On Sat, Sep 16, 2023 at 6:00 PM Andrew Pinski via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> `(a == CST) & a` can be either simplified to simplying `a == CST`
> or 0 depending on the first bit of the CST.
> This is an extension of the already pattern of `X & !X` and allows
> us to remove the 2 xfails on gcc.dg/binop-notand1a.c and
> gcc.dg/binop-notand4a.c.
>
> OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.
OK.
> PR tree-optimization/111431
>
> gcc/ChangeLog:
>
> * match.pd (`(a == CST) & a`): New pattern.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.dg/binop-notand1a.c: Remove xfail.
> * gcc.dg/binop-notand4a.c: Likewise.
> * gcc.c-torture/execute/pr111431-1.c: New test.
> * gcc.dg/binop-andeq1.c: New test.
> * gcc.dg/binop-andeq2.c: New test.
> * gcc.dg/binop-notand7.c: New test.
> * gcc.dg/binop-notand7a.c: New test.
> ---
> gcc/match.pd | 8 ++++
> .../gcc.c-torture/execute/pr111431-1.c | 39 +++++++++++++++++++
> gcc/testsuite/gcc.dg/binop-andeq1.c | 12 ++++++
> gcc/testsuite/gcc.dg/binop-andeq2.c | 14 +++++++
> gcc/testsuite/gcc.dg/binop-notand1a.c | 4 +-
> gcc/testsuite/gcc.dg/binop-notand4a.c | 4 +-
> gcc/testsuite/gcc.dg/binop-notand7.c | 12 ++++++
> gcc/testsuite/gcc.dg/binop-notand7a.c | 12 ++++++
> 8 files changed, 99 insertions(+), 6 deletions(-)
> create mode 100644 gcc/testsuite/gcc.c-torture/execute/pr111431-1.c
> create mode 100644 gcc/testsuite/gcc.dg/binop-andeq1.c
> create mode 100644 gcc/testsuite/gcc.dg/binop-andeq2.c
> create mode 100644 gcc/testsuite/gcc.dg/binop-notand7.c
> create mode 100644 gcc/testsuite/gcc.dg/binop-notand7a.c
>
> diff --git a/gcc/match.pd b/gcc/match.pd
> index ebb50ee0581..65960a1701e 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -5172,6 +5172,14 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> )
> )
>
> +/* `(a == CST) & a` can be simplified to `0` or `(a == CST)` depending
> + on the first bit of the CST. */
> +(simplify
> + (bit_and:c (convert@2 (eq @0 INTEGER_CST@1)) (convert? @0))
> + (if ((wi::to_wide (@1) & 1) != 0)
> + @2
> + { build_zero_cst (type); }))
> +
> /* Optimize
> # x_5 in range [cst1, cst2] where cst2 = cst1 + 1
> x_5 ? cstN ? cst4 : cst3
> diff --git a/gcc/testsuite/gcc.c-torture/execute/pr111431-1.c
> b/gcc/testsuite/gcc.c-torture/execute/pr111431-1.c
> new file mode 100644
> index 00000000000..a96dbadf2b5
> --- /dev/null
> +++ b/gcc/testsuite/gcc.c-torture/execute/pr111431-1.c
> @@ -0,0 +1,39 @@
> +int
> +foo (int a)
> +{
> + int b = a == 0;
> + return (a & b);
> +}
> +
> +#define function(vol,cst) \
> +__attribute__((noipa)) \
> +_Bool func_##cst##_##vol(vol int a) \
> +{ \
> + vol int b = a == cst; \
> + return (a & b); \
> +}
> +
> +#define funcdefs(cst) \
> +function(,cst) \
> +function(volatile,cst)
> +
> +#define funcs(f) \
> +f(0) \
> +f(1) \
> +f(5)
> +
> +funcs(funcdefs)
> +
> +#define test(cst) \
> +do { \
> + if(func_##cst##_(a) != func_##cst##_volatile(a))\
> + __builtin_abort(); \
> +} while(0);
> +int main(void)
> +{
> + for(int a = -10; a <= 10; a++)
> + {
> + funcs(test)
> + }
> +}
> +
> diff --git a/gcc/testsuite/gcc.dg/binop-andeq1.c
> b/gcc/testsuite/gcc.dg/binop-andeq1.c
> new file mode 100644
> index 00000000000..2a92b8f95df
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/binop-andeq1.c
> @@ -0,0 +1,12 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-optimized" } */
> +/* PR tree-optimization/111431 */
> +
> +int
> +foo (int a)
> +{
> + int b = a == 2;
> + return (a & b);
> +}
> +
> +/* { dg-final { scan-tree-dump-times "return 0" 1 "optimized" } } */
> diff --git a/gcc/testsuite/gcc.dg/binop-andeq2.c
> b/gcc/testsuite/gcc.dg/binop-andeq2.c
> new file mode 100644
> index 00000000000..895262fc17e
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/binop-andeq2.c
> @@ -0,0 +1,14 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-optimized" } */
> +/* PR tree-optimization/111431 */
> +
> +int
> +foo (int a)
> +{
> + int b = a == 1025;
> + return (a & b);
> +}
> +
> +/* { dg-final { scan-tree-dump-not "return 0" "optimized" } } */
> +/* { dg-final { scan-tree-dump-not " & " "optimized" } } */
> +/* { dg-final { scan-tree-dump-times " == 1025;" 1 "optimized" } } */
> diff --git a/gcc/testsuite/gcc.dg/binop-notand1a.c
> b/gcc/testsuite/gcc.dg/binop-notand1a.c
> index c7e932b2638..d94685eb4ce 100644
> --- a/gcc/testsuite/gcc.dg/binop-notand1a.c
> +++ b/gcc/testsuite/gcc.dg/binop-notand1a.c
> @@ -7,6 +7,4 @@ foo (char a, unsigned short b)
> return (a & !a) | (b & !b);
> }
>
> -/* As long as comparisons aren't boolified and casts from boolean-types
> - aren't preserved, the folding of X & !X to zero fails. */
> -/* { dg-final { scan-tree-dump-times "return 0" 1 "optimized" { xfail *-*-*
> } } } */
> +/* { dg-final { scan-tree-dump-times "return 0" 1 "optimized" } } */
> diff --git a/gcc/testsuite/gcc.dg/binop-notand4a.c
> b/gcc/testsuite/gcc.dg/binop-notand4a.c
> index dce6a5c7eb5..bd9c7cce638 100644
> --- a/gcc/testsuite/gcc.dg/binop-notand4a.c
> +++ b/gcc/testsuite/gcc.dg/binop-notand4a.c
> @@ -7,6 +7,4 @@ foo (unsigned char a, _Bool b)
> return (!a & a) | (b & !b);
> }
>
> -/* As long as comparisons aren't boolified and casts from boolean-types
> - aren't preserved, the folding of X & !X to zero fails. */
> -/* { dg-final { scan-tree-dump-times "return 0" 1 "optimized" { xfail *-*-*
> } } } */
> +/* { dg-final { scan-tree-dump-times "return 0" 1 "optimized" } } */
> diff --git a/gcc/testsuite/gcc.dg/binop-notand7.c
> b/gcc/testsuite/gcc.dg/binop-notand7.c
> new file mode 100644
> index 00000000000..c2bb6a0449d
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/binop-notand7.c
> @@ -0,0 +1,12 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-optimized" } */
> +/* PR tree-optimization/111431 */
> +
> +int
> +foo (int a)
> +{
> + int b = !a;
> + return (a & b);
> +}
> +
> +/* { dg-final { scan-tree-dump-times "return 0" 1 "optimized" } } */
> diff --git a/gcc/testsuite/gcc.dg/binop-notand7a.c
> b/gcc/testsuite/gcc.dg/binop-notand7a.c
> new file mode 100644
> index 00000000000..dd50916da61
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/binop-notand7a.c
> @@ -0,0 +1,12 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-optimized" } */
> +/* PR tree-optimization/111431 */
> +
> +unsigned
> +foo (int a)
> +{
> + int b = !a;
> + return (a & b);
> +}
> +
> +/* { dg-final { scan-tree-dump-times "return 0" 1 "optimized" } } */
> --
> 2.31.1
>
