1" } } */
> +
> +
> +struct S {
> + _Bool b0: 1;
> + _Bool b1: 1;
> + _Bool b2: 1;
> + _Bool b3: 1;
> + _Bool b4: 1;
> + _Bool b5: 1;
> + _Bool b6: 1;
> + _Bool b7: 1;
> + _Bool b8: 1;
> + _Bool b9: 1;
> + _Bool b10: 1;
> + _Bool b11: 1;
> + _Bool b12: 1;
> + _Bool b13: 1;
> + _Bool b14: 1;
> + _Bool b15: 1;
> + _Bool b16: 1;
> + _Bool b17: 1;
> + _Bool b18: 1;
> + _Bool b19: 1;
> + _Bool b20: 1;
> + _Bool b21: 1;
> + _Bool b22: 1;
> + _Bool b23: 1;
> + _Bool b24: 1;
> + _Bool b25: 1;
> + _Bool b26: 1;
> + _Bool b27: 1;
> + _Bool b28: 1;
> + _Bool b29: 1;
> + _Bool b30: 1;
> + _Bool b31: 1;
> + _Bool b32: 1;
> + _Bool b33: 1;
> + _Bool b34: 1;
> + _Bool b35: 1;
> + _Bool b36: 1;
> + _Bool b37: 1;
> + _Bool b38: 1;
> + _Bool b39: 1;
> + _Bool b40: 1;
> + _Bool b41: 1;
> + _Bool b42: 1;
> + _Bool b43: 1;
> + _Bool b44: 1;
> + _Bool b45: 1;
> + _Bool b46: 1;
> + _Bool b47: 1;
> + _Bool b48: 1;
> + _Bool b49: 1;
> + _Bool b50: 1;
> + _Bool b51: 1;
> + _Bool b52: 1;
> + _Bool b53: 1;
> + _Bool b54: 1;
> + _Bool b55: 1;
> + _Bool b56: 1;
> + _Bool b57: 1;
> + _Bool b58: 1;
> + _Bool b59: 1;
> + _Bool b60: 1;
> + _Bool b61: 1;
> + _Bool b62: 1;
> + _Bool b63: 1;
> +};
> +
> +#define T(N) void fb##N (struct S *s) { s->b##N = !s->b##N; }
> +
> +T(0)
> +T(1)
> +T(2)
> +T(3)
> +T(4)
> +T(5)
> +T(6)
> +T(7)
> +T(8)
> +T(9)
> +T(10)
> +T(11)
> +T(12)
> +T(13)
> +T(14)
> +T(15)
> +T(16)
> +T(17)
> +T(18)
> +T(19)
> +T(20)
> +T(21)
> +T(22)
> +T(23)
> +T(24)
> +T(25)
> +T(26)
> +T(27)
> +T(28)
> +T(29)
> +T(30)
> +T(31)
> +#if __riscv_xlen == 64
> +T(32)
> +T(33)
> +T(34)
> +T(35)
> +T(36)
> +T(37)
> +T(38)
> +T(39)
> +T(40)
> +T(41)
> +T(42)
> +T(43)
> +T(44)
> +T(45)
> +T(46)
> +T(47)
> +T(48)
> +T(49)
> +T(50)
> +T(51)
> +T(52)
> +T(53)
> +T(54)
> +T(55)
> +T(56)
> +T(57)
> +T(58)
> +T(59)
> +T(60)
> +T(61)
> +T(62)
> +T(63)
> +#endif
> +
> +/* { dg-final { scan-assembler-times "lbu\t" 64 { target rv64 } } } */
> +/* { dg-final { scan-assembler-times "lbu\t" 32 { target rv32 } } } */
> +
> +/* { dg-final { scan-assembler-times "xori\t" 64 { target rv64 } } } */
> +/* { dg-final { scan-assembler-times "xori\t" 32 { target rv32 } } } */
> +
> +
> +/* { dg-final { scan-assembler-times "sb\t" 64 { target rv64 } } } */
> +/* { dg-final { scan-assembler-times "sb\t" 32 { target rv32 } } } */
