On Sun, Oct 29, 2023 at 5:41 PM Andrew Pinski <pins...@gmail.com> wrote:
>
> This moves a few more value_replacements simplifications to match.
> /* a == 1 ? b : a * b -> a * b */
> /* a == 1 ? b : b / a -> b / a */
> /* a == -1 ? b : a & b -> a & b */
>
> Also adds a testcase to show can we catch these where value_replacement would
> not
> (but other passes would).
>
> Bootstrapped and tested on x86_64-linux-gnu with no regressions.
OK.
> gcc/ChangeLog:
>
> * match.pd (`a == 1 ? b : a OP b`): New pattern.
> (`a == -1 ? b : a & b`): New pattern.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.dg/tree-ssa/phi-opt-value-4.c: New test.
> ---
> gcc/match.pd | 18 ++++++++++
> .../gcc.dg/tree-ssa/phi-opt-value-4.c | 36 +++++++++++++++++++
> 2 files changed, 54 insertions(+)
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/phi-opt-value-4.c
>
> diff --git a/gcc/match.pd b/gcc/match.pd
> index 9bc945ccada..6efa97cc6ae 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -4159,6 +4159,24 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> (cond (eq @0 integer_zerop) @1 (op@2 @1 @0))
> @2))
>
> +/* a == 1 ? b : b / a -> b / a */
> +(for op (trunc_div ceil_div floor_div round_div exact_div)
> + (simplify
> + (cond (eq @0 integer_onep) @1 (op@2 @1 @0))
> + @2))
> +
> +/* a == 1 ? b : a * b -> a * b */
> +(for op (mult)
> + (simplify
> + (cond (eq @0 integer_onep) @1 (op:c@2 @1 @0))
> + @2))
> +
> +/* a == -1 ? b : a & b -> a & b */
> +(for op (bit_and)
> + (simplify
> + (cond (eq @0 integer_all_onesp) @1 (op:c@2 @1 @0))
> + @2))
> +
> /* PTR == 0 ? 0 : &PTR->field -> PTR if field offset was 0. */
> (simplify
> (cond (eq @0 integer_zerop) integer_zerop ADDR_EXPR@1)
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-value-4.c
> b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-value-4.c
> new file mode 100644
> index 00000000000..380082cb463
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-value-4.c
> @@ -0,0 +1,36 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O1 -fdump-tree-fre3 -fdump-tree-phiopt1
> -fdump-tree-optimized" } */
> +
> +[[gnu::const]]
> +int constcall(int);
> +
> +int fdiv(int a, int b)
> +{
> + int c = b/a;
> + int t = constcall(c);
> + int d;
> + if (a == 1) d = b; else d = c;
> + return constcall(d) + t;
> +}
> +int fmult(int a, int b)
> +{
> + int c = b*a;
> + int t = constcall(c);
> + int d;
> + if (a == 1) d = b; else d = c;
> + return constcall(d) + t;
> +}
> +int fand(int a, int b)
> +{
> + int c = b&a;
> + int t = constcall(c);
> + int d;
> + if (a == -1) d = b; else d = c;
> + return constcall(d) + t;
> +}
> +
> +/* Should be able to optimize away the if statements in phiopt1. */
> +/* { dg-final { scan-tree-dump-not "if " "phiopt1" } } */
> +/* fre3 should be optimize each function to just `return constcall(a OP b) *
> 2;`. */
> +/* { dg-final { scan-tree-dump-times "constcall " 3 "fre3" } } */
> +/* { dg-final { scan-tree-dump-times "constcall " 3 "optimized" } } */
> --
> 2.39.3
>
