| Message ID | CA+yXCZA1VmmZKLuXof0HydU-cvzpfDt3muCPYcZ8bgQwHfrFCg@mail.gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | RISC-V: Make sure stack is always aligned during adjusting | expand |
On Wed, Apr 18, 2018 at 4:59 AM, Kito Cheng <kito.cheng@gmail.com> wrote: + HOST_WIDE_INT min_first_step = + RISCV_STACK_ALIGN (frame->total_size - frame->fp_sp_offset); + HOST_WIDE_INT max_first_step = + ROUND_DOWN (IMM_REACH / 2 - PREFERRED_STACK_BOUNDARY / 8, + PREFERRED_STACK_BOUNDARY / 8); + HOST_WIDE_INT min_second_step = + RISCV_STACK_ALIGN (frame->total_size - max_first_step); IMM_REACH and PREFERRED_STACK_BOUNDARY are aligned values, so I don't see the point of rounding max_first_step. Similarly, frame->total_size and max_first_step are aligned values, so I don't see the point of rounding min_second_step. I do see that rounding min_first_step is useful. I'd like to add just that one statement change unless you have a reason for the others. I tested this with the following + if (min_first_step != RISCV_STACK_ALIGN (min_first_step)) + abort (); + if (max_first_step != RISCV_STACK_ALIGN (max_first_step)) + abort (); + if (min_second_step != RISCV_STACK_ALIGN (min_second_step)) + abort (); doing 32/64 elf/linux cross builds and testsuite runs. It failed for a 32-bit target before I rounded min_first_step. With that one change, I saw no further failures. Jim
From cf75c573ec9c8e5071e54a3cfba377fd0cb5bf3d Mon Sep 17 00:00:00 2001 From: Kito Cheng <kito.cheng@gmail.com> Date: Wed, 18 Apr 2018 17:51:35 +0800 Subject: [PATCH] RISC-V: Make sure stack is always aligned during adjusting stack. gcc/ChangeLog: 2018-04-18 Kito Cheng <kito.cheng@gmail.com> * config/riscv/riscv.c (riscv_first_stack_step): Round up min step and round down max step to make sure stack always aligned. --- gcc/config/riscv/riscv.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/gcc/config/riscv/riscv.c b/gcc/config/riscv/riscv.c index 2870177fa97..eca1cacf015 100644 --- a/gcc/config/riscv/riscv.c +++ b/gcc/config/riscv/riscv.c @@ -3507,9 +3507,13 @@ riscv_first_stack_step (struct riscv_frame_info *frame) if (SMALL_OPERAND (frame->total_size)) return frame->total_size; - HOST_WIDE_INT min_first_step = frame->total_size - frame->fp_sp_offset; - HOST_WIDE_INT max_first_step = IMM_REACH / 2 - PREFERRED_STACK_BOUNDARY / 8; - HOST_WIDE_INT min_second_step = frame->total_size - max_first_step; + HOST_WIDE_INT min_first_step = + RISCV_STACK_ALIGN (frame->total_size - frame->fp_sp_offset); + HOST_WIDE_INT max_first_step = + ROUND_DOWN (IMM_REACH / 2 - PREFERRED_STACK_BOUNDARY / 8, + PREFERRED_STACK_BOUNDARY / 8); + HOST_WIDE_INT min_second_step = + RISCV_STACK_ALIGN (frame->total_size - max_first_step); gcc_assert (min_first_step <= max_first_step); /* As an optimization, use the least-significant bits of the total frame -- 2.11.2
Hi all: I've hit a bug when running gcc testsuite with gc trunk on our internal simulator, C extension may generate non-aligned stack in some program point. Verified with gcc testsuite on rv32imac/rv32ima elf. Fail case: riscv32-elf-gcc -march=rv32imac gcc/testsuite/gcc.dg/graph ite/interchange-6.c -O2 -ffast-math -floop-nest-opt imize -o - -S ... .type main, @function main: li t1,-81920 addi sp,sp,-36 # <-- stack not aligned here! ... gcc/ChangeLog: 2018-04-18 Kito Cheng <kito.cheng@gmail.com> * config/riscv/riscv.c (riscv_first_stack_step): Round up min step and round down max step to make sure stack always aligned.