| Message ID | 20221201100332.22226-4-gaofei@eswincomputing.com |
|---|---|
| State | New |
| Headers | show |
| Series | RISC-V: optimize stack manipulation in save-restore | expand |
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: <gaofei@eswincomputing.com> I split the patches as per Palmer's review comment. BR Fei >gcc/ChangeLog: > > * config/riscv/riscv.cc (riscv_first_stack_step): make codes more readable. > (riscv_expand_epilogue): likewise. >--- > gcc/config/riscv/riscv.cc | 17 ++++++++++------- > 1 file changed, 10 insertions(+), 7 deletions(-) > >diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc >index a50f2303032..95da08ffb3b 100644 >--- a/gcc/config/riscv/riscv.cc >+++ b/gcc/config/riscv/riscv.cc >@@ -4926,8 +4926,11 @@ riscv_first_stack_step (struct riscv_frame_info *frame, poly_int64 remaining_siz > if (SMALL_OPERAND (remaining_const_size)) > return remaining_const_size; > >+ poly_int64 callee_saved_first_step = >+ remaining_size - frame->frame_pointer_offset; >+ gcc_assert(callee_saved_first_step.is_constant ()); > HOST_WIDE_INT min_first_step = >- riscv_stack_align ((remaining_size - frame->frame_pointer_offset).to_constant()); >+ riscv_stack_align (callee_saved_first_step.to_constant ()); > HOST_WIDE_INT max_first_step = IMM_REACH / 2 - PREFERRED_STACK_BOUNDARY / 8; > HOST_WIDE_INT min_second_step = remaining_const_size - max_first_step; > gcc_assert (min_first_step <= max_first_step); >@@ -4935,7 +4938,7 @@ riscv_first_stack_step (struct riscv_frame_info *frame, poly_int64 remaining_siz > /* 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) >- && remaining_const_size % IMM_REACH < IMM_REACH / 2 >+ && remaining_const_size % IMM_REACH <= max_first_step > && remaining_const_size % IMM_REACH >= min_first_step) > return remaining_const_size % IMM_REACH; > >@@ -5129,14 +5132,14 @@ riscv_adjust_libcall_cfi_epilogue () > void > riscv_expand_epilogue (int style) > { >- /* Split the frame into two. STEP1 is the amount of stack we should >- deallocate before restoring the registers. STEP2 is the amount we >- should deallocate afterwards. >+ /* Split the frame into 3 steps. STEP1 is the amount of stack we should >+ deallocate before restoring the registers. STEP2 is the amount we >+ should deallocate afterwards including the callee saved regs. STEP3 >+ is the amount deallocated by save-restore libcall. > > Start off by assuming that no registers need to be restored. */ > struct riscv_frame_info *frame = &cfun->machine->frame; > unsigned mask = frame->mask; >- poly_int64 step1 = frame->total_size; > HOST_WIDE_INT step2 = 0; > bool use_restore_libcall = ((style == NORMAL_RETURN) > && riscv_use_save_libcall (frame)); >@@ -5223,7 +5226,7 @@ riscv_expand_epilogue (int style) > if (use_restore_libcall) > frame->mask = mask; /* Undo the above fib. */ > >- step1 -= step2 + libcall_size; >+ poly_int64 step1 = frame->total_size - step2 - libcall_size; > > /* Set TARGET to BASE + STEP1. */ > if (known_gt (step1, 0)) >-- >2.17.1
On 12/1/22 03:03, Fei Gao wrote: > gcc/ChangeLog: > > * config/riscv/riscv.cc (riscv_first_stack_step): make codes more readable. > (riscv_expand_epilogue): likewise. Thanks. I fixed up the capitalization and one or two whitespace errors and pushed this patch to the trunk. Thanks for your patience. jeff
diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc index a50f2303032..95da08ffb3b 100644 --- a/gcc/config/riscv/riscv.cc +++ b/gcc/config/riscv/riscv.cc @@ -4926,8 +4926,11 @@ riscv_first_stack_step (struct riscv_frame_info *frame, poly_int64 remaining_siz if (SMALL_OPERAND (remaining_const_size)) return remaining_const_size; + poly_int64 callee_saved_first_step = + remaining_size - frame->frame_pointer_offset; + gcc_assert(callee_saved_first_step.is_constant ()); HOST_WIDE_INT min_first_step = - riscv_stack_align ((remaining_size - frame->frame_pointer_offset).to_constant()); + riscv_stack_align (callee_saved_first_step.to_constant ()); HOST_WIDE_INT max_first_step = IMM_REACH / 2 - PREFERRED_STACK_BOUNDARY / 8; HOST_WIDE_INT min_second_step = remaining_const_size - max_first_step; gcc_assert (min_first_step <= max_first_step); @@ -4935,7 +4938,7 @@ riscv_first_stack_step (struct riscv_frame_info *frame, poly_int64 remaining_siz /* 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) - && remaining_const_size % IMM_REACH < IMM_REACH / 2 + && remaining_const_size % IMM_REACH <= max_first_step && remaining_const_size % IMM_REACH >= min_first_step) return remaining_const_size % IMM_REACH; @@ -5129,14 +5132,14 @@ riscv_adjust_libcall_cfi_epilogue () void riscv_expand_epilogue (int style) { - /* Split the frame into two. STEP1 is the amount of stack we should - deallocate before restoring the registers. STEP2 is the amount we - should deallocate afterwards. + /* Split the frame into 3 steps. STEP1 is the amount of stack we should + deallocate before restoring the registers. STEP2 is the amount we + should deallocate afterwards including the callee saved regs. STEP3 + is the amount deallocated by save-restore libcall. Start off by assuming that no registers need to be restored. */ struct riscv_frame_info *frame = &cfun->machine->frame; unsigned mask = frame->mask; - poly_int64 step1 = frame->total_size; HOST_WIDE_INT step2 = 0; bool use_restore_libcall = ((style == NORMAL_RETURN) && riscv_use_save_libcall (frame)); @@ -5223,7 +5226,7 @@ riscv_expand_epilogue (int style) if (use_restore_libcall) frame->mask = mask; /* Undo the above fib. */ - step1 -= step2 + libcall_size; + poly_int64 step1 = frame->total_size - step2 - libcall_size; /* Set TARGET to BASE + STEP1. */ if (known_gt (step1, 0))
gcc/ChangeLog: * config/riscv/riscv.cc (riscv_first_stack_step): make codes more readable. (riscv_expand_epilogue): likewise. --- gcc/config/riscv/riscv.cc | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-)