Re: [PATCH 3/3] MATCH: (convert)(zero_one !=/== 0/1) for outer type and zero_one type are the same

[Richard Biener <richard.guenther@gmail.com>]

On Sat, Dec 2, 2023 at 7:38 AM Andrew Pinski <quic_apinski@quicinc.com> wrote:
>
> When I moved two_value to match.pd, I removed the check for the {0,+-1}
> as I had placed it after the {0,+-1} case for cond in match.pd.
> In the case of {0,+-1} and non boolean, before we would optmize those
> case to just `(convert)a` but after we would get `(convert)(a != 0)`
> which was not handled anyways to just `(convert)a`.
> So this adds a pattern to match `(convert)(zeroone != 0)` and simplify
> to `(convert)zeroone`.
>
> Also this optimizes (convert)(zeroone == 0) into (zeroone^1) if the
> type match. This can only be done on the gimple level as if zeroone
> was defined by (a&1), fold will convert (a&1)^1 back into
> `(convert)(zeroone == 0)` and an infinite loop will happen.

So fold converts (a&1)^1 to (convert)(a&1 == 0)?  Can we fix (remove)
this instead or do we rely on that?

> Note the testcase pr69270.c needed a slight update due to not matching
> exactly a scan pattern, this update makes it more robust and will match
> before and afterwards and if there are other changes in this area too.
>
> Note the testcase gcc.target/i386/pr110790-2.c needs a slight update
> for better code generation in LP64 bit mode.
>
> Bootstrapped and tested on x86_64-linux-gnu with no regressions.

Otherwise OK.

Thanks,
Richard.

> gcc/ChangeLog:
>
>         PR tree-optimization/111972
>         PR tree-optimization/110637
>         * match.pd (`(convert)(zeroone !=/== CST)`): Match
>         and simplify to ((convert)zeroone){,^1}.
>
> gcc/testsuite/ChangeLog:
>
>         * gcc.dg/tree-ssa/pr110637-1.c: New test.
>         * gcc.dg/tree-ssa/pr110637-2.c: New test.
>         * gcc.dg/tree-ssa/pr110637-3.c: New test.
>         * gcc.dg/tree-ssa/pr111972-1.c: New test.
>         * gcc.dg/tree-ssa/pr69270.c: Update testcase.
>         * gcc.target/i386/pr110790-2.c: Update testcase.
>
> Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com>
> ---
>  gcc/match.pd                               | 21 +++++++++++++
>  gcc/testsuite/gcc.dg/tree-ssa/pr110637-1.c | 10 +++++++
>  gcc/testsuite/gcc.dg/tree-ssa/pr110637-2.c | 13 +++++++++
>  gcc/testsuite/gcc.dg/tree-ssa/pr110637-3.c | 14 +++++++++
>  gcc/testsuite/gcc.dg/tree-ssa/pr111972-1.c | 34 ++++++++++++++++++++++
>  gcc/testsuite/gcc.dg/tree-ssa/pr69270.c    |  4 +--
>  gcc/testsuite/gcc.target/i386/pr110790-2.c | 16 ++++++++--
>  7 files changed, 108 insertions(+), 4 deletions(-)
>  create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr110637-1.c
>  create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr110637-2.c
>  create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr110637-3.c
>  create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr111972-1.c
>
> diff --git a/gcc/match.pd b/gcc/match.pd
> index 4d554ba4721..656b2c9edda 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -3332,6 +3332,27 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>    (if (INTEGRAL_TYPE_P (TREE_TYPE (@0)) || POINTER_TYPE_P (TREE_TYPE (@0)))
>      (rcmp @0 @1))))
>
> +/* (type)([0,1]@a != 0) -> (type)a
> +   (type)([0,1]@a == 1) -> (type)a
> +   (type)([0,1]@a == 0) -> a ^ 1
> +   (type)([0,1]@a != 1) -> a ^ 1.  */
> +(for eqne (eq ne)
> + (simplify
> +  (convert (eqne zero_one_valued_p@0 INTEGER_CST@1))
> +  (if ((integer_zerop (@1) || integer_onep (@1)))
> +   (if ((eqne == EQ_EXPR) ^ integer_zerop (@1))
> +    (convert @0)
> +       /* a^1 can only be produced for gimple as
> +          fold has the exact opposite transformation
> +          for `(X & 1) ^ 1`.
> +          See `Fold ~X & 1 as (X & 1) == 0.`
> +          and `Fold (X ^ 1) & 1 as (X & 1) == 0.` in fold-const.cc.
> +          Only do this if the types match as (type)(a == 0) is
> +          canonical form normally, while `a ^ 1` is canonical when
> +          there is no type change. */
> +       (if (GIMPLE && types_match (type, TREE_TYPE (@0)))
> +        (bit_xor @0 { build_one_cst (type); } ))))))
> +
>  /* We can't reassociate at all for saturating types.  */
>  (if (!TYPE_SATURATING (type))
>
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr110637-1.c b/gcc/testsuite/gcc.dg/tree-ssa/pr110637-1.c
> new file mode 100644
> index 00000000000..3d03b0992a4
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr110637-1.c
> @@ -0,0 +1,10 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O1 -fdump-tree-optimized" } */
> +int f(int a)
> +{
> +        int b = (a & 1)!=0;
> +        return b;
> +}
> +
> +/* This should be optimized to just return (a & 1); */
> +/* { dg-final { scan-tree-dump-not " == " "optimized"} } */
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr110637-2.c b/gcc/testsuite/gcc.dg/tree-ssa/pr110637-2.c
> new file mode 100644
> index 00000000000..f1c5b90353a
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr110637-2.c
> @@ -0,0 +1,13 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O1 -fdump-tree-optimized" } */
> +int f(int a)
> +{
> +        int b = a & 1;
> +        int c = b == 0;
> +        return c;
> +}
> +
> +/* This should be optimized to just return `(a&1) ^ 1` or `(~a) & 1`. */
> +/* { dg-final { scan-tree-dump-not " == " "optimized"} } */
> +/* { dg-final { scan-tree-dump-times "~a" 1 "optimized"} } */
> +/* { dg-final { scan-tree-dump-times " & 1" 1 "optimized"} } */
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr110637-3.c b/gcc/testsuite/gcc.dg/tree-ssa/pr110637-3.c
> new file mode 100644
> index 00000000000..ce80146d9df
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr110637-3.c
> @@ -0,0 +1,14 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O1 -fdump-tree-optimized" } */
> +int f(int a)
> +{
> +        int b = a & 1;
> +        int c = b == 0;
> +        int d = ~a;
> +        int e = d & 1;
> +        return c == e;
> +}
> +
> +/* This should be optimized to just `return 1` */
> +/* { dg-final { scan-tree-dump-not " == " "optimized"} } */
> +/* { dg-final { scan-tree-dump-times "return 1" 1 "optimized"} } */
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr111972-1.c b/gcc/testsuite/gcc.dg/tree-ssa/pr111972-1.c
> new file mode 100644
> index 00000000000..0611808ed50
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr111972-1.c
> @@ -0,0 +1,34 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O1 -fdump-tree-phiopt" } */
> +double
> +foo() {
> +  long n3 = 3450000, xtra = 7270;
> +  long i,ix;
> +  long j;
> +  double Check;
> +
> +  /* Section 3, Conditional jumps */
> +  j = 0;
> +  {
> +    for (ix=0; ix<xtra; ix++)
> +      {
> +        for(i=0; i<n3; i++)
> +          {
> +            if(j==1)       j = 2;
> +            else           j = 3;
> +            if(j>2)        j = 0;
> +            else           j = 1;
> +            if(j<1)        j = 1;
> +            else           j = 0;
> +          }
> +      }
> +  }
> +  Check = Check + (double)j;
> +  return Check;
> +}
> +
> +/* the above if statements in loop should be optimized to just `j ^ 1`
> +   and should not be (type)(j != 1).  */
> +/* { dg-final { scan-tree-dump-not " != 1" "phiopt2"} } */
> +/* { dg-final { scan-tree-dump-times " \\^ 1" 1 "phiopt2"} } */
> +
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr69270.c b/gcc/testsuite/gcc.dg/tree-ssa/pr69270.c
> index 0d66cc4383f..b08ec9d6ddb 100644
> --- a/gcc/testsuite/gcc.dg/tree-ssa/pr69270.c
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr69270.c
> @@ -7,8 +7,8 @@
>  /* { dg-final { scan-tree-dump-times "Replaced .bufferstep_\[0-9\]+. with constant .1." 1 "dom3"} } */
>
>  /* And some assignments ought to fold down to constants.  */
> -/* { dg-final { scan-tree-dump-times "Folded to: _\[0-9\]+ = 1;" 1 "dom3"} } */
> -/* { dg-final { scan-tree-dump-times "Folded to: _\[0-9\]+ = 0;" 1 "dom3"} } */
> +/* { dg-final { scan-tree-dump-times "Folded to: (?:bufferstep)?_\[0-9\]+ = 1;" 1 "dom3"} } */
> +/* { dg-final { scan-tree-dump-times "Folded to: (?:bufferstep)?_\[0-9\]+ = 0;" 1 "dom3"} } */
>
>  /* The XOR operations should have been optimized to constants.  */
>  /* { dg-final { scan-tree-dump-not "bit_xor" "dom3"} } */
> diff --git a/gcc/testsuite/gcc.target/i386/pr110790-2.c b/gcc/testsuite/gcc.target/i386/pr110790-2.c
> index 8b9d650c6e9..16c73cb7465 100644
> --- a/gcc/testsuite/gcc.target/i386/pr110790-2.c
> +++ b/gcc/testsuite/gcc.target/i386/pr110790-2.c
> @@ -9,5 +9,17 @@ refmpn_tstbit_bad (mp_srcptr ptr, unsigned long bit)
>    return (((ptr)[(bit)/(32 - 0)] & (((mp_limb_t) 1L) << ((bit)%(32 - 0)))) != 0);
>  }
>
> -/* { dg-final { scan-assembler "bt\[ql\]" } } */
> -/* { dg-final { scan-assembler "setc" } } */
> +/* 32bit produces:
> +        btl     %eax, %edx
> +        setc    %al
> +        movzbl  %al, %eax
> + */
> +/* { dg-final { scan-assembler "bt\[ql\]" { target { ! lp64 } } } } */
> +/* { dg-final { scan-assembler "setc" { target {  ! lp64 } } } } */
> +
> +/* 64bit produces:
> +        shrq    %cl, %rax
> +        andl   $1, %eax
> + */
> +/* { dg-final { scan-assembler-times "shrq" 2 { target { lp64 } } } } */
> +/* { dg-final { scan-assembler-times "andl" 2 { target { lp64 } } } } */
> --
> 2.39.3
>