ScalarEvolution: Analyze trip count of loops with a switch guarding the exit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@201159 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 30 insertions, 0 deletions

diff --git a/test/Analysis/ScalarEvolution/trip-count-switch.ll b/test/Analysis/ScalarEvolution/trip-count-switch.ll
new file mode 100644
index 0000000000..2d2b6b4994
--- /dev/null
+++ b/test/Analysis/ScalarEvolution/trip-count-switch.ll
@@ -0,0 +1,30 @@
+; RUN: opt < %s -analyze -scalar-evolution | FileCheck %s
+
+declare void @foo()
+
+define void @test1() nounwind {
+entry:
+  br label %for.cond
+
+for.cond:                                         ; preds = %if.end, %entry
+  %i.0 = phi i32 [ 2, %entry ], [ %dec, %if.end ]
+  switch i32 %i.0, label %if.end [
+    i32 0, label %for.end
+    i32 1, label %if.then
+  ]
+
+if.then:                                          ; preds = %for.cond
+  tail call void @foo()
+  br label %if.end
+
+if.end:                                           ; preds = %for.cond, %if.then
+  %dec = add nsw i32 %i.0, -1
+  br label %for.cond
+
+for.end:                                          ; preds = %for.cond
+  ret void
+
+; CHECK-LABEL: @test1
+; CHECK: Loop %for.cond: backedge-taken count is 2
+; CHECK: Loop %for.cond: max backedge-taken count is 2
+}