Re: [PATCH] RISC-V: Use scratch reg for Rd ,so that src/rs2 is not clobbered for Store-Conditional.

[Jeff Law]

On 6/11/25 2:47 AM, Umesh Kalappa wrote:
gcc/ChangeLog:

         * config/riscv/sync.md (lrsc_atomic_exchange<mode>):
         Use the scratch reg for rd.

gcc/testsuite/ChangeLog:

         * gcc.target/riscv/zalrsc.c: New test.
I was about to push this to the trunk when I realized the test isn't 
really all that useful.

The net of this change is we get to drop the unnecessary mv.  But the 
test just verifies that we have a lr/sc pair, which was true both before 
and after this change.

Is it possible to improve the test such that it fails without this 
change and passes with this change?

Thanks,
jeff