Explicitly backup and restore for each intrinsic just the same as we did for CALL in this patch.
I can't have the data to prove how good we use LCM/PRE of mode switching but I trust it. Since the the LCM/PRE is the key optimization method of VSETVL PASS which is doing good job on VSETVL instruction optimizations. I don't we should give up LCM/PRE chance then just backup and restore for each intrinsic bindly. juzhe.zh...@rivai.ai From: Robin Dapp Date: 2023-07-26 21:46 To: juzhe.zhong; Li, Pan2 CC: rdapp.gcc; Kito Cheng; gcc-patches@gcc.gnu.org; Wang, Yanzhang Subject: Re: [PATCH v7] RISC-V: Support CALL for RVV floating-point dynamic rounding > current llvm didn't do any pre optimization. They always > backup+restore for each rounding mode intrinsic I see. There is still the option of lazily restoring the (entry) FRM before a function call but not read the FRM after every call. Do we have any data on how good or bad the mode-switching LCM works when we explicitly backup and restore for each intrinsic? Regards Robin
