[PATCH] D111617: [RISCV] Lazily add RVV C intrinsics.

[Roger Ferrer Ibanez via Phabricator via llvm-commits]

rogfer01 added inline comments.


================
Comment at: clang/lib/Sema/SemaLookup.cpp:923
+
+  const RVVIntrinsicInfo *Intrinsic = std::find_if(
+      std::begin(RVVIntrinsicInfos), std::end(RVVIntrinsicInfos),
----------------
Not for this patch: I think this table may be a bit large so all lookups (including those that will fail) will be slower after a `#pragma riscv intrinsic vector` is found.

Filtering them as fast as possible (looking at the spec shows that currently all RVV intrinsics start with `v`) or using some hash table (if too difficult to build at compile time we could build it the first time we get here?) might be something we want to do.


================
Comment at: clang/lib/Sema/SemaLookup.cpp:1011
 
+      if (PP.getPredefines() == "#define __riscv_pragma_vector_intrinsics") {
+        const TargetInfo &TI = Context.getTargetInfo();
----------------
This seems a bit fragile if there are more predefines than just this one. I understand the intent is to avoid looking up the RVV builtin every time, only do that if we have found the pragma, right?

Several pragma handlers receive a reference to `Sema` (in an object called `Action` or `Actions`) and then they notify `Sema` (via a member function that would have to be added to it) about having parsed the pragma. That could be used to set some flag to true in `Sema` itself and also emit diagnostics if we want (e.g. what if the pragma is used twice? can it be used anywhere?).

Do you think this would be workable?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D111617/new/

https://reviews.llvm.org/D111617