Re: [PATCH] RISC-V missing __builtin_lceil and __builtin_lfloor

[Palmer Dabbelt <palmer@dabbelt.com>]

On Mon, 15 Aug 2022 17:44:35 PDT (-0700), kevinl@rivosinc.com wrote:
> Hello,
> Currently, __builtin_lceil and __builtin_lfloor doesn't generate an
> existing instruction fcvt, but rather calls ceil and floor from the
> library. This patch adds the missing iterator and attributes for lceil and
> lfloor to produce the optimized code.
>  The test cases check the correct generation of the fcvt instruction for
> float/double to int/long/long long. Passed the test in riscv-linux.
> Could this patch be committed?

Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>

Not sure if Kito had any comments for this one, but it looks good to me.

> gcc/ChangeLog:
>        Michael Collison  <collison@rivosinc.com>
>         * config/riscv/riscv.md (RINT): Add iterator for lceil and lround.
>         (rint_pattern): Add ceil and floor.
>         (rint_rm): Add rup and rdn.
>
> gcc/testsuite/ChangeLog:
>         Kevin Lee  <kevinl@rivosinc.com>
>         * gcc.target/riscv/lfloor-lceil.c: New test.
> ---
>  gcc/config/riscv/riscv.md                     | 13 ++-
>  gcc/testsuite/gcc.target/riscv/lfloor-lceil.c | 79 +++++++++++++++++++
>  2 files changed, 88 insertions(+), 4 deletions(-)
>  create mode 100644 gcc/testsuite/gcc.target/riscv/lfloor-lceil.c
>
> diff --git a/gcc/config/riscv/riscv.md b/gcc/config/riscv/riscv.md
> index c6399b1389e..070004fa7fe 100644
> --- a/gcc/config/riscv/riscv.md
> +++ b/gcc/config/riscv/riscv.md
> @@ -43,6 +43,9 @@ (define_c_enum "unspec" [
>    UNSPEC_LRINT
>    UNSPEC_LROUND
>
> +  UNSPEC_LCEIL
> +  UNSPEC_LFLOOR
> +
>    ;; Stack tie
>    UNSPEC_TIE
>  ])
> @@ -345,10 +348,12 @@ (define_mode_attr UNITMODE [(SF "SF") (DF "DF")])
>  ;; the controlling mode.
>  (define_mode_attr HALFMODE [(DF "SI") (DI "SI") (TF "DI")])
>
> -;; Iterator and attributes for floating-point rounding instructions.
> -(define_int_iterator RINT [UNSPEC_LRINT UNSPEC_LROUND])
> -(define_int_attr rint_pattern [(UNSPEC_LRINT "rint") (UNSPEC_LROUND
> "round")])
> -(define_int_attr rint_rm [(UNSPEC_LRINT "dyn") (UNSPEC_LROUND "rmm")])
> +;; Iterator and attributes for floating-point rounding instructions.f
> +(define_int_iterator RINT [UNSPEC_LRINT UNSPEC_LROUND UNSPEC_LCEIL
> UNSPEC_LFLOOR])
> +(define_int_attr rint_pattern [(UNSPEC_LRINT "rint") (UNSPEC_LROUND
> "round")
> +                             (UNSPEC_LCEIL "ceil") (UNSPEC_LFLOOR
> "floor")])
> +(define_int_attr rint_rm [(UNSPEC_LRINT "dyn") (UNSPEC_LROUND "rmm")
> +                        (UNSPEC_LCEIL "rup") (UNSPEC_LFLOOR "rdn")])
>
>  ;; Iterator and attributes for quiet comparisons.
>  (define_int_iterator QUIET_COMPARISON [UNSPEC_FLT_QUIET UNSPEC_FLE_QUIET])
> diff --git a/gcc/testsuite/gcc.target/riscv/lfloor-lceil.c
> b/gcc/testsuite/gcc.target/riscv/lfloor-lceil.c
> new file mode 100644
> index 00000000000..4d81c12cefa
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/riscv/lfloor-lceil.c
> @@ -0,0 +1,79 @@
> +/* { dg-do compile } */
> +/* { dg-options "-march=rv64gc -mabi=lp64d" } */
> +/* { dg-skip-if "" { *-*-* } { "-O0" "-Og" } } */
> +
> +int
> +ceil1(float i)
> +{
> +  return __builtin_lceil(i);
> +}
> +
> +long
> +ceil2(float i)
> +{
> +  return __builtin_lceil(i);
> +}
> +
> +long long
> +ceil3(float i)
> +{
> +  return __builtin_lceil(i);
> +}
> +
> +int
> +ceil4(double i)
> +{
> +  return __builtin_lceil(i);
> +}
> +
> +long
> +ceil5(double i)
> +{
> +  return __builtin_lceil(i);
> +}
> +
> +long long
> +ceil6(double i)
> +{
> +  return __builtin_lceil(i);
> +}
> +
> +int
> +floor1(float i)
> +{
> +  return __builtin_lfloor(i);
> +}
> +
> +long
> +floor2(float i)
> +{
> +  return __builtin_lfloor(i);
> +}
> +
> +long long
> +floor3(float i)
> +{
> +  return __builtin_lfloor(i);
> +}
> +
> +int
> +floor4(double i)
> +{
> +  return __builtin_lfloor(i);
> +}
> +
> +long
> +floor5(double i)
> +{
> +  return __builtin_lfloor(i);
> +}
> +
> +long long
> +floor6(double i)
> +{
> +  return __builtin_lfloor(i);
> +}
> +
> +/* { dg-final { scan-assembler-times "fcvt.l.s" 6 } } */
> +/* { dg-final { scan-assembler-times "fcvt.l.d" 6 } } */
> +/* { dg-final { scan-assembler-not "call" } } */