[IRMover] Add comment and fix test case
llvm-svn: 323407
diff --git a/llvm/lib/Linker/IRMover.cpp b/llvm/lib/Linker/IRMover.cpp
index f7170e7..6863a89 100644
--- a/llvm/lib/Linker/IRMover.cpp
+++ b/llvm/lib/Linker/IRMover.cpp
@@ -95,6 +95,12 @@
for (StructType *Ty : SpeculativeDstOpaqueTypes)
DstResolvedOpaqueTypes.erase(Ty);
} else {
+ // SrcTy and DstTy are recursively ismorphic. We clear names of SrcTy
+ // and all its descendants to lower amount of renaming in LLVM context
+ // Renaming occurs because we load all source modules to the same context
+ // and declaration with existing name gets renamed (i.e Foo -> Foo.42).
+ // As a result we may get several different types in the destination
+ // module, which are in fact the same.
for (Type *Ty : SpeculativeTypes)
if (auto *STy = dyn_cast<StructType>(Ty))
if (STy->hasName())
diff --git a/llvm/test/Linker/type-unique-dst-types.ll b/llvm/test/Linker/type-unique-dst-types.ll
index 1adad49..cfcad13 100644
--- a/llvm/test/Linker/type-unique-dst-types.ll
+++ b/llvm/test/Linker/type-unique-dst-types.ll
@@ -1,6 +1,8 @@
; RUN: llvm-link %p/type-unique-dst-types.ll \
; RUN: %p/Inputs/type-unique-dst-types2.ll \
-; RUN: %p/Inputs/type-unique-dst-types3.ll -S -o - | FileCheck %s
+; RUN: %p/Inputs/type-unique-dst-types3.ll -S -o %t1.ll
+; RUN: cat %t1.ll | FileCheck %s
+; RUN: cat %t1.ll | FileCheck --check-prefix=RENAMED %s
; This tests the importance of keeping track of which types are part of the
; destination module.
@@ -14,6 +16,8 @@
; CHECK: @g1 = external global %A
; CHECK: @g2 = external global %A
+; RENAMED-NOT: A.11
+
%A = type { %B }
%B = type { i8 }
@g3 = external global %A