On 10/31/23 17:41, Palmer Dabbelt wrote:
On Tue, 31 Oct 2023 16:18:35 PDT (-0700), jeffreya...@gmail.com wrote:
On 10/31/23 12:35, Vineet Gupta wrote:
riscv_promote_function_mode doesn't promote a SI to DI for libcalls
case.
The fix is what generic promote_mode () in explow.cc does. I really
don't understand why the old code didn't work, but stepping thru the
debugger shows old code didn't and fixed does.
This showed up when testing Ajit's REE ABI extension series which probes
the ABI (using a NULL tree type) and ends up hitting the libcall code
path.
[Usual caveat, I'll wait for Pre-commit CI to run the tests and report]
gcc/ChangeLog:
* config/riscv/riscv.cc (riscv_promote_function_mode): Fix mode
returned for libcall case.
Hmm. There may be dragons in here. I'll need to find and review an old
conversation in this space (libcalls and argument promotions).
We also have a non-orthogonality in the ABI sign extension rules between
SI and DI, a few of us were talking about it on the internal slack
(though the specifics were for a different patch, Vineet has a few in
flight).
So the old issue I was thinking of really only affects targets that push
arguments on the stack and when a sub-word push actually allocates a
full word on the stack (m68k, but !coldfire, h8 and probably others of
that era).
Point being, those issues don't apply here.
jeff
