Re: [PATCH V2] RISC-V: decouple stack allocation for rv32e w/o save-restore.

[Jeff Law via Gcc-patches]

On 4/29/23 04:59, Fei Gao wrote:

Currently in rv32e, stack allocation for GPR callee-saved registers is
always 12 bytes w/o save-restore. Actually, for the case without save-restore,
less stack memory can be reserved. This patch decouples stack allocation for
rv32e w/o save-restore and makes riscv_compute_frame_info more readable.

output of testcase rv32e_stack.c
before patch:
        addi    sp,sp,-16
        sw      ra,12(sp)
        call    getInt
        sw      a0,0(sp)
        lw      a0,0(sp)
        call    PrintInts
        lw      a5,0(sp)
        mv      a0,a5
        lw      ra,12(sp)
        addi    sp,sp,16
        jr      ra

after patch:
        addi    sp,sp,-8
        sw      ra,4(sp)
        call    getInt
        sw      a0,0(sp)
        lw      a0,0(sp)
        call    PrintInts
        lw      a5,0(sp)
        mv      a0,a5
        lw      ra,4(sp)
        addi    sp,sp,8
        jr      ra


gcc/ChangeLog:

         * config/riscv/riscv.cc (riscv_avoid_save_libcall): helper function 
for riscv_use_save_libcall.
         (riscv_use_save_libcall): call riscv_avoid_save_libcall.
         (riscv_compute_frame_info): restructure to decouple stack allocation 
for rv32e w/o save-restore.

gcc/testsuite/ChangeLog:

         * gcc.target/riscv/rv32e_stack.c: New test.

Thanks.  I rewrapped the ChangeLog and pushed this to the trunk.

jeff