Index: include/llvm/IR/IRBuilder.h
===================================================================
--- include/llvm/IR/IRBuilder.h
+++ include/llvm/IR/IRBuilder.h
@@ -1577,12 +1577,16 @@
   }
 
   Value *CreateSelect(Value *C, Value *True, Value *False,
-                      const Twine &Name = "") {
+                      const Twine &Name = "", MDNode *ProfWeights = nullptr) {
     if (Constant *CC = dyn_cast<Constant>(C))
       if (Constant *TC = dyn_cast<Constant>(True))
         if (Constant *FC = dyn_cast<Constant>(False))
           return Insert(Folder.CreateSelect(CC, TC, FC), Name);
-    return Insert(SelectInst::Create(C, True, False), Name);
+
+    SelectInst *Sel = SelectInst::Create(C, True, False);
+    // TODO: "unpredictable" metadata can apply to a select too.
+    Sel->setMetadata(LLVMContext::MD_prof, ProfWeights);
+    return Insert(Sel, Name);
   }
 
   VAArgInst *CreateVAArg(Value *List, Type *Ty, const Twine &Name = "") {
Index: lib/Transforms/Utils/SimplifyCFG.cpp
===================================================================
--- lib/Transforms/Utils/SimplifyCFG.cpp
+++ lib/Transforms/Utils/SimplifyCFG.cpp
@@ -1935,7 +1935,8 @@
     Value *TrueVal  = PN->getIncomingValue(PN->getIncomingBlock(0) == IfFalse);
     Value *FalseVal = PN->getIncomingValue(PN->getIncomingBlock(0) == IfTrue);
 
-    Value *Select = Builder.CreateSelect(IfCond, TrueVal, FalseVal);
+    MDNode *MDN = InsertPt->getMetadata(LLVMContext::MD_prof);
+    Value *Select = Builder.CreateSelect(IfCond, TrueVal, FalseVal, "", MDN);
     PN->replaceAllUsesWith(Select);
     Select->takeName(PN);
     PN->eraseFromParent();
Index: test/Transforms/SimplifyCFG/preserve-branchweights.ll
===================================================================
--- test/Transforms/SimplifyCFG/preserve-branchweights.ll
+++ test/Transforms/SimplifyCFG/preserve-branchweights.ll
@@ -364,6 +364,35 @@
   ret void
 }
 
+; PR26636: The branch metadata should get propagated to the select.
+
+define i32 @FoldTwoEntryPHINode(i32 %x) #0 {
+entry:
+  %cmp = icmp sgt i32 %x, 4
+  br i1 %cmp, label %if.then, label %if.end, !prof !12
+
+if.then:
+  %add = add nsw i32 %x, 7
+  br label %return
+
+if.end:
+  %mul = mul nsw i32 %x, 17
+  br label %return
+
+return:
+  %retval.0 = phi i32 [ %add, %if.then ], [ %mul, %if.end ]
+  ret i32 %retval.0
+
+; CHECK-LABEL: @FoldTwoEntryPHINode(
+; CHECK-NEXT: entry:
+; CHECK-NEXT:  %cmp = icmp sgt i32 %x, 4
+; CHECK-NEXT:  %add = add nsw i32 %x, 7
+; CHECK-NEXT:  %mul = mul nsw i32 %x, 17
+; CHECK-NEXT:  %retval.0 = select i1 %cmp, i32 %add, i32 %mul, !prof !11
+; CHECK-NEXT:  ret i32 %retval.0
+}
+
+
 !0 = !{!"branch_weights", i32 3, i32 5}
 !1 = !{!"branch_weights", i32 1, i32 1}
 !2 = !{!"branch_weights", i32 1, i32 2}
@@ -376,6 +405,7 @@
 !9 = !{!"branch_weights", i32 7, i32 6}
 !10 = !{!"branch_weights", i32 672646, i32 21604207}
 !11 = !{!"branch_weights", i32 6960, i32 21597248}
+!12 = !{!"branch_weights", i32 6, i32 2000}
 
 ; CHECK: !0 = !{!"branch_weights", i32 5, i32 11}
 ; CHECK: !1 = !{!"branch_weights", i32 1, i32 5}
@@ -390,3 +420,4 @@
 ;; The false weight prints out as a negative integer here, but inside llvm, we
 ;; treat the weight as an unsigned integer.
 ; CHECK: !10 = !{!"branch_weights", i32 112017436, i32 -735157296}
+; CHECK: !11 = !{!"branch_weights", i32 6, i32 2000}