diff --git a/llvm/include/llvm/Analysis/TargetTransformInfo.h b/llvm/include/llvm/Analysis/TargetTransformInfo.h
--- a/llvm/include/llvm/Analysis/TargetTransformInfo.h
+++ b/llvm/include/llvm/Analysis/TargetTransformInfo.h
@@ -853,6 +853,14 @@
   /// prefetching is performed.
   unsigned getMaxPrefetchIterationsAhead() const;
 
+  /// \return the number of write-combining buffers. A write-combining buffer is
+  /// a per-core resource used for collecting writes to a particular cache line
+  /// before further processing those writes using other parts of the memory
+  /// subsystem.  Knowledge of the number of write-combining buffers available
+  /// can help the optimizer manage those resources, for example fissioning
+  /// loops to avoid oversubscribing write-combining buffers.
+  unsigned getNumWriteCombiningBuffers() const;
+
   /// \return The maximum interleave factor that any transform should try to
   /// perform for this target. This number depends on the level of parallelism
   /// and the number of execution units in the CPU.
@@ -1272,6 +1280,9 @@
   /// prefetching is performed.
   virtual unsigned getMaxPrefetchIterationsAhead() const = 0;
 
+  /// \return the number of write-combining buffers.
+  virtual unsigned getNumWriteCombiningBuffers() const = 0;
+
   virtual unsigned getMaxInterleaveFactor(unsigned VF) = 0;
   virtual unsigned
   getArithmeticInstrCost(unsigned Opcode, Type *Ty, OperandValueKind Opd1Info,
@@ -1652,6 +1663,11 @@
     return Impl.getMaxPrefetchIterationsAhead();
   }
 
+  /// Return the number of write-combining buffers.
+  unsigned getNumWriteCombiningBuffers() const override {
+    return Impl.getNumWriteCombiningBuffers();
+  }
+
   unsigned getMaxInterleaveFactor(unsigned VF) override {
     return Impl.getMaxInterleaveFactor(VF);
   }
diff --git a/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h b/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
--- a/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
+++ b/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
@@ -371,6 +371,11 @@
     return false;
   }
 
+  /// Return the default number of write-combining buffers.
+  unsigned getNumWriteCombiningBuffers() const {
+    return 0;
+  }
+
   unsigned getMaxInterleaveFactor(unsigned VF) { return 1; }
 
   unsigned getArithmeticInstrCost(unsigned Opcode, Type *Ty,
diff --git a/llvm/include/llvm/CodeGen/BasicTTIImpl.h b/llvm/include/llvm/CodeGen/BasicTTIImpl.h
--- a/llvm/include/llvm/CodeGen/BasicTTIImpl.h
+++ b/llvm/include/llvm/CodeGen/BasicTTIImpl.h
@@ -543,6 +543,11 @@
     return getST()->getMaxPrefetchIterationsAhead();
   }
 
+  /// Return the number of write-combining buffers.
+  unsigned getNumWriteCombiningBuffers() const {
+    return getST()->getNumWriteCombiningBuffers();
+  }
+
   /// @}
 
   /// \name Vector TTI Implementations
diff --git a/llvm/include/llvm/MC/MCSubtargetInfo.h b/llvm/include/llvm/MC/MCSubtargetInfo.h
--- a/llvm/include/llvm/MC/MCSubtargetInfo.h
+++ b/llvm/include/llvm/MC/MCSubtargetInfo.h
@@ -267,6 +267,9 @@
   /// prefetching.
   ///
   virtual unsigned getMinPrefetchStride() const;
+
+  /// Return the number of write-combining buffers.
+  virtual unsigned getNumWriteCombiningBuffers() const;
 };
 
 } // end namespace llvm
diff --git a/llvm/lib/Analysis/TargetTransformInfo.cpp b/llvm/lib/Analysis/TargetTransformInfo.cpp
--- a/llvm/lib/Analysis/TargetTransformInfo.cpp
+++ b/llvm/lib/Analysis/TargetTransformInfo.cpp
@@ -546,6 +546,10 @@
   return TTIImpl->getMaxPrefetchIterationsAhead();
 }
 
+unsigned TargetTransformInfo::getNumWriteCombiningBuffers() const {
+  return TTIImpl->getNumWriteCombiningBuffers();
+}
+
 unsigned TargetTransformInfo::getMaxInterleaveFactor(unsigned VF) const {
   return TTIImpl->getMaxInterleaveFactor(VF);
 }
diff --git a/llvm/lib/MC/MCSubtargetInfo.cpp b/llvm/lib/MC/MCSubtargetInfo.cpp
--- a/llvm/lib/MC/MCSubtargetInfo.cpp
+++ b/llvm/lib/MC/MCSubtargetInfo.cpp
@@ -340,3 +340,7 @@
 unsigned MCSubtargetInfo::getMinPrefetchStride() const {
   return 1;
 }
+
+unsigned MCSubtargetInfo::getNumWriteCombiningBuffers() const {
+  return 0;
+}