On Sat, Sep 5, 2026 at 8:35 AM wangjue <[email protected]> wrote:
>
> From: juewang <[email protected]>
>
> m68k_sched_issue_rate can be called for targets without a scheduling
> model. Return 1 for those targets instead of calling gcc_unreachable.
>
> Add tests for if-conversion costing on single-issue and multi-issue
> targets.
>
> Assisted-by: Codex (OpenAI)
>
> gcc/ChangeLog:
>
> * config/m68k/m68k.cc (m68k_sched_issue_rate): Return one for CPUs
> without a scheduling model.
Need a generic test which triggers ICE without the change.
> gcc/testsuite/ChangeLog:
>
> * gcc.target/riscv/ifcvt-parallel-cost-1.c: New test.
> * gcc.target/riscv/ifcvt-parallel-cost-2.c: Likewise.
> ---
> gcc/config/m68k/m68k.cc | 3 +-
> .../gcc.target/riscv/ifcvt-parallel-cost-1.c | 26 +++++++++++++++++
> .../gcc.target/riscv/ifcvt-parallel-cost-2.c | 29 +++++++++++++++++++
> 3 files changed, 56 insertions(+), 2 deletions(-)
> create mode 100644 gcc/testsuite/gcc.target/riscv/ifcvt-parallel-cost-1.c
> create mode 100644 gcc/testsuite/gcc.target/riscv/ifcvt-parallel-cost-2.c
>
> diff --git a/gcc/config/m68k/m68k.cc b/gcc/config/m68k/m68k.cc
> index b6134892883..074d82efb25 100644
> --- a/gcc/config/m68k/m68k.cc
> +++ b/gcc/config/m68k/m68k.cc
> @@ -6594,8 +6594,7 @@ m68k_sched_issue_rate (void)
> return 2;
>
> default:
> - gcc_unreachable ();
> - return 0;
> + return 1;
> }
> }
>
> diff --git a/gcc/testsuite/gcc.target/riscv/ifcvt-parallel-cost-1.c
> b/gcc/testsuite/gcc.target/riscv/ifcvt-parallel-cost-1.c
> new file mode 100644
> index 00000000000..1bec3f77dcd
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/riscv/ifcvt-parallel-cost-1.c
> @@ -0,0 +1,26 @@
> +/* { dg-do compile } */
> +/* { dg-skip-if "" { *-*-* } { "-O0" "-Og" "-Os" "-Oz" } } */
> +/* { dg-options "-O2 -march=rv64gc_zicond -mabi=lp64d -mtune=xt-c9501fdvt
> -mbranch-cost=3" } */
> +
> +extern void consume (void *, void *, void *);
> +
> +__attribute__ ((noinline, noclone))
> +void
> +select_three_pointers (long x, long y,
> + void *a0, void *a1,
> + void *b0, void *b1,
> + void *c0, void *c1)
> +{
> + if (x > y)
> + {
> + a0 = a1;
> + b0 = b1;
> + c0 = c1;
> + }
> +
> + consume (a0, b0, c0);
> +}
> +
> +/* { dg-final { scan-assembler-times "\\sczero\\.eqz\\s" 3 } } */
> +/* { dg-final { scan-assembler-times "\\sczero\\.nez\\s" 3 } } */
> +/* { dg-final { scan-assembler-not "\\s(?:bge|bgt|ble|blt)\\s" } } */
> diff --git a/gcc/testsuite/gcc.target/riscv/ifcvt-parallel-cost-2.c
> b/gcc/testsuite/gcc.target/riscv/ifcvt-parallel-cost-2.c
> new file mode 100644
> index 00000000000..6e1f9ed7849
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/riscv/ifcvt-parallel-cost-2.c
> @@ -0,0 +1,29 @@
> +/* { dg-do compile } */
> +/* { dg-skip-if "" { *-*-* } { "-O0" "-Og" "-Os" "-Oz" } } */
> +/* { dg-options "-O2 -march=rv64gc_zicond -mabi=lp64d -mtune=generic
> -mbranch-cost=3" } */
> +
> +extern void consume (void *, void *, void *);
> +
> +__attribute__ ((noinline, noclone))
> +void
> +select_three_pointers_generic (long x, long y,
> + void *a0, void *a1,
> + void *b0, void *b1,
> + void *c0, void *c1)
> +{
> + if (x >= y)
> + {
> + a0 = a1;
> + b0 = b1;
> + c0 = c1;
> + }
> +
> + consume (a0, b0, c0);
> +}
> +
> +/* The generic tuning model has an issue rate of one, so the three pointer
> + selections are not profitable at a branch cost of three. */
> +
> +/* { dg-final { scan-assembler-times "\\sbge\\s" 1 } } */
> +/* { dg-final { scan-assembler-not "\\sczero\\.eqz\\s" } } */
> +/* { dg-final { scan-assembler-not "\\sczero\\.nez\\s" } } */
> --
> 2.34.1
>
--
H.J.
