diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
index e5525133e5dbb..245fecb775e8c 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -1348,7 +1348,7 @@ Instruction *InstCombinerImpl::foldSelectValueEquivalence(SelectInst &Sel,
     // If we will be able to evaluate f(Y) to a constant, we can allow undef,
     // otherwise Y cannot be undef as we might pick different values for undef
     // in the cmp and in f(Y).
-    if (TrueVal == OldOp)
+    if (TrueVal == OldOp && (isa<Constant>(OldOp) || !isa<Constant>(NewOp)))
       return nullptr;
 
     if (Value *V = simplifyWithOpReplaced(TrueVal, OldOp, NewOp, SQ,
@@ -1925,17 +1925,6 @@ Instruction *InstCombinerImpl::foldSelectInstWithICmp(SelectInst &SI,
   ICmpInst::Predicate Pred = ICI->getPredicate();
   Value *CmpLHS = ICI->getOperand(0);
   Value *CmpRHS = ICI->getOperand(1);
-  if (CmpRHS != CmpLHS && isa<Constant>(CmpRHS) && !isa<Constant>(CmpLHS)) {
-    if (CmpLHS == TrueVal && Pred == ICmpInst::ICMP_EQ) {
-      // Transform (X == C) ? X : Y -> (X == C) ? C : Y
-      replaceOperand(SI, 1, CmpRHS);
-      Changed = true;
-    } else if (CmpLHS == FalseVal && Pred == ICmpInst::ICMP_NE) {
-      // Transform (X != C) ? Y : X -> (X != C) ? Y : C
-      replaceOperand(SI, 2, CmpRHS);
-      Changed = true;
-    }
-  }
 
   if (Instruction *NewSel = foldSelectICmpEq(SI, ICI, *this))
     return NewSel;
diff --git a/llvm/test/Transforms/InstCombine/select-value-equivalence.ll b/llvm/test/Transforms/InstCombine/select-value-equivalence.ll
index d55766ddf4040..812b4d8f6be79 100644
--- a/llvm/test/Transforms/InstCombine/select-value-equivalence.ll
+++ b/llvm/test/Transforms/InstCombine/select-value-equivalence.ll
@@ -322,12 +322,11 @@ define <2 x i8> @select_vec_op_const_no_undef(<2 x i8> %x) {
   ret <2 x i8> %xr
 }
 
-; FIXME: This is a miscompile.
 define <2 x i8> @select_vec_op_const_undef(<2 x i8> %x) {
 ; CHECK-LABEL: define <2 x i8> @select_vec_op_const_undef(
 ; CHECK-SAME: <2 x i8> [[X:%.*]]) {
 ; CHECK-NEXT:    [[XZ:%.*]] = icmp eq <2 x i8> [[X]], <i8 1, i8 undef>
-; CHECK-NEXT:    [[XR:%.*]] = select <2 x i1> [[XZ]], <2 x i8> <i8 1, i8 undef>, <2 x i8> <i8 4, i8 3>
+; CHECK-NEXT:    [[XR:%.*]] = select <2 x i1> [[XZ]], <2 x i8> [[X]], <2 x i8> <i8 4, i8 3>
 ; CHECK-NEXT:    ret <2 x i8> [[XR]]
 ;
   %xz = icmp eq <2 x i8> %x, <i8 1, i8 undef>