5 files changed, 180 insertions, 2 deletions
diff --git a/llvm/test/ThinLTO/X86/Inputs/dot-dumper2.ll b/llvm/test/ThinLTO/X86/Inputs/dot-dumper2.ll
new file mode 100644
index 00000000000..6d9783e92d0
--- /dev/null
+++ b/llvm/test/ThinLTO/X86/Inputs/dot-dumper2.ll
@@ -0,0 +1,4 @@
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+@A = local_unnamed_addr global i32 10, align 4
diff --git a/llvm/test/ThinLTO/X86/dot-dumper2.ll b/llvm/test/ThinLTO/X86/dot-dumper2.ll
new file mode 100644
index 00000000000..8cc9822aed4
--- /dev/null
+++ b/llvm/test/ThinLTO/X86/dot-dumper2.ll
@@ -0,0 +1,43 @@
+; Test writeOnly attribute
+; RUN: opt -module-summary %s -o %t1.bc
+; RUN: opt -module-summary %p/Inputs/dot-dumper2.ll -o %t2.bc
+; RUN: llvm-lto2 run -save-temps %t1.bc %t2.bc -o %t3 \
+; RUN:  -r=%t1.bc,main,px \
+; RUN:  -r=%t1.bc,A, \
+; RUN:  -r=%t2.bc,A,p
+
+; RUN: cat %t3.index.dot | FileCheck --check-prefix=COMBINED %s
+
+; COMBINED: digraph Summary {
+; COMBINED-NEXT:  // Module:
+; COMBINED-NEXT:  subgraph cluster_0 {
+; COMBINED-NEXT:    style = filled;
+; COMBINED-NEXT:    color = lightgrey;
+; COMBINED-NEXT:    label =
+; COMBINED-NEXT:    node [style=filled,fillcolor=lightblue];
+; COMBINED-NEXT:    M0_[[MAIN:[0-9]+]] [shape="record",label="main|extern (inst: 2, ffl: 00000)}"]; // function
+; COMBINED-NEXT:    // Edges:
+; COMBINED-NEXT:  }
+; COMBINED-NEXT:  // Module:
+; COMBINED-NEXT:  subgraph cluster_1 {
+; COMBINED-NEXT:    style = filled;
+; COMBINED-NEXT:    color = lightgrey;
+; COMBINED-NEXT:    label =
+; COMBINED-NEXT:    node [style=filled,fillcolor=lightblue];
+; COMBINED-NEXT:    M1_[[A:[0-9]+]] [shape="Mrecord",label="A|extern}"]; // variable, writeOnly
+; COMBINED-NEXT:    // Edges:
+; COMBINED-NEXT:  }
+; COMBINED-NEXT:  // Cross-module edges:
+; COMBINED-NEXT:  M0_[[MAIN]] -> M1_[[A]] [style=dashed,color=violetred]; // writeOnly-ref
+; COMBINED-NEXT: }
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+@A = external local_unnamed_addr global i32, align 4
+
+; Function Attrs: nounwind uwtable
+define i32 @main() local_unnamed_addr {
+  store i32 42, i32* @A, align 4
+  ret i32 0
+}
diff --git a/llvm/test/ThinLTO/X86/index-const-prop2.ll b/llvm/test/ThinLTO/X86/index-const-prop2.ll
index 96b7593dd4f..a5fbbdf1e92 100644
--- a/llvm/test/ThinLTO/X86/index-const-prop2.ll
+++ b/llvm/test/ThinLTO/X86/index-const-prop2.ll
@@ -11,8 +11,10 @@
 ; RUN:  -r=%t2.bc,rand, \
 ; RUN:  -r=%t2.bc,gBar,pl \
 ; RUN:  -r=%t1.bc,main,plx \
+; RUN:  -r=%t1.bc,main2,pl \
 ; RUN:  -r=%t1.bc,foo, \
 ; RUN:  -r=%t1.bc,bar, \
+; RUN:  -r=%t1.bc,baz, \
 ; RUN:  -r=%t1.bc,gBar, \
 ; RUN:  -o %t3
 ; RUN: llvm-dis %t3.1.3.import.bc -o - | FileCheck %s --check-prefix=IMPORT
@@ -26,11 +28,32 @@
 ; RUN:  -r=%t2.bc,rand, \
 ; RUN:  -r=%t2.bc,gBar,plx \
 ; RUN:  -r=%t1.bc,main,plx \
+; RUN:  -r=%t1.bc,main2,pl \
 ; RUN:  -r=%t1.bc,foo, \
 ; RUN:  -r=%t1.bc,bar, \
+; RUN:  -r=%t1.bc,baz, \
 ; RUN:  -r=%t1.bc,gBar, \
-; RUN:  -o %t3
-; RUN: llvm-dis %t3.1.3.import.bc -o - | FileCheck %s --check-prefix=IMPORT2
+; RUN:  -o %t4
+; RUN: llvm-dis %t4.1.3.import.bc -o - | FileCheck %s --check-prefix=IMPORT2
+
+; RUN: llvm-lto2 run %t1.bc %t2.bc -save-temps \
+; RUN:  -r=%t2.bc,foo,pl \
+; RUN:  -r=%t2.bc,bar,pl \
+; RUN:  -r=%t2.bc,baz,pl \
+; RUN:  -r=%t2.bc,rand, \
+; RUN:  -r=%t2.bc,gBar,pl \
+; RUN:  -r=%t1.bc,main,pl \
+; RUN:  -r=%t1.bc,main2,plx \
+; RUN:  -r=%t1.bc,foo, \
+; RUN:  -r=%t1.bc,bar, \
+; RUN:  -r=%t1.bc,baz, \
+; RUN:  -r=%t1.bc,gBar, \
+; RUN:  -o %t5
+; RUN: llvm-dis %t5.1.3.import.bc -o - | FileCheck %s --check-prefix=IMPORT
+; RUN: llvm-dis %t5.1.5.precodegen.bc -o - | FileCheck %s --check-prefix=CODEGEN2
+; Check that gFoo and gBar were eliminated from source module together
+; with corresponsing stores
+; RUN: llvm-dis %t5.2.5.precodegen.bc -o - | FileCheck %s --check-prefix=CODEGEN2-SRC
 
 ; IMPORT:       @gFoo.llvm.0 = internal unnamed_addr global i32 1, align 4
 ; IMPORT-NEXT:  @gBar = internal local_unnamed_addr global i32 2, align 4
@@ -41,6 +64,16 @@
 
 ; IMPORT2: @gBar = available_externally dso_local local_unnamed_addr global i32 2, align 4
 
+; CODEGEN2:      i32 @main2
+; CODEGEN2-NEXT:   %1 = tail call i32 @rand()
+; CODEGEN2-NEXT:   %2 = tail call i32 @rand()
+; CODEGEN2-NEXT:   ret i32 0
+
+; CODEGEN2-SRC:       void @baz()
+; CODEGEN2-SRC-NEXT:    %1 = tail call i32 @rand()
+; CODEGEN2-SRC-NEXT:    %2 = tail call i32 @rand()
+; CODEGEN2-SRC-NEXT:    ret void
+
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-pc-linux-gnu"
 
@@ -54,6 +87,13 @@ define i32 @main() local_unnamed_addr {
   ret i32 %add
 }
 
+define i32 @main2() local_unnamed_addr {
+  tail call void @baz()
+  ret i32 0
+}
+
 declare i32 @foo(...) local_unnamed_addr
 
 declare i32 @bar(...) local_unnamed_addr
+
+declare void @baz() local_unnamed_addr
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
diff --git a/llvm/test/ThinLTO/X86/writeonly2.ll b/llvm/test/ThinLTO/X86/writeonly2.ll
new file mode 100644
index 00000000000..b1e53ba47b5
--- /dev/null
+++ b/llvm/test/ThinLTO/X86/writeonly2.ll
@@ -0,0 +1,50 @@
+; Check that we optimize out writeonly variables and corresponding stores.
+; This test uses llvm-lto2
+
+; RUN: opt -module-summary %s -o %t1.bc
+; RUN: opt -module-summary %p/Inputs/index-const-prop.ll -o %t2.bc
+; RUN: llvm-lto2 run %t1.bc %t2.bc -save-temps \
+; RUN:  -r=%t2.bc,foo,pl \
+; RUN:  -r=%t2.bc,bar,pl \
+; RUN:  -r=%t2.bc,baz,pl \
+; RUN:  -r=%t2.bc,rand, \
+; RUN:  -r=%t2.bc,gBar,pl \
+; RUN:  -r=%t1.bc,main,plx \
+; RUN:  -r=%t1.bc,baz, \
+; RUN:  -r=%t1.bc,gBar, \
+; RUN:  -o %t3
+; RUN: llvm-dis %t3.1.3.import.bc -o - | FileCheck %s --check-prefix=IMPORT
+; RUN: llvm-dis %t3.1.5.precodegen.bc -o - | FileCheck %s --check-prefix=CODEGEN
+; Check that gFoo and gBar were eliminated from source module together
+; with corresponsing stores
+; RUN: llvm-dis %t3.2.5.precodegen.bc -o - | FileCheck %s --check-prefix=CODEGEN-SRC
+
+; IMPORT:       @gFoo.llvm.0 = internal unnamed_addr global i32 1, align 4
+; IMPORT-NEXT:  @gBar = internal local_unnamed_addr global i32 2, align 4
+; IMPORT:       !DICompileUnit({{.*}})
+
+; CODEGEN-NOT:  gFoo
+; CODEGEN-NOT:  gBar
+; CODEGEN:      i32 @main
+; CODEGEN-NEXT:   %1 = tail call i32 @rand()
+; CODEGEN-NEXT:   %2 = tail call i32 @rand()
+; CODEGEN-NEXT:   ret i32 0
+
+; CODEGEN-SRC-NOT:   gFoo
+; CODEGEN-SRC-NOT:   gBar
+; CODEGEN-SRC:       void @baz()
+; CODEGEN-SRC-NEXT:    %1 = tail call i32 @rand()
+; CODEGEN-SRC-NEXT:    %2 = tail call i32 @rand()
+; CODEGEN-SRC-NEXT:    ret void
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-linux-gnu"
+
+; We should be able to link external definition of gBar to its declaration
+@gBar = external global i32
+
+define i32 @main() local_unnamed_addr {
+  tail call void @baz()
+  ret i32 0
+}
+declare void @baz() local_unnamed_addr