diff --git a/llvm/lib/Transforms/IPO/PartialInlining.cpp b/llvm/lib/Transforms/IPO/PartialInlining.cpp
--- a/llvm/lib/Transforms/IPO/PartialInlining.cpp
+++ b/llvm/lib/Transforms/IPO/PartialInlining.cpp
@@ -50,6 +50,7 @@
 #include "llvm/Transforms/Utils/Cloning.h"
 #include "llvm/Transforms/Utils/CodeExtractor.h"
 #include "llvm/Transforms/Utils/ValueMapper.h"
+#include "llvm/Transforms/Utils/BasicBlockUtils.h"
 #include <algorithm>
 #include <cassert>
 #include <cstdint>
@@ -1440,6 +1441,13 @@
     if (CurrFunc->use_empty())
       continue;
 
+    // Try to eliminate unreachable blocks in the function, having unreachable
+    // blocks leads to incorrect costing because while evaluating the costs
+    // incase of outlining a function, such unreachable basic blocks might be
+    // taken into consideration, but the code extractor simply eliminates them
+    // while the outlined function is being constructed.
+    Changed |= EliminateUnreachableBlocks(*CurrFunc);
+
     std::pair<bool, Function *> Result = unswitchFunction(*CurrFunc);
     if (Result.second)
       Worklist.push_back(Result.second);
diff --git a/llvm/test/Transforms/PartialInlining/unreachable_basic_block.ll b/llvm/test/Transforms/PartialInlining/unreachable_basic_block.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/Transforms/PartialInlining/unreachable_basic_block.ll
@@ -0,0 +1,29 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -passes=partial-inliner -S < %s | FileCheck %s
+declare i1 @llvm.public.type.test(ptr, metadata)
+
+define void @dummy() {
+; CHECK-LABEL: @dummy(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br i1 false, label [[WHILE_END:%.*]], label [[WHILE_BODY:%.*]]
+; CHECK:       while.body:
+; CHECK-NEXT:    call void @dummy.1.while.body()
+; CHECK-NEXT:    br label [[WHILE_END]]
+; CHECK:       while.end:
+; CHECK-NEXT:    ret void
+;
+entry:
+  br i1 false, label %while.end, label %while.body
+
+while.body:                                       ; preds = %entry
+  call void @dummy()
+  br label %while.end
+
+unreachable.block:               ; No predecessors!
+  %0 = tail call i1 @llvm.public.type.test(ptr null, metadata !"test-function")
+  %result = getelementptr ptr, ptr null, i64 1
+  br label %while.end
+
+while.end:                                        ; preds = %unreachable.block, %while.body, %entry
+  ret void
+}