[clang] [clang][SPIR-V] Always add convervence intrinsics (PR #88918)

[Chris B via cfe-commits]

Nathan =?utf-8?q?Gauër?= <brioche at google.com>,
Nathan =?utf-8?q?Gauër?= <brioche at google.com>
Message-ID:
In-Reply-To: <llvm.org/llvm/llvm-project/pull/88918 at github.com>


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@@ -3101,3 +3130,68 @@ CodeGenFunction::GenerateCapturedStmtFunction(const CapturedStmt &S) {
 
   return F;
 }
+
+namespace {
+// Returns the first convergence entry/loop/anchor instruction found in |BB|.
+// std::nullptr otherwise.
+llvm::IntrinsicInst *getConvergenceToken(llvm::BasicBlock *BB) {
+  for (auto &I : *BB) {
+    auto *II = dyn_cast<llvm::IntrinsicInst>(&I);
+    if (II && llvm::isConvergenceControlIntrinsic(II->getIntrinsicID()))
+      return II;
+  }
+  return nullptr;
+}
+
+} // namespace
+
+llvm::CallBase *
+CodeGenFunction::addConvergenceControlToken(llvm::CallBase *Input,
+                                            llvm::Value *ParentToken) {
+  llvm::Value *bundleArgs[] = {ParentToken};
+  llvm::OperandBundleDef OB("convergencectrl", bundleArgs);
+  auto Output = llvm::CallBase::addOperandBundle(
+      Input, llvm::LLVMContext::OB_convergencectrl, OB, Input);
+  Input->replaceAllUsesWith(Output);
+  Input->eraseFromParent();
+  return Output;
+}
+
+llvm::IntrinsicInst *
+CodeGenFunction::emitConvergenceLoopToken(llvm::BasicBlock *BB,
+                                          llvm::Value *ParentToken) {
+  CGBuilderTy::InsertPoint IP = Builder.saveIP();
+
+  if (BB->empty())
+    Builder.SetInsertPoint(BB);
+  else
+    Builder.SetInsertPoint(&BB->front());
+
+  auto CB = Builder.CreateIntrinsic(
+      llvm::Intrinsic::experimental_convergence_loop, {}, {});
+  Builder.restoreIP(IP);
+
+  auto I = addConvergenceControlToken(CB, ParentToken);
----------------
llvm-beanz wrote:

I'm pretty sure that some of this is just code that you moved from CGBuiltin.cpp, but we probably should change the gratuitous use of `auto`. LLVM's conventions only use `auto` when it improves readability (see: https://llvm.org/docs/CodingStandards.html#use-auto-type-deduction-to-make-code-more-readable).

In quite a few of these cases the explicit type would be much more readable.

https://github.com/llvm/llvm-project/pull/88918