Add a test for the recent regression.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133009 91177308-0d34-0410-b5e6-96231b3b80d8

test/CodeGen/X86/undef-label.ll

@@ -0,0 +1,19 @@
+; RUN: llc < %s -mtriple=x86_64-linux | FileCheck %s
+
+; This is a case where we would incorrectly conclude that LBB0_1 could only
+; be reached via fall through and would therefore omit the label.
+
+; CHECK:      jne     .LBB0_1
+; CHECK-NEXT: jnp     .LBB0_3
+; CHECK-NEXT: .LBB0_1:
+
+define void @xyz() {
+entry:
+  br i1 fcmp oeq (double fsub (double undef, double undef), double 0.000000e+00), label %bar, label %foo
+
+foo:
+  br i1 fcmp ogt (double fdiv (double fsub (double fmul (double undef, double undef), double fsub (double undef, double undef)), double fmul (double undef, double undef)), double 1.0), label %foo, label %bar
+
+bar:
+  ret void
+}