Gentle ping.
The patch I previously submitted:
| Date: Wed, 30 Nov 2022 00:38:08 -0800
| Subject: [PATCH] RISC-V: optimize stack manipulation in save-restore
| Message-ID: <gao...@eswincomputing.com>
I split the patches as per Palmer's review comment.
BR
Fei
>frame->total_size to remaining_size conversion is done as an independent patch
>without
>functionality change as per review comment.
>
>gcc/ChangeLog:
>
> * config/riscv/riscv.cc (riscv_first_stack_step): add a new function
>parameter remaining_size.
> (riscv_compute_frame_info): adapt new riscv_first_stack_step interface.
> (riscv_expand_prologue): likewise.
> (riscv_expand_epilogue): likewise.
>---
> gcc/config/riscv/riscv.cc | 48 +++++++++++++++++++--------------------
> 1 file changed, 24 insertions(+), 24 deletions(-)
>
>diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
>index 05bdba5ab4d..f0bbcd6d6be 100644
>--- a/gcc/config/riscv/riscv.cc
>+++ b/gcc/config/riscv/riscv.cc
>@@ -4634,7 +4634,7 @@ riscv_save_libcall_count (unsigned mask)
> They decrease stack_pointer_rtx but leave frame_pointer_rtx and
> hard_frame_pointer_rtx unchanged. */
>
>-static HOST_WIDE_INT riscv_first_stack_step (struct riscv_frame_info *frame);
>+static HOST_WIDE_INT riscv_first_stack_step (struct riscv_frame_info *frame,
>poly_int64 remaining_size);
>
> /* Handle stack align for poly_int. */
> static poly_int64
>@@ -4663,7 +4663,7 @@ riscv_compute_frame_info (void)
> save/restore t0. We check for this before clearing the frame struct. */
> if (cfun->machine->interrupt_handler_p)
> {
>- HOST_WIDE_INT step1 = riscv_first_stack_step (frame);
>+ HOST_WIDE_INT step1 = riscv_first_stack_step (frame, frame->total_size);
> if (! POLY_SMALL_OPERAND_P ((frame->total_size - step1)))
> interrupt_save_prologue_temp = true;
> }
>@@ -4913,45 +4913,45 @@ riscv_restore_reg (rtx reg, rtx mem)
> without adding extra instructions. */
>
> static HOST_WIDE_INT
>-riscv_first_stack_step (struct riscv_frame_info *frame)
>+riscv_first_stack_step (struct riscv_frame_info *frame, poly_int64
>remaining_size)
> {
>- HOST_WIDE_INT frame_total_constant_size;
>- if (!frame->total_size.is_constant ())
>- frame_total_constant_size
>- = riscv_stack_align (frame->total_size.coeffs[0])
>- - riscv_stack_align (frame->total_size.coeffs[1]);
>+ HOST_WIDE_INT remaining_const_size;
>+ if (!remaining_size.is_constant ())
>+ remaining_const_size
>+ = riscv_stack_align (remaining_size.coeffs[0])
>+ - riscv_stack_align (remaining_size.coeffs[1]);
> else
>- frame_total_constant_size = frame->total_size.to_constant ();
>+ remaining_const_size = remaining_size.to_constant ();
>
>- if (SMALL_OPERAND (frame_total_constant_size))
>- return frame_total_constant_size;
>+ if (SMALL_OPERAND (remaining_const_size))
>+ return remaining_const_size;
>
> HOST_WIDE_INT min_first_step =
>- RISCV_STACK_ALIGN ((frame->total_size -
>frame->frame_pointer_offset).to_constant());
>+ riscv_stack_align ((remaining_size -
>frame->frame_pointer_offset).to_constant());
> HOST_WIDE_INT max_first_step = IMM_REACH / 2 - PREFERRED_STACK_BOUNDARY / 8;
>- HOST_WIDE_INT min_second_step = frame_total_constant_size - max_first_step;
>+ HOST_WIDE_INT min_second_step = remaining_const_size - max_first_step;
> gcc_assert (min_first_step <= max_first_step);
>
> /* As an optimization, use the least-significant bits of the total frame
> size, so that the second adjustment step is just LUI + ADD. */
> if (!SMALL_OPERAND (min_second_step)
>- && frame_total_constant_size % IMM_REACH < IMM_REACH / 2
>- && frame_total_constant_size % IMM_REACH >= min_first_step)
>- return frame_total_constant_size % IMM_REACH;
>+ && remaining_const_size % IMM_REACH < IMM_REACH / 2
>+ && remaining_const_size % IMM_REACH >= min_first_step)
>+ return remaining_const_size % IMM_REACH;
>
> if (TARGET_RVC)
> {
> /* If we need two subtracts, and one is small enough to allow compressed
>- loads and stores, then put that one first. */
>+ loads and stores, then put that one first. */
> if (IN_RANGE (min_second_step, 0,
>- (TARGET_64BIT ? SDSP_REACH : SWSP_REACH)))
>- return MAX (min_second_step, min_first_step);
>+ (TARGET_64BIT ? SDSP_REACH : SWSP_REACH)))
>+ return MAX (min_second_step, min_first_step);
>
> /* If we need LUI + ADDI + ADD for the second adjustment step, then
>start
>- with the minimum first step, so that we can get compressed loads and
>- stores. */
>+ with the minimum first step, so that we can get compressed loads and
>+ stores. */
> else if (!SMALL_OPERAND (min_second_step))
>- return min_first_step;
>+ return min_first_step;
> }
>
> return max_first_step;
>@@ -5037,7 +5037,7 @@ riscv_expand_prologue (void)
> /* Save the registers. */
> if ((frame->mask | frame->fmask) != 0)
> {
>- HOST_WIDE_INT step1 = riscv_first_stack_step (frame);
>+ HOST_WIDE_INT step1 = riscv_first_stack_step (frame, frame->total_size);
> if (size.is_constant ())
> step1 = MIN (size.to_constant(), step1);
>
>@@ -5216,7 +5216,7 @@ riscv_expand_epilogue (int style)
> possible in the second step without going out of range. */
> if ((frame->mask | frame->fmask) != 0)
> {
>- step2 = riscv_first_stack_step (frame);
>+ step2 = riscv_first_stack_step (frame, frame->total_size);
> step1 -= step2;
> }
>
>--
>2.17.1
