Index: lib/Transforms/InstCombine/InstCombineInternal.h
===================================================================
--- lib/Transforms/InstCombine/InstCombineInternal.h
+++ lib/Transforms/InstCombine/InstCombineInternal.h
@@ -74,6 +74,27 @@
   return isa<Constant>(V) ? (isa<UndefValue>(V) ? 0 : 1) : 2;
 }
 
+/// Predicate canonicalization attempts to reduce the number of patterns that
+/// need to be matched by other transforms. For example, we may swap the
+/// operands of a conditional branch or select to create a compare with a
+/// canonical (inverted) predicate which can then be matched with other values.
+static inline bool isCanonicalPredicate(CmpInst::Predicate Pred) {
+  switch (Pred) {
+  case CmpInst::ICMP_NE:
+  case CmpInst::ICMP_ULE:
+  case CmpInst::ICMP_SLE:
+  case CmpInst::ICMP_UGE:
+  case CmpInst::ICMP_SGE:
+  // TODO: There are 16 FCMP predicates. Should others be (not) canonical?
+  case CmpInst::FCMP_ONE:
+  case CmpInst::FCMP_OLE:
+  case CmpInst::FCMP_OGE:
+    return false;
+  default:
+    return true;
+  }
+}
+
 /// \brief Add one to a Constant
 static inline Constant *AddOne(Constant *C) {
   return ConstantExpr::getAdd(C, ConstantInt::get(C->getType(), 1));
Index: lib/Transforms/InstCombine/InstructionCombining.cpp
===================================================================
--- lib/Transforms/InstCombine/InstructionCombining.cpp
+++ lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -2210,37 +2210,17 @@
     return &BI;
   }
 
-  // Canonicalize fcmp_one -> fcmp_oeq
-  FCmpInst::Predicate FPred; Value *Y;
-  if (match(&BI, m_Br(m_OneUse(m_FCmp(FPred, m_Value(X), m_Value(Y))),
-                      TrueDest, FalseDest))) {
-    // TODO: Why are we only transforming these 3 predicates?
-    if (FPred == FCmpInst::FCMP_ONE || FPred == FCmpInst::FCMP_OLE ||
-        FPred == FCmpInst::FCMP_OGE) {
-      FCmpInst *Cond = cast<FCmpInst>(BI.getCondition());
-      Cond->setPredicate(FCmpInst::getInversePredicate(FPred));
-
-      // Swap Destinations and condition.
-      BI.swapSuccessors();
-      Worklist.Add(Cond);
-      return &BI;
-    }
-  }
-
-  // Canonicalize icmp_ne -> icmp_eq
-  ICmpInst::Predicate IPred;
-  if (match(&BI, m_Br(m_OneUse(m_ICmp(IPred, m_Value(X), m_Value(Y))),
-                      TrueDest, FalseDest))) {
-    if (IPred == ICmpInst::ICMP_NE  || IPred == ICmpInst::ICMP_ULE ||
-        IPred == ICmpInst::ICMP_SLE || IPred == ICmpInst::ICMP_UGE ||
-        IPred == ICmpInst::ICMP_SGE) {
-      ICmpInst *Cond = cast<ICmpInst>(BI.getCondition());
-      Cond->setPredicate(ICmpInst::getInversePredicate(IPred));
-      // Swap Destinations and condition.
-      BI.swapSuccessors();
-      Worklist.Add(Cond);
-      return &BI;
-    }
+  // Canonicalize, for example, icmp_ne -> icmp_eq or fcmp_one -> fcmp_oeq.
+  CmpInst::Predicate Pred;
+  if (match(&BI, m_Br(m_OneUse(m_Cmp(Pred, m_Value(), m_Value())), TrueDest,
+                      FalseDest)) &&
+      !isCanonicalPredicate(Pred)) {
+    // Swap destinations and condition.
+    CmpInst *Cond = cast<CmpInst>(BI.getCondition());
+    Cond->setPredicate(CmpInst::getInversePredicate(Pred));
+    BI.swapSuccessors();
+    Worklist.Add(Cond);
+    return &BI;
   }
 
   return nullptr;