diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
--- a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -2606,7 +2606,10 @@
   // select i1 %c, <2 x i8> <1, 1>, <2 x i8> <0, 0>
   // because that may need 3 instructions to splat the condition value:
   // extend, insertelement, shufflevector.
-  if (SelType->isIntOrIntVectorTy() &&
+  //
+  // Do not handle i1 TrueVal and FalseVal otherwise would result in
+  // zext/sext i1 to i1.
+  if (SelType->isIntOrIntVectorTy() && !SelType->isIntOrIntVectorTy(1) &&
       CondVal->getType()->isVectorTy() == SelType->isVectorTy()) {
     // select C, 1, 0 -> zext C to int
     if (match(TrueVal, m_One()) && match(FalseVal, m_Zero()))