Index: lldb/test/Shell/Unwind/Inputs/split-machine-functions.ll
===================================================================
--- /dev/null
+++ lldb/test/Shell/Unwind/Inputs/split-machine-functions.ll
@@ -0,0 +1,105 @@
+;; IR + Profile to split machine functions with -fsplit-machine-functions
+;; Source used to generate this file
+;; int k;
+
+;; int baz() {
+;;   return 0;
+;; }
+;;
+;; int bar() {
+;;   return 0;
+;; }
+;;
+;; int foo() {
+;;   if (k)
+;;     baz();
+;;   else
+;;     bar();
+;;   return 0;
+;; }
+;;
+;; int main() {
+;;   foo();
+;;   return 0;
+;; }
+
+;; Commands:
+;; clang -fprofile-generate -O0 source.cc
+;; ./a.out && llvm-profdata merge -o default.profdata *.profraw
+;; clang -fprofile-use -O0 source.cc -emit-llvm -S
+
+target triple = "x86_64-unknown-linux-gnu"
+
+@k = dso_local global i32 0, align 4
+
+; Function Attrs: cold noinline nounwind optnone uwtable
+define dso_local i32 @_Z3bazv() !prof !31 {
+  ret i32 0
+}
+
+; Function Attrs: inlinehint noinline nounwind optnone uwtable
+define dso_local i32 @_Z3barv() !prof !32 {
+  ret i32 0
+}
+
+; Function Attrs: inlinehint noinline nounwind optnone uwtable
+define dso_local i32 @_Z3foov() !prof !32 {
+  %1 = load i32, i32* @k, align 4
+  %2 = icmp ne i32 %1, 0
+  br i1 %2, label %3, label %5, !prof !33
+
+3:                                                ; preds = %0
+  %4 = call i32 @_Z3bazv()
+  br label %7
+
+5:                                                ; preds = %0
+  %6 = call i32 @_Z3barv()
+  br label %7
+
+7:                                                ; preds = %5, %3
+  ret i32 0
+}
+
+; Function Attrs: inlinehint noinline norecurse nounwind optnone uwtable
+define dso_local i32 @main() !prof !32 {
+  %1 = alloca i32, align 4
+  store i32 0, i32* %1, align 4
+  %2 = call i32 @_Z3foov()
+  ret i32 0
+}
+
+!llvm.module.flags = !{!0, !1}
+
+!0 = !{i32 1, !"wchar_size", i32 4}
+!1 = !{i32 1, !"ProfileSummary", !2}
+!2 = !{!3, !4, !5, !6, !7, !8, !9, !10, !11, !12}
+!3 = !{!"ProfileFormat", !"InstrProf"}
+!4 = !{!"TotalCount", i64 3}
+!5 = !{!"MaxCount", i64 1}
+!6 = !{!"MaxInternalCount", i64 1}
+!7 = !{!"MaxFunctionCount", i64 1}
+!8 = !{!"NumCounts", i64 5}
+!9 = !{!"NumFunctions", i64 4}
+!10 = !{!"IsPartialProfile", i64 0}
+!11 = !{!"PartialProfileRatio", double 0.000000e+00}
+!12 = !{!"DetailedSummary", !13}
+!13 = !{!14, !15, !16, !17, !18, !19, !20, !21, !22, !23, !24, !25, !26, !27, !28, !29}
+!14 = !{i32 10000, i64 0, i32 0}
+!15 = !{i32 100000, i64 0, i32 0}
+!16 = !{i32 200000, i64 0, i32 0}
+!17 = !{i32 300000, i64 0, i32 0}
+!18 = !{i32 400000, i64 1, i32 3}
+!19 = !{i32 500000, i64 1, i32 3}
+!20 = !{i32 600000, i64 1, i32 3}
+!21 = !{i32 700000, i64 1, i32 3}
+!22 = !{i32 800000, i64 1, i32 3}
+!23 = !{i32 900000, i64 1, i32 3}
+!24 = !{i32 950000, i64 1, i32 3}
+!25 = !{i32 990000, i64 1, i32 3}
+!26 = !{i32 999000, i64 1, i32 3}
+!27 = !{i32 999900, i64 1, i32 3}
+!28 = !{i32 999990, i64 1, i32 3}
+!29 = !{i32 999999, i64 1, i32 3}
+!31 = !{!"function_entry_count", i64 0}
+!32 = !{!"function_entry_count", i64 1}
+!33 = !{!"branch_weights", i32 1, i32 0}
Index: lldb/test/Shell/Unwind/split-machine-functions.test
===================================================================
--- /dev/null
+++ lldb/test/Shell/Unwind/split-machine-functions.test
@@ -0,0 +1,39 @@
+# Test to check if machine function splitter still poduces the right backtraces
+# with lldb when a function is split into a hot and cold part and the cold part
+# is executed.  The cold part has the same function symbol name but with a
+# ".cold" suffix and this test checks that the back trace is clear.
+
+# UNSUPPORTED: system-darwin, system-windows
+# REQUIRES: target-x86_64
+# REQUIRES: lld
+
+# RUN: %clang_host %p/Inputs/split-machine-functions.ll -o %t
+# RUN: %lldb %t -s %s -o exit | FileCheck  %s --check-prefix=DEFAULT
+#
+# RUN: %clang_host %p/Inputs/split-machine-functions.ll -fsplit-machine-functions -o %t
+# RUN: %lldb %t -s %s -o exit | FileCheck  %s --check-prefix=SPLIT
+#
+# Test a permutation where foo.cold is very far from foo.
+# RUN: echo "_Z3foov" > %t.order
+# RUN: echo "main" >> %t.order
+# RUN: echo "_Z3barv" >> %t.order
+# RUN: echo "_Z3bazv" >> %t.order
+# RUN: echo "_Z3foov.cold" >> %t.order
+# RUN: %clang_host %p/Inputs/split-machine-functions.ll -fsplit-machine-functions -o %t -fuse-ld=lld -Wl,--symbol-ordering-file,%t.order -Wl,--warn-symbol-ordering -Wl,--fatal-warnings
+# RUN: %lldb %t -s %s -o exit | FileCheck  %s --check-prefix=SPLIT
+
+breakpoint set -n bar
+# DEFAULT: Breakpoint 1: where = {{.*}}`bar
+# SPLIT: Breakpoint 1: where = {{.*}}`bar
+
+process launch
+# DEFAULT: stop reason = breakpoint 1.1
+# SPLIT: stop reason = breakpoint 1.1
+
+thread backtrace
+# DEFAULT: frame #0: {{.*}}`bar
+# DEFAULT: frame #1: {{.*}}`foo() +
+# DEFAULT: frame #2: {{.*}}`main +
+# SPLIT: frame #0: {{.*}}`bar
+# SPLIT: frame #1: {{.*}}`foo() (.cold) +
+# SPLIT: frame #2: {{.*}}`main +