Index: llvm/include/llvm/Bitcode/LLVMBitCodes.h
===================================================================
--- llvm/include/llvm/Bitcode/LLVMBitCodes.h
+++ llvm/include/llvm/Bitcode/LLVMBitCodes.h
@@ -587,6 +587,7 @@
   ATTR_KIND_SPECULATABLE = 53,
   ATTR_KIND_STRICT_FP = 54,
   ATTR_KIND_SANITIZE_HWADDRESS = 55,
+  ATTR_KIND_NO_CFG_SELECT_FORMATION = 56,
 };
 
 enum ComdatSelectionKindCodes {
Index: llvm/include/llvm/IR/Attributes.td
===================================================================
--- llvm/include/llvm/IR/Attributes.td
+++ llvm/include/llvm/IR/Attributes.td
@@ -82,6 +82,9 @@
 /// Function creates no aliases of pointer.
 def NoCapture : EnumAttr<"nocapture">;
 
+/// CFG simplification shouldn't convert control flow to selects.
+def NoCFGSelectFormation : EnumAttr<"no_cfg_select_formation">;
+
 /// Call cannot be duplicated.
 def NoDuplicate : EnumAttr<"noduplicate">;
 
Index: llvm/lib/AsmParser/LLLexer.cpp
===================================================================
--- llvm/lib/AsmParser/LLLexer.cpp
+++ llvm/lib/AsmParser/LLLexer.cpp
@@ -640,6 +640,7 @@
   KEYWORD(noalias);
   KEYWORD(nobuiltin);
   KEYWORD(nocapture);
+  KEYWORD(no_cfg_select_formation);
   KEYWORD(noduplicate);
   KEYWORD(noimplicitfloat);
   KEYWORD(noinline);
Index: llvm/lib/AsmParser/LLParser.cpp
===================================================================
--- llvm/lib/AsmParser/LLParser.cpp
+++ llvm/lib/AsmParser/LLParser.cpp
@@ -1124,6 +1124,8 @@
     case lltok::kw_minsize: B.addAttribute(Attribute::MinSize); break;
     case lltok::kw_naked: B.addAttribute(Attribute::Naked); break;
     case lltok::kw_nobuiltin: B.addAttribute(Attribute::NoBuiltin); break;
+    case lltok::kw_no_cfg_select_formation:
+      B.addAttribute(Attribute::NoCFGSelectFormation); break;
     case lltok::kw_noduplicate: B.addAttribute(Attribute::NoDuplicate); break;
     case lltok::kw_noimplicitfloat:
       B.addAttribute(Attribute::NoImplicitFloat); break;
@@ -1462,6 +1464,7 @@
     case lltok::kw_minsize:
     case lltok::kw_naked:
     case lltok::kw_nobuiltin:
+    case lltok::kw_no_cfg_select_formation:
     case lltok::kw_noduplicate:
     case lltok::kw_noimplicitfloat:
     case lltok::kw_noinline:
@@ -1555,6 +1558,7 @@
     case lltok::kw_minsize:
     case lltok::kw_naked:
     case lltok::kw_nobuiltin:
+    case lltok::kw_no_cfg_select_formation:
     case lltok::kw_noduplicate:
     case lltok::kw_noimplicitfloat:
     case lltok::kw_noinline:
Index: llvm/lib/AsmParser/LLToken.h
===================================================================
--- llvm/lib/AsmParser/LLToken.h
+++ llvm/lib/AsmParser/LLToken.h
@@ -191,6 +191,7 @@
   kw_noalias,
   kw_nobuiltin,
   kw_nocapture,
+  kw_no_cfg_select_formation,
   kw_noduplicate,
   kw_noimplicitfloat,
   kw_noinline,
Index: llvm/lib/Bitcode/Reader/BitcodeReader.cpp
===================================================================
--- llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -1160,6 +1160,7 @@
   case Attribute::Speculatable:    return 1ULL << 54;
   case Attribute::StrictFP:        return 1ULL << 55;
   case Attribute::SanitizeHWAddress: return 1ULL << 56;
+  case Attribute::NoCFGSelectFormation:   return 1ULL << 57;
   case Attribute::Dereferenceable:
     llvm_unreachable("dereferenceable attribute not supported in raw format");
     break;
@@ -1316,6 +1317,8 @@
     return Attribute::NoBuiltin;
   case bitc::ATTR_KIND_NO_CAPTURE:
     return Attribute::NoCapture;
+  case bitc::ATTR_KIND_NO_CFG_SELECT_FORMATION:
+    return Attribute::NoCFGSelectFormation;
   case bitc::ATTR_KIND_NO_DUPLICATE:
     return Attribute::NoDuplicate;
   case bitc::ATTR_KIND_NO_IMPLICIT_FLOAT:
Index: llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
===================================================================
--- llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -618,6 +618,8 @@
     return bitc::ATTR_KIND_NO_BUILTIN;
   case Attribute::NoCapture:
     return bitc::ATTR_KIND_NO_CAPTURE;
+  case Attribute::NoCFGSelectFormation:
+    return bitc::ATTR_KIND_NO_CFG_SELECT_FORMATION;
   case Attribute::NoDuplicate:
     return bitc::ATTR_KIND_NO_DUPLICATE;
   case Attribute::NoImplicitFloat:
Index: llvm/lib/IR/Attributes.cpp
===================================================================
--- llvm/lib/IR/Attributes.cpp
+++ llvm/lib/IR/Attributes.cpp
@@ -285,6 +285,8 @@
     return "nobuiltin";
   if (hasAttribute(Attribute::NoCapture))
     return "nocapture";
+  if (hasAttribute(Attribute::NoCFGSelectFormation))
+    return "no_cfg_select_formation";
   if (hasAttribute(Attribute::NoDuplicate))
     return "noduplicate";
   if (hasAttribute(Attribute::NoImplicitFloat))
Index: llvm/lib/IR/Verifier.cpp
===================================================================
--- llvm/lib/IR/Verifier.cpp
+++ llvm/lib/IR/Verifier.cpp
@@ -1405,6 +1405,7 @@
   case Attribute::StackProtectStrong:
   case Attribute::SafeStack:
   case Attribute::NoRedZone:
+  case Attribute::NoCFGSelectFormation:
   case Attribute::NoImplicitFloat:
   case Attribute::Naked:
   case Attribute::InlineHint:
Index: llvm/lib/Transforms/IPO/ForceFunctionAttrs.cpp
===================================================================
--- llvm/lib/Transforms/IPO/ForceFunctionAttrs.cpp
+++ llvm/lib/Transforms/IPO/ForceFunctionAttrs.cpp
@@ -36,6 +36,7 @@
       .Case("minsize", Attribute::MinSize)
       .Case("naked", Attribute::Naked)
       .Case("nobuiltin", Attribute::NoBuiltin)
+      .Case("no_cfg_select_formation", Attribute::NoCFGSelectFormation)
       .Case("noduplicate", Attribute::NoDuplicate)
       .Case("noimplicitfloat", Attribute::NoImplicitFloat)
       .Case("noinline", Attribute::NoInline)
Index: llvm/lib/Transforms/Utils/CodeExtractor.cpp
===================================================================
--- llvm/lib/Transforms/Utils/CodeExtractor.cpp
+++ llvm/lib/Transforms/Utils/CodeExtractor.cpp
@@ -678,6 +678,7 @@
       case Attribute::NoRecurse:
       case Attribute::InlineHint:
       case Attribute::MinSize:
+      case Attribute::NoCFGSelectFormation:
       case Attribute::NoDuplicate:
       case Attribute::NoImplicitFloat:
       case Attribute::NoInline:
Index: llvm/lib/Transforms/Utils/SimplifyCFG.cpp
===================================================================
--- llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -2260,6 +2260,10 @@
   // dependence information for this check, but simplifycfg can't keep it up
   // to date, and this catches most of the cases we care about anyway.
   BasicBlock *BB = PN->getParent();
+  const Function *Fn = BB->getParent();
+  if (Fn && Fn->hasFnAttribute(Attribute::NoCFGSelectFormation))
+    return false;
+
   BasicBlock *IfTrue, *IfFalse;
   Value *IfCond = GetIfCondition(BB, IfTrue, IfFalse);
   if (!IfCond ||
@@ -5786,6 +5790,9 @@
 
 bool SimplifyCFGOpt::SimplifyCondBranch(BranchInst *BI, IRBuilder<> &Builder) {
   BasicBlock *BB = BI->getParent();
+  const Function *Fn = BB->getParent();
+  if (Fn && Fn->hasFnAttribute(Attribute::NoCFGSelectFormation))
+    return false;
 
   // Conditional branch
   if (isValueEqualityComparison(BI)) {
Index: llvm/test/Transforms/SimplifyCFG/no-select-formation.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/SimplifyCFG/no-select-formation.ll
@@ -0,0 +1,49 @@
+; RUN: opt < %s -simplifycfg -S | FileCheck %s
+
+define i32 @foo(i32 %x) no_cfg_select_formation {
+entry:
+  %x.addr = alloca i32, align 4
+  store i32 %x, i32* %x.addr, align 4
+  %0 = load i32, i32* %x.addr, align 4
+  %cmp = icmp sgt i32 %0, 16
+  br i1 %cmp, label %land.rhs, label %land.end
+
+land.rhs:
+  %1 = load i32, i32* %x.addr, align 4
+  %cmp1 = icmp slt i32 %1, 32
+  br label %land.end
+
+land.end:
+  %2 = phi i1 [ false, %entry ], [ %cmp1, %land.rhs ]
+  %conv = zext i1 %2 to i32
+  ret i32 %conv
+
+; CHECK-LABEL: define i32 @foo(i32 %x)
+; CHECK: br i1 %cmp, label %land.rhs, label %land.end
+; CHECK-LABEL: land.rhs:
+; CHECK: br label %land.end
+; CHECK-LABEL: land.end:
+; CHECK: phi {{.*}} %entry {{.*}} %land.rhs
+}
+
+define i32 @bar(i32 %x) {
+entry:
+  %x.addr = alloca i32, align 4
+  store i32 %x, i32* %x.addr, align 4
+  %0 = load i32, i32* %x.addr, align 4
+  %cmp = icmp sgt i32 %0, 16
+  br i1 %cmp, label %land.rhs, label %land.end
+
+land.rhs:
+  %1 = load i32, i32* %x.addr, align 4
+  %cmp1 = icmp slt i32 %1, 32
+  br label %land.end
+
+land.end:
+  %2 = phi i1 [ false, %entry ], [ %cmp1, %land.rhs ]
+  %conv = zext i1 %2 to i32
+  ret i32 %conv
+
+; CHECK-LABEL: define i32 @bar(i32 %x)
+; CHECK-NOT: br
+}