2 files changed, 22 insertions, 0 deletions
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 0b0fff739eb..f96eaf9cd43 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -92,6 +92,13 @@ static cl::opt<bool> MulConstantOptimization(
              "SHIFT, LEA, etc."),
     cl::Hidden);
 
+static cl::opt<bool> ExperimentalUnorderedISEL(
+    "x86-experimental-unordered-atomic-isel", cl::init(false),
+    cl::desc("Use LoadSDNode and StoreSDNode instead of "
+             "AtomicSDNode for unordered atomic loads and "
+             "stores respectively."),
+    cl::Hidden);
+
 /// Call this when the user attempts to do something unsupported, like
 /// returning a double without SSE2 enabled on x86_64. This is not fatal, unlike
 /// report_fatal_error, so calling code should attempt to recover without
@@ -26493,6 +26500,18 @@ X86TargetLowering::lowerIdempotentRMWIntoFencedLoad(AtomicRMWInst *AI) const {
   return Loaded;
 }
 
+bool X86TargetLowering::lowerAtomicStoreAsStoreSDNode(const StoreInst &SI) const {
+  if (!SI.isUnordered())
+    return false;
+  return ExperimentalUnorderedISEL;
+}
+bool X86TargetLowering::lowerAtomicLoadAsLoadSDNode(const LoadInst &LI) const {
+  if (!LI.isUnordered())
+    return false;
+  return ExperimentalUnorderedISEL;
+}
+
+
 /// Emit a locked operation on a stack location which does not change any
 /// memory location, but does involve a lock prefix.  Location is chosen to be
 /// a) very likely accessed only by a single thread to minimize cache traffic,
diff --git a/llvm/lib/Target/X86/X86ISelLowering.h b/llvm/lib/Target/X86/X86ISelLowering.h
index fbc9509f058..82e3b989ec5 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.h
+++ b/llvm/lib/Target/X86/X86ISelLowering.h
@@ -1388,6 +1388,9 @@ namespace llvm {
     LoadInst *
     lowerIdempotentRMWIntoFencedLoad(AtomicRMWInst *AI) const override;
 
+    bool lowerAtomicStoreAsStoreSDNode(const StoreInst &SI) const override;
+    bool lowerAtomicLoadAsLoadSDNode(const LoadInst &LI) const override;
+
     bool needsCmpXchgNb(Type *MemType) const;
 
     void SetupEntryBlockForSjLj(MachineInstr &MI, MachineBasicBlock *MBB,