tentzen added a comment. In D77936#1976938 <https://reviews.llvm.org/D77936#1976938>, @efriedma wrote:
> Instead of asserting there are less than 256 cleanup destinations, can you > emit an icmp against zero, or something like that? I did consider that. but it splits the block and induces one compare and one branch in _try exit sequence for something that will not happen in RWC. And it's hard for Optimizer to deal with it. Optimizer can probably can tail-duplicate each path at the expense of code size which I don't think LLVM would do today. Do you really think it's worth to split the block here? thanks ================ Comment at: clang/lib/CodeGen/CGException.cpp:1651 + llvm::Value* Load = CGF.Builder.CreateLoad(Addr, "cleanup.dest"); + IsForEH = CGF.Builder.CreateTrunc(Load, CGM.Int8Ty); + } ---------------- efriedma wrote: > Is just truncating the value really correct? What's the possible range of > values stored in getNormalCleanupDestSlot()? Good question! Usually the number in NormalCleanupDestSlot is single digit (or at most double-digit) , the totoal number of Jump Destinations (return/goto/break/continue/..) in the function. I thought about widening 1st arg from CHAR to unsigned, but dropped the idea as it seems unnecessary. Yes, someone can write a code to make more than 255 Jumps in a function, but it’s unlikely to happen in real world code. What do you think? I can go either way.. For sure, we can add an assert to catch it. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D77936/new/ https://reviews.llvm.org/D77936 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
