diff --git a/llvm/lib/Target/PowerPC/PPCBoolRetToInt.cpp b/llvm/lib/Target/PowerPC/PPCBoolRetToInt.cpp
--- a/llvm/lib/Target/PowerPC/PPCBoolRetToInt.cpp
+++ b/llvm/lib/Target/PowerPC/PPCBoolRetToInt.cpp
@@ -78,9 +78,9 @@
       Value *Curr = WorkList.back();
       WorkList.pop_back();
       auto *CurrUser = dyn_cast<User>(Curr);
-      // Operands of CallInst are skipped because they may not be Bool type,
-      // and their positions are defined by ABI.
-      if (CurrUser && !isa<CallInst>(Curr))
+      // Operands of CallInst/Constant are skipped because they may not be Bool
+      // type. For CallInst, their positions are defined by ABI.
+      if (CurrUser && !isa<CallInst>(Curr) && !isa<Constant>(Curr))
         for (auto &Op : CurrUser->operands())
           if (Defs.insert(Op).second)
             WorkList.push_back(Op);
@@ -90,6 +90,9 @@
 
   // Translate a i1 value to an equivalent i32/i64 value:
   Value *translate(Value *V) {
+    assert(V->getType() == Type::getInt1Ty(V->getContext()) &&
+           "Expect an i1 value");
+
     Type *IntTy = ST->isPPC64() ? Type::getInt64Ty(V->getContext())
                                 : Type::getInt32Ty(V->getContext());
 
@@ -252,9 +255,9 @@
       auto *First = dyn_cast<User>(Pair.first);
       auto *Second = dyn_cast<User>(Pair.second);
       assert((!First || Second) && "translated from user to non-user!?");
-      // Operands of CallInst are skipped because they may not be Bool type,
-      // and their positions are defined by ABI.
-      if (First && !isa<CallInst>(First))
+      // Operands of CallInst/Constant are skipped because they may not be Bool
+      // type. For CallInst, their positions are defined by ABI.
+      if (First && !isa<CallInst>(First) && !isa<Constant>(First))
         for (unsigned i = 0; i < First->getNumOperands(); ++i)
           Second->setOperand(i, BoolToIntMap[First->getOperand(i)]);
     }
diff --git a/llvm/test/CodeGen/PowerPC/pr46923.ll b/llvm/test/CodeGen/PowerPC/pr46923.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/PowerPC/pr46923.ll
@@ -0,0 +1,29 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -verify-machineinstrs -mtriple=powerpc64le-unknown-unknown \
+; RUN:   -ppc-asm-full-reg-names < %s | FileCheck %s
+
+@bar = external constant i64, align 8
+
+define i1 @foo() {
+; CHECK-LABEL: foo:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    li r3, 0
+; CHECK-NEXT:    isel r3, 0, r3, 4*cr5+lt
+; CHECK-NEXT:    blr
+entry:
+  br label %next
+
+next:
+  br i1 undef, label %true, label %false
+
+true:
+  br label %end
+
+false:
+  br label %end
+
+end:
+  %a = phi i1 [ icmp ugt (i64 0, i64 ptrtoint (i64* @bar to i64)), %true ],
+              [ icmp ugt (i64 0, i64 2), %false ]
+  ret i1 %a
+}