On 1 April 2021 18:54:07 CEST, "H.J. Lu via Gcc-patches"
<gcc-patches@gcc.gnu.org> 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.
>
>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 } } }
This matches ia32 and the others as well (x32 and amd64 or x86_64) doesn't it.
>*/
>+/* { dg-final { scan-assembler-times "\\tiretq" 1 { target { ! ia32 }
>} } } */
So this is superfluous without a trailing anchor for the first, fwiw.
Thanks,
