[clang] [llvm] [MC/DC][Coverage] Loosen the limit of NumConds from 6 (PR #82448)

[NAKAMURA Takumi via cfe-commits]

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@@ -1201,19 +1197,22 @@ void CodeGenPGO::emitMCDCCondBitmapUpdate(CGBuilderTy &Builder, const Expr *S,
   // Extract the ID of the condition we are setting in the bitmap.
   const auto &Branch = BranchStateIter->second;
   assert(Branch.ID >= 0 && "Condition has no ID!");
+  assert(Branch.DecisionStmt);
 
-  auto *I8PtrTy = llvm::PointerType::getUnqual(CGM.getLLVMContext());
+  // Cancel the emission if the Decision is erased after the allocation.
+  const auto DecisionIter =
+      RegionMCDCState->DecisionByStmt.find(Branch.DecisionStmt);
+  if (DecisionIter == RegionMCDCState->DecisionByStmt.end())
+    return;
 
-  // Emit intrinsic that updates a dedicated temporary value on the stack after
-  // a condition is evaluated. After the set of conditions has been updated,
-  // the resulting value is used to update the boolean expression's bitmap.
-  llvm::Value *Args[5] = {llvm::ConstantExpr::getBitCast(FuncNameVar, I8PtrTy),
-                          Builder.getInt64(FunctionHash),
-                          Builder.getInt32(Branch.ID),
-                          MCDCCondBitmapAddr.getPointer(), Val};
-  Builder.CreateCall(
-      CGM.getIntrinsic(llvm::Intrinsic::instrprof_mcdc_condbitmap_update),
-      Args);
+  const auto &TVIdxs = DecisionIter->second.Indices[Branch.ID];
+
+  auto *CurTV = Builder.CreateLoad(MCDCCondBitmapAddr,
+                                   "mcdc." + Twine(Branch.ID + 1) + ".cur");
+  auto *NewTV = Builder.CreateAdd(CurTV, Builder.getInt32(TVIdxs[true]));
+  NewTV = Builder.CreateSelect(
+      Val, NewTV, Builder.CreateAdd(CurTV, Builder.getInt32(TVIdxs[false])));
+  Builder.CreateStore(NewTV, MCDCCondBitmapAddr);
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chapuni wrote:

I don't think it wouldn't make sense to make this as the intrinsic, because this doesn't operate special operations. I'd like to create cleanups later to prune `condbitmap_update` since pruning is not the prerequisite of this change.

In contrast, I think `tvbitmap` may be left, because it could emit atomic operations as options.

https://github.com/llvm/llvm-project/pull/82448