On 2/28/24 05:23, Kito Cheng wrote:
atomic_compare_and_swapsi will use lr.w and sc.w to do the atomic operation on
RV64, however lr.w is doing sign extend to DI and compare instruction only have
DI mode on RV64, so the expected value should be sign extend before compare as
well, so that we can get right compare result.
gcc/ChangeLog:
PR target/114130
* config/riscv/sync.md (atomic_compare_and_swap<mode>): Sign
extend the expected value if needed.
gcc/testsuite/ChangeLog:
* gcc.target/riscv/pr114130.c: New.
Nearly rejected this as I think the description was a bit ambiguous and
I thought you were extending the result of the lr.w. But it's actually
the other value you're ensuring gets properly extended.
OK.
Jeff
