[PATCH] D52961: [RISCV] Introduce the RISCVMatInt::generateInstSeq helper
Sameer AbuAsal via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Wed Oct 10 15:30:07 PDT 2018
sabuasal added a comment.
In https://reviews.llvm.org/D52961#1258464, @asb wrote:
> In https://reviews.llvm.org/D52961#1258446, @sabuasal wrote:
>
> > The helper makes it clear to follow. Thanks!
> >
> > I am just not sure why you did the change to prefer add to addiw when for 64bit? is addi faster than addiw?
>
>
> No real reason to prefer one or the other when they're semantically identical. It's mostly to be closer to gas/gcc which uses addi at least for the isInt<12> case.
I see. makes sense.
> $echo "li x11, -2048" | llvm-mc -filetype=obj -triple=riscv64 -o ./a.out && riscv64-unknown-linux-gnu-objdump -dr -M no-aliases ./a.out
>
> ./a.out: file format elf64-littleriscv
>
> Disassembly of section .text:
>
> 0000000000000000 <.text>:
>
> 0: 8000059b addiw a1,zero,-2048
>
> $echo "li x11, -2048" | riscv64-unknown-linux-gnu-as -o ./a.out && riscv64-unknown-linux-gnu-objdump -dr -M no-aliases ./a.out
>
> ./a.out: file format elf64-littleriscv
>
> Disassembly of section .text:
>
> 0000000000000000 <.text>:
>
> 0: 80000593 addi a1,zero,-2048
https://reviews.llvm.org/D52961
More information about the llvm-commits
mailing list