Add element atomic memset intrinsic

Summary: Continuing the work from https://reviews.llvm.org/D33240, this change introduces an element unordered-atomic memset intrinsic. This intrinsic is essentially memset with the implementation requirement that all stores used for the assignment are done with unordered-atomic stores of a given element size.

Reviewers: eli.friedman, reames, mkazantsev, skatkov

Reviewed By: reames

Subscribers: jfb, dschuff, sbc100, jgravelle-google, aheejin, efriedma, llvm-commits

Differential Revision: https://reviews.llvm.org/D34885

llvm-svn: 307854

1 files changed, 39 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index da494a55855..28038484345 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -5032,6 +5032,45 @@ SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I, unsigned Intrinsic) {
     DAG.setRoot(CallResult.second);
     return nullptr;
   }
+  case Intrinsic::memset_element_unordered_atomic: {
+    auto &MI = cast<ElementUnorderedAtomicMemSetInst>(I);
+    SDValue Dst = getValue(MI.getRawDest());
+    SDValue Val = getValue(MI.getValue());
+    SDValue Length = getValue(MI.getLength());
+
+    // Emit a library call.
+    TargetLowering::ArgListTy Args;
+    TargetLowering::ArgListEntry Entry;
+    Entry.Ty = DAG.getDataLayout().getIntPtrType(*DAG.getContext());
+    Entry.Node = Dst;
+    Args.push_back(Entry);
+
+    Entry.Ty = Type::getInt8Ty(*DAG.getContext());
+    Entry.Node = Val;
+    Args.push_back(Entry);
+
+    Entry.Ty = MI.getLength()->getType();
+    Entry.Node = Length;
+    Args.push_back(Entry);
+
+    uint64_t ElementSizeConstant = MI.getElementSizeInBytes();
+    RTLIB::Libcall LibraryCall =
+        RTLIB::getMEMSET_ELEMENT_UNORDERED_ATOMIC(ElementSizeConstant);
+    if (LibraryCall == RTLIB::UNKNOWN_LIBCALL)
+      report_fatal_error("Unsupported element size");
+
+    TargetLowering::CallLoweringInfo CLI(DAG);
+    CLI.setDebugLoc(sdl).setChain(getRoot()).setLibCallee(
+        TLI.getLibcallCallingConv(LibraryCall),
+        Type::getVoidTy(*DAG.getContext()),
+        DAG.getExternalSymbol(TLI.getLibcallName(LibraryCall),
+                              TLI.getPointerTy(DAG.getDataLayout())),
+        std::move(Args));
+
+    std::pair<SDValue, SDValue> CallResult = TLI.LowerCallTo(CLI);
+    DAG.setRoot(CallResult.second);
+    return nullptr;
+  }
   case Intrinsic::dbg_declare: {
     const DbgDeclareInst &DI = cast<DbgDeclareInst>(I);
     DILocalVariable *Variable = DI.getVariable();