On Wed, 28 Feb 2024 06:57:53 PST (-0800), jeffreya...@gmail.com wrote:
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.
I had the same response, but after reading it I'm not quite sure how to say it better.
OK.
I was looking at the code to try and ask if we have the same bug for the short inline CAS routines, but I've got to run to some meetings...
Jeff
