Index: lib/Transforms/InstCombine/InstCombineCompares.cpp
===================================================================
--- lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -3777,6 +3777,11 @@
                                              const unsigned SIOpd) {
   assert((SIOpd == 1 || SIOpd == 2) && "Invalid select operand!");
   if (isChainSelectCmpBranch(SI) && Icmp->getPredicate() == ICmpInst::ICMP_EQ) {
+    // need to disable for the case branching to same block like
+    // br il %5, label %n, label %n.
+    if (SI->getParent()->getTerminator()->getSuccessor(1) ==
+        SI->getParent()->getTerminator()->getSuccessor(0))
+      return false;
     BasicBlock *Succ = SI->getParent()->getTerminator()->getSuccessor(1);
     // The check for the unique predecessor is not the best that can be
     // done. But it protects efficiently against cases like when SI's
Index: test/Transforms/InstCombine/select-cmp-br.ll
===================================================================
--- test/Transforms/InstCombine/select-cmp-br.ll
+++ test/Transforms/InstCombine/select-cmp-br.ll
@@ -153,3 +153,29 @@
 ; CHECK: or
 ; CHECK-NOT: select
 }
+
+define void @test6(%C*) {
+entry:
+  %1 = getelementptr inbounds %C, %C* %0, i64 0, i32 0, i32 0
+  %m = load i64*, i64** %1, align 8
+  %2 = getelementptr inbounds %C, %C* %0, i64 1, i32 0, i32 0
+  %n = load i64*, i64** %2, align 8
+  %3 = getelementptr inbounds i64, i64* %m, i64 9
+  %4 = bitcast i64* %3 to i64 (%C*)**
+  %5 = load i64 (%C*)*, i64 (%C*)** %4, align 8
+  %6 = icmp eq i64* %m, %n
+  %7 = select i1 %6, %C* %0, %C* null
+  %8 = icmp eq %C* %7, null
+  br i1 %8, label %10, label %10
+
+; <label>:9                                       ; preds = %10, %12
+  ret void
+
+; <label>:10                                      ; preds = %entry
+  %11 = getelementptr inbounds %C, %C* %7, i64 0, i32 0
+  tail call void @bar(%struct.S* %11)
+  br label %9
+
+; CHECK-LABEL: @test6(
+; CHECK: select
+}