diff --git a/llvm/include/llvm/LTO/Config.h b/llvm/include/llvm/LTO/Config.h
--- a/llvm/include/llvm/LTO/Config.h
+++ b/llvm/include/llvm/LTO/Config.h
@@ -288,6 +288,12 @@
     enableDebugTypeODRUniquing();
     setDiagnosticHandler(
         std::make_unique<LTOLLVMDiagnosticHandler>(&DiagHandler), true);
+    // Don't leave the decision to use opaque pointers to the BitcodeReader
+    // as we may be mixing bitcode using opaque and typed pointers and we can
+    // only upgrade typed pointers to opaque pointers.
+    if (!hasSetOpaquePointersValue()) {
+      setOpaquePointers(true);
+    }
   }
   DiagnosticHandlerFunction DiagHandler;
 };
diff --git a/llvm/test/LTO/X86/Inputs/opaque-pointers.ll b/llvm/test/LTO/X86/Inputs/opaque-pointers.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/LTO/X86/Inputs/opaque-pointers.ll
@@ -0,0 +1,7 @@
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i64 @foo(ptr %p) {
+  %t = load i64, ptr %p
+  ret i64 %t
+}
diff --git a/llvm/test/LTO/X86/mix-opaque-typed.ll b/llvm/test/LTO/X86/mix-opaque-typed.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/LTO/X86/mix-opaque-typed.ll
@@ -0,0 +1,19 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: llvm-as -opaque-pointers=0 %s -o %t-typed.bc
+; RUN: llvm-as -opaque-pointers=1 %S/Inputs/opaque-pointers.ll -o %t-opaque.bc
+; RUN: llvm-lto2 run -o %t-lto.bc %t-typed.bc %t-opaque.bc -save-temps \
+; RUN:     -r %t-typed.bc,call_foo,px -r %t-typed.bc,foo,l \
+; RUN:     -r %t-opaque.bc,foo,px
+; RUN: opt -S -o - %t-lto.bc.0.4.opt.bc | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+declare i64 @foo(i64* %p);
+
+define i64 @call_foo(i64* %p) {
+  ; CHECK-LABEL: define i64 @call_foo(ptr nocapture readonly %p) local_unnamed_addr #0 {
+  ; CHECK-NEXT: %t.i = load i64, ptr %p, align 8
+  %t = call i64 @foo(i64* %p)
+  ret i64 %t
+}