On Thu, Apr 1, 2021 at 6:54 PM H.J. Lu <hjl.to...@gmail.com> wrote:
>
> Since uiret should be used only for user interrupt handler return, don't
> generate uiret in interrupt handler return with -mcmodel=kernel even if
> UINTR is enabled.
NAK, -mcmodel should not affect ISAs, in the same way it doesn't switch off SSE.
Uros.
> gcc/
>
> PR target/99870
> * config/i386/i386.md (interrupt_return): Don't generate uiret
> for -mcmodel=kernel.
>
> gcc/testsuite/
>
> * gcc.target/i386/pr99870.c: New test.
> ---
> gcc/config/i386/i386.md | 3 ++-
> gcc/testsuite/gcc.target/i386/pr99870.c | 19 +++++++++++++++++++
> 2 files changed, 21 insertions(+), 1 deletion(-)
> create mode 100644 gcc/testsuite/gcc.target/i386/pr99870.c
>
> diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
> index 9ff35d9a607..1055b4187b2 100644
> --- a/gcc/config/i386/i386.md
> +++ b/gcc/config/i386/i386.md
> @@ -13885,7 +13885,8 @@ (define_insn "interrupt_return"
> (unspec [(const_int 0)] UNSPEC_INTERRUPT_RETURN)]
> "reload_completed"
> {
> - return TARGET_64BIT ? (TARGET_UINTR ? "uiret" : "iretq") : "iret";
> + return TARGET_64BIT ? ((TARGET_UINTR && ix86_cmodel != CM_KERNEL)
> + ? "uiret" : "iretq") : "iret";
> })
>
> ;; Used by x86_machine_dependent_reorg to avoid penalty on single byte RET
> diff --git a/gcc/testsuite/gcc.target/i386/pr99870.c
> b/gcc/testsuite/gcc.target/i386/pr99870.c
> new file mode 100644
> index 00000000000..0dafa001ba9
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr99870.c
> @@ -0,0 +1,19 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -march=sapphirerapids -mgeneral-regs-only" } */
> +/* { dg-additional-options "-mcmodel=kernel" { target { ! ia32 } } } */
> +
> +void
> +__attribute__((interrupt))
> +fn (void *frame)
> +{
> +}
> +
> +typedef void (*fn_t) (void *) __attribute__((interrupt));
> +
> +fn_t fns[] =
> +{
> + fn,
> +};
> +
> +/* { dg-final { scan-assembler-times "\\tiret" 1 { target ia32 } } } */
> +/* { dg-final { scan-assembler-times "\\tiretq" 1 { target { ! ia32 } } } }
> */
> --
> 2.30.2
>
