[Hexagon] Make memcpy lowering thread-safe

This removes an unpleasant hack involving a global variable for special
lowering of certain memcpy calls. These are now lowered as intended in
EmitTargetCodeForMemcpy in the same way that other targets do it.

llvm-svn: 255785

1 files changed, 37 insertions, 13 deletions

diff --git a/llvm/lib/Target/Hexagon/HexagonSelectionDAGInfo.cpp b/llvm/lib/Target/Hexagon/HexagonSelectionDAGInfo.cpp
index 276cc69eed0..239dbda8f27 100644
--- a/llvm/lib/Target/Hexagon/HexagonSelectionDAGInfo.cpp
+++ b/llvm/lib/Target/Hexagon/HexagonSelectionDAGInfo.cpp
@@ -12,12 +12,11 @@
 //===----------------------------------------------------------------------===//
 
 #include "HexagonTargetMachine.h"
+#include "llvm/CodeGen/SelectionDAG.h"
 using namespace llvm;
 
 #define DEBUG_TYPE "hexagon-selectiondag-info"
 
-bool llvm::flag_aligned_memcpy;
-
 SDValue
 HexagonSelectionDAGInfo::
 EmitTargetCodeForMemcpy(SelectionDAG &DAG, SDLoc dl, SDValue Chain,
@@ -25,15 +24,40 @@ EmitTargetCodeForMemcpy(SelectionDAG &DAG, SDLoc dl, SDValue Chain,
                         bool isVolatile, bool AlwaysInline,
                         MachinePointerInfo DstPtrInfo,
                         MachinePointerInfo SrcPtrInfo) const {
-  flag_aligned_memcpy = false;
-  if ((Align & 0x3) == 0) {
-    ConstantSDNode *ConstantSize = dyn_cast<ConstantSDNode>(Size);
-    if (ConstantSize) {
-      uint64_t SizeVal = ConstantSize->getZExtValue();
-      if ((SizeVal > 32) && ((SizeVal % 8) == 0))
-        flag_aligned_memcpy = true;
-    }
-  }
-
-  return SDValue();
+  ConstantSDNode *ConstantSize = dyn_cast<ConstantSDNode>(Size);
+  if (AlwaysInline || (Align & 0x3) != 0 || !ConstantSize)
+    return SDValue();
+
+  uint64_t SizeVal = ConstantSize->getZExtValue();
+  if (SizeVal < 32 || (SizeVal % 8) != 0)
+    return SDValue();
+
+  // Special case aligned memcpys with size >= 32 bytes and a multiple of 8.
+  //
+  const TargetLowering &TLI = *DAG.getSubtarget().getTargetLowering();
+  TargetLowering::ArgListTy Args;
+  TargetLowering::ArgListEntry Entry;
+  Entry.Ty = DAG.getDataLayout().getIntPtrType(*DAG.getContext());
+  Entry.Node = Dst;
+  Args.push_back(Entry);
+  Entry.Node = Src;
+  Args.push_back(Entry);
+  Entry.Node = Size;
+  Args.push_back(Entry);
+
+  const char *SpecialMemcpyName =
+      "__hexagon_memcpy_likely_aligned_min32bytes_mult8bytes";
+
+  TargetLowering::CallLoweringInfo CLI(DAG);
+  CLI.setDebugLoc(dl)
+      .setChain(Chain)
+      .setCallee(TLI.getLibcallCallingConv(RTLIB::MEMCPY),
+                 Type::getVoidTy(*DAG.getContext()),
+                 DAG.getTargetExternalSymbol(
+                     SpecialMemcpyName, TLI.getPointerTy(DAG.getDataLayout())),
+                 std::move(Args), 0)
+      .setDiscardResult();
+
+  std::pair<SDValue, SDValue> CallResult = TLI.LowerCallTo(CLI);
+  return CallResult.second;
 }