Index: llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp
===================================================================
--- llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp
+++ llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp
@@ -741,24 +741,28 @@
         return;
 
     // We only keep live symbols that are known to be non-prevailing if any are
-    // available_externally. Those symbols are discarded later in the
-    // EliminateAvailableExternally pass and setting them to not-live breaks
-    // downstreams users of liveness information (PR36483).
+    // available_externally, linkonceodr, weakodr. Those symbols are discarded
+    // later in the EliminateAvailableExternally pass and setting them to
+    // not-live could break downstreams users of liveness information (PR36483)
+    // or limit optimization opportunities.
     if (isPrevailing(VI.getGUID()) == PrevailingType::No) {
-      bool AvailableExternally = false;
+      bool KeepAliveLinkage = false;
       bool Interposable = false;
       for (auto &S : VI.getSummaryList()) {
-        if (S->linkage() == GlobalValue::AvailableExternallyLinkage)
-          AvailableExternally = true;
+        if (S->linkage() == GlobalValue::AvailableExternallyLinkage ||
+            S->linkage() == GlobalValue::WeakODRLinkage ||
+            S->linkage() == GlobalValue::LinkOnceODRLinkage)
+          KeepAliveLinkage = true;
         else if (GlobalValue::isInterposableLinkage(S->linkage()))
           Interposable = true;
       }
 
-      if (!AvailableExternally)
+      if (!KeepAliveLinkage)
         return;
 
       if (Interposable)
-        report_fatal_error("Interposable and available_externally symbol");
+        report_fatal_error(
+          "Interposable and available_externally/linkonce_odr/weak_odr symbol");
     }
 
     for (auto &S : VI.getSummaryList())
Index: llvm/trunk/test/LTO/Resolution/X86/cache-prevailing.ll
===================================================================
--- llvm/trunk/test/LTO/Resolution/X86/cache-prevailing.ll
+++ llvm/trunk/test/LTO/Resolution/X86/cache-prevailing.ll
@@ -10,7 +10,7 @@
 target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-pc-windows-msvc19.11.0"
 
-@foo = linkonce_odr constant i32 1, comdat
+@foo = linkonce constant i32 1, comdat
 $foo = comdat any
 
 define i32* @bar() {
Index: llvm/trunk/test/ThinLTO/X86/deadstrip.ll
===================================================================
--- llvm/trunk/test/ThinLTO/X86/deadstrip.ll
+++ llvm/trunk/test/ThinLTO/X86/deadstrip.ll
@@ -18,6 +18,8 @@
 ; RUN:   -r %t1.bc,_baz,l \
 ; RUN:   -r %t1.bc,_boo,l \
 ; RUN:   -r %t1.bc,_live_available_externally_func,l \
+; RUN:   -r %t1.bc,_live_linkonce_odr_func,l \
+; RUN:   -r %t1.bc,_live_weak_odr_func,l \
 ; RUN:   -r %t2.bc,_baz,pl \
 ; RUN:   -r %t2.bc,_boo,pl \
 ; RUN:   -r %t2.bc,_dead_func,l \
@@ -33,12 +35,16 @@
 ; COMBINED-DAG: <COMBINED {{.*}} op2=119
 ; Live, dso_local, Internal
 ; COMBINED-DAG: <COMBINED {{.*}} op2=103
+; Live, Local, LinkOnceODR
+; COMBINED-DAG: <COMBINED {{.*}} op2=99
 ; Live, Local, AvailableExternally
 ; COMBINED-DAG: <COMBINED {{.*}} op2=97
 ; Live, Local, External
 ; COMBINED-DAG: <COMBINED {{.*}} op2=96
 ; COMBINED-DAG: <COMBINED {{.*}} op2=96
 ; COMBINED-DAG: <COMBINED {{.*}} op2=96
+; Live, Local, WeakODR
+; COMBINED-DAG: <COMBINED {{.*}} op2=69
 ; Local, (Dead)
 ; COMBINED-DAG: <COMBINED {{.*}} op2=64
 ; COMBINED-DAG: <COMBINED {{.*}} op2=64
@@ -95,6 +101,8 @@
 ; RUN:   -r %t1.bc,_baz,l \
 ; RUN:   -r %t1.bc,_boo,l \
 ; RUN:   -r %t1.bc,_live_available_externally_func,l \
+; RUN:   -r %t1.bc,_live_linkonce_odr_func,l \
+; RUN:   -r %t1.bc,_live_weak_odr_func,l \
 ; RUN:   -r %t3.bc,_baz,pl \
 ; RUN:   -r %t3.bc,_boo,pl \
 ; RUN:   -r %t3.bc,_dead_func,l \
@@ -140,6 +148,15 @@
     ret void
 }
 
+
+define linkonce_odr void @live_linkonce_odr_func() {
+    ret void
+}
+
+define weak_odr void @live_weak_odr_func() {
+    ret void
+}
+
 define available_externally void @live_available_externally_func() {
     ret void
 }
@@ -147,6 +164,8 @@
 define void @main() {
     call void @bar()
     call void @bar_internal()
+    call void @live_linkonce_odr_func()
+    call void @live_weak_odr_func()
     call void @live_available_externally_func()
     ret void
 }
Index: llvm/trunk/test/Transforms/FunctionImport/not-prevailing.ll
===================================================================
--- llvm/trunk/test/Transforms/FunctionImport/not-prevailing.ll
+++ llvm/trunk/test/Transforms/FunctionImport/not-prevailing.ll
@@ -3,7 +3,7 @@
 ; RUN: not llvm-lto2 run -o %t3.bc %t1.bc %t2.bc -r %t1.bc,bar,px \
 ; RUN:     -r %t1.bc,foo,x -r %t2.bc,foo,x -save-temps 2>&1 | FileCheck %s
 
-; CHECK: Interposable and available_externally symbol
+; CHECK: Interposable and available_externally/linkonce_odr/weak_odr symbol
 
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"