Add 132986 back, but avoid non-determinism if a bb address gets reused.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132995 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 41 insertions, 0 deletions

diff --git a/test/CodeGen/X86/tail-threshold.ll b/test/CodeGen/X86/tail-threshold.ll
new file mode 100644
index 0000000000..9541c01a4f
--- /dev/null
+++ b/test/CodeGen/X86/tail-threshold.ll
@@ -0,0 +1,41 @@
+; RUN: llc -march=x86-64 %s -stats -tail-merge-threshold 2 -o /dev/null |& FileCheck %s
+
+; Test that we still do some merging if a block has more than
+; tail-merge-threshold predecessors.
+
+; CHECK: 2 branchfolding   - Number of block tails merged
+
+declare void @bar()
+
+define void @foo(i32 %xxx) {
+entry:
+  switch i32 %xxx, label %bb4 [
+    i32 0, label %bb0
+    i32 1, label %bb1
+    i32 2, label %bb2
+    i32 3, label %bb3
+  ]
+
+bb0:
+  call void @bar()
+  br label %bb5
+
+bb1:
+ call void @bar()
+ br label %bb5
+
+bb2:
+  call void @bar()
+  br label %bb5
+
+bb3:
+  call void @bar()
+  br label %bb5
+
+bb4:
+  call void @bar()
+  br label %bb5
+
+bb5:
+  ret void
+}