1 files changed, 41 insertions, 0 deletions
diff --git a/llvm/test/ThinLTO/X86/writeonly.ll b/llvm/test/ThinLTO/X86/writeonly.ll
new file mode 100644
index 00000000000..7c2af6d9cce
--- /dev/null
+++ b/llvm/test/ThinLTO/X86/writeonly.ll
@@ -0,0 +1,41 @@
+; Checks that we optimize writeonly variables and corresponding stores using llvm-lto
+; -stats requires asserts
+; REQUIRES: asserts
+
+; RUN: opt -module-summary %s -o %t1.bc
+; RUN: opt -module-summary %p/Inputs/index-const-prop.ll -o %t2.bc
+; RUN: llvm-lto -thinlto-action=thinlink -o %t3.index.bc %t1.bc %t2.bc
+
+; Check that we optimize write-only variables
+; RUN: llvm-lto -thinlto-action=import -exported-symbol=main  %t1.bc -thinlto-index=%t3.index.bc -o %t1.imported.bc -stats 2>&1 | FileCheck %s --check-prefix=STATS
+; RUN: llvm-dis %t1.imported.bc -o - | FileCheck %s --check-prefix=IMPORT
+; RUN: llvm-lto -thinlto-action=optimize %t1.imported.bc -o - | llvm-dis - -o - | FileCheck %s --check-prefix=OPTIMIZE
+
+; IMPORT: @gFoo.llvm.0 = internal unnamed_addr global i32 1, align 4, !dbg !0
+; IMPORT-NEXT: @gBar = internal local_unnamed_addr global i32 2, align 4, !dbg !5
+; IMPORT: !DICompileUnit({{.*}})
+
+; STATS:  2 module-summary-index - Number of live global variables marked write only 
+
+; Check that we've optimized out variables and corresponding stores
+; OPTIMIZE-NOT:  gFoo
+; OPTIMIZE-NOT:  gBar
+; OPTIMIZE:      i32 @main
+; OPTIMIZE-NEXT:   %1 = tail call i32 @rand()
+; OPTIMIZE-NEXT:   %2 = tail call i32 @rand()
+; OPTIMIZE-NEXT:   ret i32 0
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-linux-gnu"
+
+@gBar = external global i32
+
+; Should not be counted in the stats of live write only variables since it is
+; dead and will be dropped anyway.
+@gDead = internal unnamed_addr global i32 1, align 4
+
+define i32 @main() local_unnamed_addr {
+  tail call void @baz()
+  ret i32 0
+}
+declare void @baz() local_unnamed_addr