[LoopUnswitch] Add block frequency analysis to recognize hot/cold regions

[oota-llvm.git] / test / Transforms / LoopUnswitch / cold-loop.ll

diff --git a/test/Transforms/LoopUnswitch/cold-loop.ll b/test/Transforms/LoopUnswitch/cold-loop.ll
new file mode 100644 (file)
index 0000000..1fbc080
--- /dev/null
+++ b/test/Transforms/LoopUnswitch/cold-loop.ll
@@ -0,0 +1,52 @@
+; RUN: opt < %s -loop-unswitch -loop-unswitch-with-block-frequency -S 2>&1 | FileCheck %s
+
+;; trivial condition should be unswithed regardless of coldness.
+define i32 @test1(i1 %cond1, i1 %cond2) !prof !1 {
+  br i1 %cond1, label %loop_begin, label %loop_exit, !prof !0
+
+loop_begin:
+; CHECK: br i1 true, label %continue, label %loop_exit.loopexit
+  br i1 %cond2, label %continue, label %loop_exit  ; trivial condition
+
+continue:
+  call void @some_func1() noreturn nounwind
+  br label %loop_begin
+
+loop_exit:
+  ret i32 0
+}
+
+;; cold non-trivial condition should not be unswitched.
+define i32 @test2(i32* %var, i1 %cond1, i1 %cond2) !prof !1 {
+  br i1 %cond1, label %loop_begin, label %loop_exit, !prof !0
+
+loop_begin:
+  store i32 1, i32* %var
+; CHECK: br i1 %cond2, label %continue1, label %continue2
+  br i1 %cond2, label %continue1, label %continue2  ; non-trivial condition
+
+continue1:
+  call void @some_func1() noreturn nounwind
+  br label %joint
+
+continue2:
+  call void @some_func2() noreturn nounwind
+  br label %joint
+
+joint:
+;; unswitching will duplicate these calls.
+  call void @some_func3() noreturn nounwind
+  call void @some_func4() noreturn nounwind
+  br label %loop_begin
+
+loop_exit:
+  ret i32 0
+}
+
+declare void @some_func1() noreturn
+declare void @some_func2() noreturn
+declare void @some_func3() noreturn
+declare void @some_func4() noreturn
+
+!0 = !{!"branch_weights", i32 1, i32 100000000}
+!1 = !{!"function_entry_count", i64 100}