Index: llvm/trunk/lib/Transforms/Utils/FunctionImportUtils.cpp
===================================================================
--- llvm/trunk/lib/Transforms/Utils/FunctionImportUtils.cpp
+++ llvm/trunk/lib/Transforms/Utils/FunctionImportUtils.cpp
@@ -67,12 +67,15 @@
     return true;
   }
 
-  // When exporting, consult the index.
-  auto Summaries = ImportIndex.findGlobalValueSummaryList(SGV->getGUID());
-  assert(Summaries != ImportIndex.end() &&
-         "Missing summary for global value when exporting");
-  assert(Summaries->second.size() == 1 && "Local has more than one summary");
-  auto Linkage = Summaries->second.front()->linkage();
+  // When exporting, consult the index. We can have more than one local
+  // with the same GUID, in the case of same-named locals in different but
+  // same-named source files that were compiled in their respective directories
+  // (so the source file name and resulting GUID is the same). Find the one
+  // in this module.
+  auto Summary = ImportIndex.findSummaryInModule(
+      SGV->getGUID(), SGV->getParent()->getModuleIdentifier());
+  assert(Summary && "Missing summary for global value when exporting");
+  auto Linkage = Summary->linkage();
   if (!GlobalValue::isLocalLinkage(Linkage)) {
     assert(!isNonRenamableLocal(*SGV) &&
            "Attempting to promote non-renamable local");
Index: llvm/trunk/test/ThinLTO/X86/Inputs/local_name_conflict1.ll
===================================================================
--- llvm/trunk/test/ThinLTO/X86/Inputs/local_name_conflict1.ll
+++ llvm/trunk/test/ThinLTO/X86/Inputs/local_name_conflict1.ll
@@ -0,0 +1,17 @@
+; ModuleID = 'local_name_conflict.o'
+source_filename = "local_name_conflict.c"
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Function Attrs: noinline nounwind uwtable
+define i32 @a() {
+entry:
+  %call = call i32 @foo()
+  ret i32 %call
+}
+
+; Function Attrs: noinline nounwind uwtable
+define internal i32 @foo() {
+entry:
+  ret i32 1
+}
Index: llvm/trunk/test/ThinLTO/X86/Inputs/local_name_conflict2.ll
===================================================================
--- llvm/trunk/test/ThinLTO/X86/Inputs/local_name_conflict2.ll
+++ llvm/trunk/test/ThinLTO/X86/Inputs/local_name_conflict2.ll
@@ -0,0 +1,17 @@
+; ModuleID = 'local_name_conflict.o'
+source_filename = "local_name_conflict.c"
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Function Attrs: noinline nounwind uwtable
+define i32 @b() {
+entry:
+  %call = call i32 @foo()
+  ret i32 %call
+}
+
+; Function Attrs: noinline nounwind uwtable
+define internal i32 @foo() {
+entry:
+  ret i32 2
+}
Index: llvm/trunk/test/ThinLTO/X86/local_name_conflict.ll
===================================================================
--- llvm/trunk/test/ThinLTO/X86/local_name_conflict.ll
+++ llvm/trunk/test/ThinLTO/X86/local_name_conflict.ll
@@ -0,0 +1,29 @@
+; Do setup work for all below tests: generate bitcode and combined index
+; RUN: opt -module-summary -module-hash %s -o %t.bc
+; RUN: opt -module-summary -module-hash %p/Inputs/local_name_conflict1.ll -o %t2.bc
+; RUN: opt -module-summary -module-hash %p/Inputs/local_name_conflict2.ll -o %t3.bc
+; RUN: llvm-lto -thinlto-action=thinlink -o %t4.bc %t.bc %t2.bc %t3.bc
+
+; Make sure foo is promoted and renamed without complaint in both
+; Inputs/local_name_conflict1.ll and Inputs/local_name_conflict2.ll
+; FIXME: Once the importer is fixed to import the correct copy of the
+; local, we should be able to verify that via an import action.
+; RUN: llvm-lto -thinlto-action=promote %t2.bc -thinlto-index=%t4.bc -o - | llvm-dis -o - | FileCheck %s --check-prefix=EXPORTSTATIC
+; RUN: llvm-lto -thinlto-action=promote %t3.bc -thinlto-index=%t4.bc -o - | llvm-dis -o - | FileCheck %s --check-prefix=EXPORTSTATIC
+; EXPORTSTATIC: define hidden i32 @foo.llvm.
+
+; ModuleID = 'local_name_conflict_main.o'
+source_filename = "local_name_conflict_main.c"
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Function Attrs: noinline nounwind uwtable
+define i32 @main() {
+entry:
+  %retval = alloca i32, align 4
+  store i32 0, i32* %retval, align 4
+  %call = call i32 (...) @b()
+  ret i32 %call
+}
+
+declare i32 @b(...)