Stack boundary for RV32E about riscv-elf-psabi-doc HOT 6 OPEN

Another alternative: keep the current ABI, and have the compiler realign stack frames when doubles are stack-allocated. This adds two instructions (6 bytes of code) to each function that stack-allocates doubles, but retains the more compact stack frames.

Regardless, we should keep the current ABI as-is, and I propose we hold off on creating any new RV32EFD ABI until demand/applications materialize.

from riscv-elf-psabi-doc.

GCC can handle that correctly, so I guess the only thing we need to care is we'd better write comment and give a sample code on ABI document?

from riscv-elf-psabi-doc.

Dynamically aligning the stack is a tricky problem. The x86 port has code to do this, and we seem to find problems in it with every gcc release. I'd rather not go that direction if we can avoid it.

from riscv-elf-psabi-doc.

Isn't stack realignment logic already required even for the standard ABIs due to __int128_t and long double?

from riscv-elf-psabi-doc.

Default stack alignment for standard ABIs is 16 bytes, and nothing requires more than 16 byte alignment, so no, we don't need stack realignment and currently have no support for that in the gcc RISC-V port.

from riscv-elf-psabi-doc.

I misremembered, sorry for the noise. We do use 16-byte stack alignment in LLVM too.

from riscv-elf-psabi-doc.