Index: lib/Analysis/InlineCost.cpp
===================================================================
--- lib/Analysis/InlineCost.cpp
+++ lib/Analysis/InlineCost.cpp
@@ -1453,19 +1453,6 @@
   // Maximum valid cost increased in this function.
   int CostUpperBound = INT_MAX - InlineConstants::InstrCost - 1;
 
-  // Exit early for a large switch, assuming one case needs at least one
-  // instruction.
-  // FIXME: This is not true for a bit test, but ignore such case for now to
-  // save compile-time.
-  int64_t CostLowerBound =
-      std::min((int64_t)CostUpperBound,
-               (int64_t)SI.getNumCases() * InlineConstants::InstrCost + Cost);
-
-  if (CostLowerBound > Threshold && !ComputeFullInlineCost) {
-    addCost((int64_t)SI.getNumCases() * InlineConstants::InstrCost);
-    return false;
-  }
-
   unsigned JumpTableSize = 0;
   unsigned NumCaseCluster =
       TTI.getEstimatedNumberOfCaseClusters(SI, JumpTableSize);
Index: test/Transforms/Inline/X86/switch.ll
===================================================================
--- /dev/null
+++ test/Transforms/Inline/X86/switch.ll
@@ -0,0 +1,160 @@
+; RUN: opt < %s -inline -inline-threshold=1 -S -mtriple=x86_64-unknown-linux-gnu  | FileCheck %s
+; RUN: opt < %s -passes='cgscc(inline)' -inline-threshold=1 -S -mtriple=x86_64-unknown-linux-gnu | FileCheck %s
+
+define i32 @callee_range(i32 %a, i32* %P) {
+  switch i32 %a, label %sw.default [
+    i32 0, label %sw.bb0
+    i32 1000, label %sw.bb1
+    i32 2000, label %sw.bb1
+    i32 3000, label %sw.bb1
+    i32 4000, label %sw.bb1
+    i32 5000, label %sw.bb1
+    i32 6000, label %sw.bb1
+    i32 7000, label %sw.bb1
+    i32 8000, label %sw.bb1
+    i32 9000, label %sw.bb1
+  ]
+
+sw.default:
+  store volatile i32 %a, i32* %P
+  br label %return
+sw.bb0:
+  store volatile i32 %a, i32* %P
+  br label %return
+sw.bb1:
+  store volatile i32 %a, i32* %P
+  br label %return
+return:
+  ret i32 42
+}
+
+define i32 @caller_range(i32 %a, i32* %P) {
+; CHECK-LABEL: @caller_range(
+; CHECK: call i32 @callee_range
+  %r = call i32 @callee_range(i32 %a, i32* %P)
+  ret i32 %r
+}
+
+define i32 @callee_bittest(i32 %a, i32* %P) {
+  switch i32 %a, label %sw.default [
+    i32 0, label %sw.bb0
+    i32 1, label %sw.bb1
+    i32 2, label %sw.bb2
+    i32 3, label %sw.bb0
+    i32 4, label %sw.bb1
+    i32 5, label %sw.bb2
+    i32 6, label %sw.bb0
+    i32 7, label %sw.bb1
+    i32 8, label %sw.bb2
+  ]
+
+sw.default:
+  store volatile i32 %a, i32* %P
+  br label %return
+
+sw.bb0:
+  store volatile i32 %a, i32* %P
+  br label %return
+
+sw.bb1:
+  store volatile i32 %a, i32* %P
+  br label %return
+
+sw.bb2:
+  br label %return
+
+return:
+  ret i32 42
+}
+
+
+define i32 @caller_bittest(i32 %a, i32* %P) {
+; CHECK-LABEL: @caller_bittest(
+; CHECK-NOT: call i32 @callee_bittest
+  %r= call i32 @callee_bittest(i32 %a, i32* %P)
+  ret i32 %r
+}
+
+define i32 @callee_jumptable(i32 %a, i32* %P) {
+  switch i32 %a, label %sw.default [
+    i32 1001, label %sw.bb101
+    i32 1002, label %sw.bb102
+    i32 1003, label %sw.bb103
+    i32 1004, label %sw.bb104
+    i32 1005, label %sw.bb101
+    i32 1006, label %sw.bb102
+    i32 1007, label %sw.bb103
+    i32 1008, label %sw.bb104
+    i32 1009, label %sw.bb101
+    i32 1010, label %sw.bb102
+    i32 1011, label %sw.bb103
+    i32 1012, label %sw.bb104
+ ]
+
+sw.default:
+  br label %return
+
+sw.bb101:
+  store volatile i32 %a, i32* %P
+  br label %return
+
+sw.bb102:
+  store volatile i32 %a, i32* %P
+  br label %return
+
+sw.bb103:
+  store volatile i32 %a, i32* %P
+  br label %return
+
+sw.bb104:
+  store volatile i32 %a, i32* %P
+  br label %return
+
+return:
+  ret i32 42
+}
+
+define i32 @caller_jumptable(i32 %a, i32 %b, i32* %P) {
+; CHECK-LABEL: @caller_jumptable(
+; CHECK: call i32 @callee_jumptable
+  %r = call i32 @callee_jumptable(i32 %b, i32* %P)
+  ret i32 %r
+}
+
+
+define internal i32 @callee_negativeCost(i32 %t)  {
+entry:
+  switch i32 %t, label %sw.default [
+    i32 1, label %sw.bb
+    i32 0, label %sw.bb1
+    i32 42, label %sw.bb2
+    i32 43, label %sw.bb3
+  ]
+
+sw.bb:                                            ; preds = %entry
+  br label %cleanup
+
+sw.bb1:                                           ; preds = %entry
+  br label %cleanup
+
+sw.bb2:                                           ; preds = %entry
+  br label %cleanup
+
+sw.bb3:                                           ; preds = %entry
+  br label %cleanup
+
+sw.default:                                       ; preds = %entry
+  br label %cleanup
+
+cleanup:                                          ; preds = %sw.default, %sw.bb3, %sw.bb2, %sw.bb1, %sw.bb
+  %retval.0 = phi i32 [ 1, %sw.default ], [ 3, %sw.bb3 ], [ 2, %sw.bb2 ], [ 0, %sw.bb1 ], [ 0, %sw.bb ]
+  ret i32 %retval.0
+}
+
+define i32 @caller_negativeCost(i32 %t) {
+; CHECK-LABEL: @caller_negativeCost(
+; CHECK-NOT: call i32 @callee_negativeCost
+entry:
+  %call = call i32 @callee_negativeCost(i32 %t)
+  ret i32 %call
+}