Revert "Temporarily Revert "Add basic loop fusion pass.""

The reversion apparently deleted the test/Transforms directory.

Will be re-reverting again.

llvm-svn: 358552
diff --git a/llvm/test/Transforms/LoopUnswitch/LIV-loop-condtion.ll b/llvm/test/Transforms/LoopUnswitch/LIV-loop-condtion.ll
new file mode 100644
index 0000000..bf4b68c
--- /dev/null
+++ b/llvm/test/Transforms/LoopUnswitch/LIV-loop-condtion.ll
@@ -0,0 +1,29 @@
+; RUN: opt < %s -loop-unswitch -loop-unswitch-threshold=0 -S 2>&1 | FileCheck %s
+; RUN: opt < %s -loop-unswitch -loop-unswitch-threshold=0 -enable-mssa-loop-dependency=true -verify-memoryssa -S 2>&1 | FileCheck %s
+
+; This is to test trivial loop unswitch only happens when trivial condition
+; itself is an LIV loop condition (not partial LIV which could occur in and/or).
+
+define i32 @test(i1 %cond1, i32 %var1) {
+entry:
+  br label %loop_begin
+
+loop_begin:
+  %var3 = phi i32 [%var1, %entry], [%var2, %do_something]
+  %cond2 = icmp eq i32 %var3, 10
+  %cond.and = and i1 %cond1, %cond2
+  
+; %cond.and only has %cond1 as LIV so no unswitch should happen.
+; CHECK: br i1 %cond.and, label %do_something, label %loop_exit
+  br i1 %cond.and, label %do_something, label %loop_exit 
+
+do_something:
+  %var2 = add i32 %var3, 1
+  call void @some_func() noreturn nounwind
+  br label %loop_begin
+
+loop_exit:
+  ret i32 0
+}
+
+declare void @some_func() noreturn