Re: [PATCH] RISC-V: Fix out of range memory access of machine mode table

[Jeff Law <jeffreyalaw@gmail.com>]

On 6/21/23 18:19, Li, Pan2 wrote:
> Hi there,
> 
> I try to verify the offloading following below doc.
> 
> https://gcc.gnu.org/wiki/Offloading#How_to_build_an_offloading-enabled_GCC
> 
> with some steps:
> 
> 1. Build nvptx-tools.
> 2. Symbol link nvptx-newlib to gcc source code.
> 3. Build the Nividia PTX accel compiler.
> 4. Build the host compiler with nvptx as offload target, but I don't have the GPU, then drop the --with-cuda-driver=xxx option.
> 5. Run command for building, aka ./nvptx-tools/usr/local/bin/gcc -O0 -fopenmp test.c -o test.elf.
> 
> The building complete successfully, but looks I cannot run it without GPU, and I am not very sure this is good enough for validation or not.
If you don't have a suitable GPU for offloading, you could instead just 
compare the offloaded binary before/after your change.  I would expect 
them to be 100% identical.

If we take that route for verification, I think the question turns into 
how to do that for the testsuite.  ie, I think Jakub wants to verify 
that check-target-libgomp still passes when offloading is enabled.  I 
don't think there's an easy way to capture the resulting binaries for 
comparison purposes.  But that's what I'd suggest given the lack of a 
suitable GPU for testing.  So you might need to hack up the libgomp 
testsuite's .exp files to capture the binaries.

Before going to those extremes, I would suggest verifying that you do in 
fact get identical binaries before/after your change on a simple 
offloading test.



jeff