Re: [PATCH] riscv: Fix insn cost calculation

[Jeff Law <jeffreyalaw@gmail.com>]

On 6/5/23 22:51, Dimitar Dimitrov wrote:
> When building riscv32-none-elf with "--enable-checking=yes,rtl", the
> following ICE is observed:
> 
>    cc1: internal compiler error: RTL check: expected code 'const_int', have 'const_double' in riscv_const_insns, at config/riscv/riscv.cc:1313
>    0x843c4d rtl_check_failed_code1(rtx_def const*, rtx_code, char const*, int, char const*)
>            /mnt/nvme/dinux/local-workspace/gcc/gcc/rtl.cc:916
>    0x8eab61 riscv_const_insns(rtx_def*)
>            /mnt/nvme/dinux/local-workspace/gcc/gcc/config/riscv/riscv.cc:1313
>    0x15443bb riscv_legitimate_constant_p
>            /mnt/nvme/dinux/local-workspace/gcc/gcc/config/riscv/riscv.cc:826
>    0xdd3c71 emit_move_insn(rtx_def*, rtx_def*)
>            /mnt/nvme/dinux/local-workspace/gcc/gcc/expr.cc:4310
>    0x15f28e5 run_const_vector_selftests
>            /mnt/nvme/dinux/local-workspace/gcc/gcc/config/riscv/riscv-selftests.cc:285
>    0x15f37bd selftest::riscv_run_selftests()
>            /mnt/nvme/dinux/local-workspace/gcc/gcc/config/riscv/riscv-selftests.cc:364
>    0x1f6fba9 selftest::run_tests()
>            /mnt/nvme/dinux/local-workspace/gcc/gcc/selftest-run-tests.cc:111
>    0x11d1f39 toplev::run_self_tests()
>            /mnt/nvme/dinux/local-workspace/gcc/gcc/toplev.cc:2185
> 
> Fix by following the spirit of the adjacent comment, and using the
> dedicated riscv_const_insns() function to calculate cost for loading a
> constant element.  Infinite recursion is not possible because the first
> invocation is on a CONST_VECTOR, whereas the second is on a single
> element of the vector (e.g. CONST_INT or CONST_DOUBLE).
> 
> Regression tested for riscv32-none-elf. No changes in gcc.sum and
> g++.sum.  I don't have setup to test riscv64.
I think most folks are using QEMU to test.  Though I think most are 
doing it in a rv64 environment.

> 
> gcc/ChangeLog:
> 
> 	* config/riscv/riscv.cc (riscv_const_insns): Recursively call
> 	for constant element of a vector.
OK for the trunk.  I don't think this code is in gcc-13, but also OK as 
a backport if I'm wrong and it is in gcc-13.

jeff