Fold more boolean expressions

Thu Sep 20 13:34:00 GMT 2018

On Sat, Sep 15, 2018 at 8:01 AM MCC CS <mcccs@gmx.com> wrote:
>
> Sorry for doing the same mistake twice. Is this OK, and do
> I need to test it again after the first version of this
> patch?
>
> 2018-09-15 MCC CS <deswurstes@users.noreply.github.com>
>
>         gcc/
>         PR tree-optimization/87261
>         * match.pd: Add boolean optimizations,
>         fix whitespace.
>
> 2018-09-15 MCC CS <deswurstes@users.noreply.github.com>
>
>         gcc/testsuite/
>         PR tree-optimization/87261
>         * gcc.dg/pr87261.c: New test.
>
> Index: gcc/match.pd
> ===================================================================
> --- gcc/match.pd        (revision 264170)
> +++ gcc/match.pd        (working copy)
> @@ -92,7 +92,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>    IFN_FMA IFN_FMS IFN_FNMA IFN_FNMS)
>  (define_operator_list COND_TERNARY
>    IFN_COND_FMA IFN_COND_FMS IFN_COND_FNMA IFN_COND_FNMS)
> -
> +
>  /* As opposed to convert?, this still creates a single pattern, so
>     it is not a suitable replacement for convert? in all cases.  */
>  (match (nop_convert @0)
> @@ -106,7 +106,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>        && tree_nop_conversion_p (TREE_TYPE (type), TREE_TYPE (TREE_TYPE (@0))))))
>  /* This one has to be last, or it shadows the others.  */
>  (match (nop_convert @0)
> - @0)
> + @0)
>
>  /* Transform likes of (char) ABS_EXPR <(int) x> into (char) ABSU_EXPR <x>
>     ABSU_EXPR returns unsigned absolute value of the operand and the operand
> @@ -285,7 +285,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>       And not for _Fract types where we can't build 1.  */
>    (if (!integer_zerop (@0) && !ALL_FRACT_MODE_P (TYPE_MODE (type)))
>     { build_one_cst (type); }))
> - /* X / abs (X) is X < 0 ? -1 : 1.  */
> + /* X / abs (X) is X < 0 ? -1 : 1.  */
>   (simplify
>     (div:C @0 (abs @0))
>     (if (INTEGRAL_TYPE_P (type)
> @@ -921,6 +921,31 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>    (bitop:c @0 (bit_not (bitop:cs @0 @1)))
>    (bitop @0 (bit_not @1))))
>
> +/* (~x & y) | ~(x | y) -> ~x */
> +(simplify
> + (bit_ior:c (bit_and:c (bit_not@2 @0) @1) (bit_not (bit_ior:c @0 @1)))
> + @2)
> +
> +/* (x | y) ^ (x | ~y) -> ~x */
> +(simplify
> + (bit_xor:c (bit_ior:c @0 @1) (bit_ior:c @0 (bit_not @1)))
> + (bit_not @0))
> +
> +/* (x & y) | ~(x | y) -> ~(x ^ y) */
> +(simplify
> + (bit_ior:c (bit_and @0 @1) (bit_not:s (bit_ior:s @0 @1)))

I think this misses :cs on the bit_and.

> + (bit_not (bit_xor @0 @1)))
> +
> +/* (~x | y) ^ (x ^ y) -> x | ~y */
> +(simplify
> + (bit_xor:c (bit_ior:cs (bit_not @0) @1) (bit_xor:c @0 @1))
> + (bit_ior @0 (bit_not @1)))

:s on the bit_xor

> +/* (x ^ y) | ~(x | y) -> ~(x & y) */
> +(simplify
> + (bit_ior:c (bit_xor @0 @1) (bit_not:s (bit_ior @0 @1)))
> + (bit_not (bit_and @0 @1)))

:cs on the bit_xor, :s on the second bit_ior

Otherwise looks OK to me.

Thanks,
Richard.

>  /* (x | y) & ~x -> y & ~x */
>  /* (x & y) | ~x -> y | ~x */
>  (for bitop (bit_and bit_ior)
> @@ -1131,7 +1156,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>    (if (tree_nop_conversion_p (type, TREE_TYPE (@0))
>         && tree_nop_conversion_p (type, TREE_TYPE (@1)))
>     (mult (convert @0) (convert (negate @1)))))
> -
> +
>  /* -(A + B) -> (-B) - A.  */
>  (simplify
>   (negate (plus:c @0 negate_expr_p@1))
> @@ -3091,7 +3116,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>      (if (tree_int_cst_sgn (@1) < 0)
>       (scmp @0 @2)
>       (cmp @0 @2))))))
> -
> +
>  /* Simplify comparison of something with itself.  For IEEE
>     floating-point, we can only do some of these simplifications.  */
>  (for cmp (eq ge le)
> @@ -3162,11 +3187,11 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>          }
>        tree newtype
>          = (TYPE_PRECISION (TREE_TYPE (@0)) > TYPE_PRECISION (type1)
> -          ? TREE_TYPE (@0) : type1);
> +          ? TREE_TYPE (@0) : type1);
>      }
>      (if (TYPE_PRECISION (TREE_TYPE (@2)) > TYPE_PRECISION (newtype))
>       (cmp (convert:newtype @0) (convert:newtype @1))))))
> -
> +
>   (simplify
>    (cmp @0 REAL_CST@1)
>    /* IEEE doesn't distinguish +0 and -0 in comparisons.  */
> @@ -3414,7 +3439,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>             (FTYPE) N == CST -> 0
>             (FTYPE) N != CST -> 1.  */
>         (if (cmp == EQ_EXPR || cmp == NE_EXPR)
> -        { constant_boolean_node (cmp == NE_EXPR, type); })
> +        { constant_boolean_node (cmp == NE_EXPR, type); })
>         /* Otherwise replace with sensible integer constant.  */
>         (with
>          {
> @@ -3656,7 +3681,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>   (simplify
>    (cmp (bit_and@2 @0 integer_pow2p@1) @1)
>    (icmp @2 { build_zero_cst (TREE_TYPE (@0)); })))
> -
> +
>  /* If we have (A & C) != 0 ? D : 0 where C and D are powers of 2,
>     convert this into a shift followed by ANDing with D.  */
>  (simplify
> @@ -3876,7 +3901,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>          (if (cmp == LE_EXPR)
>          (ge (convert:st @0) { build_zero_cst (st); })
>          (lt (convert:st @0) { build_zero_cst (st); }))))))))))
> -
> +
>  (for cmp (unordered ordered unlt unle ungt unge uneq ltgt)
>   /* If the second operand is NaN, the result is constant.  */
>   (simplify
> @@ -4530,7 +4555,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>    (if (wi::to_wide (@1) == -1)
>     (rdiv { build_real (type, dconst1); } @0))))
>
> -/* Narrowing of arithmetic and logical operations.
> +/* Narrowing of arithmetic and logical operations.
>
>     These are conceptually similar to the transformations performed for
>     the C/C++ front-ends by shorten_binary_op and shorten_compare.  Long
> @@ -4602,7 +4627,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>       (convert (bit_and (op (convert:utype @0) (convert:utype @1))
>                (convert:utype @4))))))))
>
> -/* Transform (@0 < @1 and @0 < @2) to use min,
> +/* Transform (@0 < @1 and @0 < @2) to use min,
>     (@0 > @1 and @0 > @2) to use max */
>  (for logic (bit_and bit_and bit_and bit_and bit_ior bit_ior bit_ior bit_ior)
>       op    (lt      le      gt      ge      lt      le      gt      ge     )
> Index: gcc/testsuite/gcc.dg/pr87261.c
> ===================================================================
> --- gcc/testsuite/gcc.dg/pr87261.c      (nonexistent)
> +++ gcc/testsuite/gcc.dg/pr87261.c      (working copy)
> @@ -0,0 +1,35 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O -fdump-tree-original" } */
> +
> +int f1 (int a, int b)
> +{
> + return ~(a|b)|(~a&b);
> +}
> +
> +int f2 (int a, int b)
> +{
> + return (a|b)^(a|~b);
> +}
> +
> +/* { dg-final { scan-tree-dump-times "return \\~a;" 2 "original" } } */
> +
> +int f3 (int a, int b)
> +{
> + return ~(a|b)|(a&b);
> +}
> +
> +/* { dg-final { scan-tree-dump "return \\~\\(a \\^ b\\);" "original" } } */
> +
> +int f4 (int a, int b)
> +{
> + return a^b^(~a|b);
> +}
> +
> +/* { dg-final { scan-tree-dump "return \\~b \\| a;" "original" } } */
> +
> +int f5 (int a, int b)
> +{
> + return (a^b)|~(a|b);
> +}
> +
> +/* { dg-final { scan-tree-dump "return \\~\\(a \\& b\\);" "original" } } */