On Fri, Nov 10, 2023 at 8:14 AM Jin Ma <ji...@linux.alibaba.com> wrote:
>
> The t0 register is used as a temporary register for interrupts, so it needs
> special treatment. It is necessary to avoid using "th.ldd" in the interrupt
> program to stop the subsequent operation of the t0 register, so they need to
> exchange positions in the function "riscv_for_each_saved_reg".
RISCV_PROLOGUE_TEMP_REGNUM needs indeed to be treated special
in case of ISRs and fcsr. This patch just moves the TARGET_XTHEADMEMPAIR
block after the ISR/fcsr block.
Reviewed-by: Christoph Müllner <christoph.muell...@vrull.eu>
>
> gcc/ChangeLog:
>
> * config/riscv/riscv.cc (riscv_for_each_saved_reg): Place the
> interrupt
> operation before the XTheadMemPair.
> ---
> gcc/config/riscv/riscv.cc | 56 +++++++++----------
> .../riscv/xtheadmempair-interrupt-fcsr.c | 18 ++++++
> 2 files changed, 46 insertions(+), 28 deletions(-)
> create mode 100644
> gcc/testsuite/gcc.target/riscv/xtheadmempair-interrupt-fcsr.c
>
> diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
> index e25692b86fc..fa2d4d4b779 100644
> --- a/gcc/config/riscv/riscv.cc
> +++ b/gcc/config/riscv/riscv.cc
> @@ -6346,6 +6346,34 @@ riscv_for_each_saved_reg (poly_int64 sp_offset,
> riscv_save_restore_fn fn,
> && riscv_is_eh_return_data_register (regno))
> continue;
>
> + /* In an interrupt function, save and restore some necessary CSRs in
> the stack
> + to avoid changes in CSRs. */
> + if (regno == RISCV_PROLOGUE_TEMP_REGNUM
> + && cfun->machine->interrupt_handler_p
> + && ((TARGET_HARD_FLOAT && cfun->machine->frame.fmask)
> + || (TARGET_ZFINX
> + && (cfun->machine->frame.mask & ~(1 <<
> RISCV_PROLOGUE_TEMP_REGNUM)))))
> + {
> + unsigned int fcsr_size = GET_MODE_SIZE (SImode);
> + if (!epilogue)
> + {
> + riscv_save_restore_reg (word_mode, regno, offset, fn);
> + offset -= fcsr_size;
> + emit_insn (gen_riscv_frcsr (RISCV_PROLOGUE_TEMP (SImode)));
> + riscv_save_restore_reg (SImode, RISCV_PROLOGUE_TEMP_REGNUM,
> + offset, riscv_save_reg);
> + }
> + else
> + {
> + riscv_save_restore_reg (SImode, RISCV_PROLOGUE_TEMP_REGNUM,
> + offset - fcsr_size, riscv_restore_reg);
> + emit_insn (gen_riscv_fscsr (RISCV_PROLOGUE_TEMP (SImode)));
> + riscv_save_restore_reg (word_mode, regno, offset, fn);
> + offset -= fcsr_size;
> + }
> + continue;
> + }
> +
> if (TARGET_XTHEADMEMPAIR)
> {
> /* Get the next reg/offset pair. */
> @@ -6376,34 +6404,6 @@ riscv_for_each_saved_reg (poly_int64 sp_offset,
> riscv_save_restore_fn fn,
> }
> }
>
> - /* In an interrupt function, save and restore some necessary CSRs in
> the stack
> - to avoid changes in CSRs. */
> - if (regno == RISCV_PROLOGUE_TEMP_REGNUM
> - && cfun->machine->interrupt_handler_p
> - && ((TARGET_HARD_FLOAT && cfun->machine->frame.fmask)
> - || (TARGET_ZFINX
> - && (cfun->machine->frame.mask & ~(1 <<
> RISCV_PROLOGUE_TEMP_REGNUM)))))
> - {
> - unsigned int fcsr_size = GET_MODE_SIZE (SImode);
> - if (!epilogue)
> - {
> - riscv_save_restore_reg (word_mode, regno, offset, fn);
> - offset -= fcsr_size;
> - emit_insn (gen_riscv_frcsr (RISCV_PROLOGUE_TEMP (SImode)));
> - riscv_save_restore_reg (SImode, RISCV_PROLOGUE_TEMP_REGNUM,
> - offset, riscv_save_reg);
> - }
> - else
> - {
> - riscv_save_restore_reg (SImode, RISCV_PROLOGUE_TEMP_REGNUM,
> - offset - fcsr_size, riscv_restore_reg);
> - emit_insn (gen_riscv_fscsr (RISCV_PROLOGUE_TEMP (SImode)));
> - riscv_save_restore_reg (word_mode, regno, offset, fn);
> - offset -= fcsr_size;
> - }
> - continue;
> - }
> -
> riscv_save_restore_reg (word_mode, regno, offset, fn);
> }
>
> diff --git a/gcc/testsuite/gcc.target/riscv/xtheadmempair-interrupt-fcsr.c
> b/gcc/testsuite/gcc.target/riscv/xtheadmempair-interrupt-fcsr.c
> new file mode 100644
> index 00000000000..d06f05f5c7c
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/riscv/xtheadmempair-interrupt-fcsr.c
> @@ -0,0 +1,18 @@
> +/* Verify that fcsr instructions emitted. */
> +/* { dg-do compile } */
> +/* { dg-require-effective-target hard_float } */
> +/* { dg-skip-if "" { *-*-* } { "-O0" "-O1" "-g" "-Oz" "-Os" "-flto" } } */
> +/* { dg-options "-march=rv64gc_xtheadmempair -mtune=thead-c906
> -funwind-tables" { target { rv64 } } } */
> +/* { dg-options "-march=rv32gc_xtheadmempair -mtune=thead-c906
> -funwind-tables" { target { rv32 } } } */
> +
> +
> +extern int foo (void);
> +
> +void __attribute__ ((interrupt))
> +sub (void)
> +{
> + foo ();
> +}
> +
> +/* { dg-final { scan-assembler-times "frcsr\t" 1 } } */
> +/* { dg-final { scan-assembler-times "fscsr\t" 1 } } */
>
> base-commit: e7f4040d9d6ec40c48ada940168885d7dde03af9
> --
> 2.17.1
>
