diff --git a/llvm/test/Transforms/BlockExtractor/extract-blocks.ll b/llvm/test/Transforms/BlockExtractor/extract-blocks.ll
@@ -0,0 +1,43 @@
+; RUN: echo 'foo bb9' > %t
+; RUN: echo 'foo bb20' >> %t
+; RUN: opt -S -extract-blocks -extract-blocks-file=%t %s | FileCheck %s --check-prefix=CHECK-NO-ERASE
+; RUN: opt -S -extract-blocks -extract-blocks-file=%t -extract-blocks-erase-funcs %s | FileCheck %s --check-prefix=CHECK-ERASE
+
+; CHECK-NO-ERASE: @foo(
+; CHECK-NO-ERASE: @foo_bb9(
+; CHECK-NO-ERASE: @foo_bb20(
+; CHECK-ERASE-NOT: @foo(
+; CHECK-ERASE: @foo_bb9(
+; CHECK-ERASE: @foo_bb20(
+define i32 @foo(i32 %arg, i32 %arg1) {
+bb:
+  %tmp5 = icmp sgt i32 %arg, 0
+  %tmp8 = icmp sgt i32 %arg1, 0
+  %or.cond = and i1 %tmp5, %tmp8
+  br i1 %or.cond, label %bb9, label %bb14
+
+bb9:                                              ; preds = %bb
+  %tmp12 = shl i32 %arg1, 2
+  %tmp13 = add nsw i32 %tmp12, %arg
+  br label %bb30
+
+bb14:                                             ; preds = %bb
+  %0 = and i32 %arg1, %arg
+  %1 = icmp slt i32 %0, 0
+  br i1 %1, label %bb20, label %bb26
+
+bb20:                                             ; preds = %bb14
+  %tmp22 = mul nsw i32 %arg, 3
+  %tmp24 = sdiv i32 %arg1, 6
+  %tmp25 = add nsw i32 %tmp24, %tmp22
+  br label %bb30
+
+bb26:                                             ; preds = %bb14
+  %tmp29 = sub nsw i32 %arg, %arg1
+  br label %bb30
+
+bb30:                                             ; preds = %bb26, %bb20, %bb9
+  %tmp.0 = phi i32 [ %tmp13, %bb9 ], [ %tmp25, %bb20 ], [ %tmp29, %bb26 ]
+  ret i32 %tmp.0
+}
+
diff --git a/llvm/test/Transforms/BlockExtractor/invalid-block.ll b/llvm/test/Transforms/BlockExtractor/invalid-block.ll
@@ -0,0 +1,9 @@
+; RUN: echo 'bar invalidbb' > %t
+; RUN: not opt -S -extract-blocks -extract-blocks-file=%t %s 2>&1 | FileCheck %s
+
+; CHECK: Invalid block
+define void @bar() {
+bb:
+  ret void
+}
+
diff --git a/llvm/test/Transforms/BlockExtractor/invalid-function.ll b/llvm/test/Transforms/BlockExtractor/invalid-function.ll
@@ -0,0 +1,9 @@
+; RUN: echo 'foo bb' > %t
+; RUN: not opt -S -extract-blocks -extract-blocks-file=%t %s 2>&1 | FileCheck %s
+
+; CHECK: Invalid function
+define void @bar() {
+bb:
+  ret void
+}
+
diff --git a/llvm/test/tools/llvm-extract/extract-block.ll b/llvm/test/tools/llvm-extract/extract-block.ll
@@ -0,0 +1,29 @@
+; RUN: llvm-extract -S -bb foo:bb4 %s | FileCheck %s
+
+; CHECK: @foo_bb4
+; CHECK: %tmp5
+define i32 @foo(i32 %arg) {
+bb:
+  %tmp = alloca i32, align 4
+  %tmp1 = alloca i32, align 4
+  store i32 %arg, i32* %tmp1, align 4
+  %tmp2 = load i32, i32* %tmp1, align 4
+  %tmp3 = icmp sgt i32 %tmp2, 0
+  br i1 %tmp3, label %bb4, label %bb7
+
+bb4:                                              ; preds = %bb
+  %tmp5 = load i32, i32* %tmp1, align 4
+  %tmp6 = add nsw i32 %tmp5, 1
+  store i32 %tmp6, i32* %tmp1, align 4
+  store i32 %tmp6, i32* %tmp, align 4
+  br label %bb8
+
+bb7:                                              ; preds = %bb
+  store i32 0, i32* %tmp, align 4
+  br label %bb8
+
+bb8:                                              ; preds = %bb7, %bb4
+  %tmp9 = load i32, i32* %tmp, align 4
+  ret i32 %tmp9
+}
+
diff --git a/llvm/test/tools/llvm-extract/extract-invalid-block.ll b/llvm/test/tools/llvm-extract/extract-invalid-block.ll
@@ -0,0 +1,28 @@
+; RUN: not llvm-extract -S -bb foo:invalidbb %s 2>&1 | FileCheck %s
+
+; CHECK: function foo doesn't contain a basic block named 'invalidbb'!
+define i32 @foo(i32 %arg) {
+bb:
+  %tmp = alloca i32, align 4
+  %tmp1 = alloca i32, align 4
+  store i32 %arg, i32* %tmp1, align 4
+  %tmp2 = load i32, i32* %tmp1, align 4
+  %tmp3 = icmp sgt i32 %tmp2, 0
+  br i1 %tmp3, label %bb4, label %bb7
+
+bb4:                                              ; preds = %bb
+  %tmp5 = load i32, i32* %tmp1, align 4
+  %tmp6 = add nsw i32 %tmp5, 1
+  store i32 %tmp6, i32* %tmp1, align 4
+  store i32 %tmp6, i32* %tmp, align 4
+  br label %bb8
+
+bb7:                                              ; preds = %bb
+  store i32 0, i32* %tmp, align 4
+  br label %bb8
+
+bb8:                                              ; preds = %bb7, %bb4
+  %tmp9 = load i32, i32* %tmp, align 4
+  ret i32 %tmp9
+}
+
diff --git a/llvm/test/tools/llvm-extract/extract-multiple-blocks.ll b/llvm/test/tools/llvm-extract/extract-multiple-blocks.ll
@@ -0,0 +1,29 @@
+; RUN: llvm-extract -S -bb foo:bb4 -bb foo:bb7 %s | FileCheck %s
+
+; CHECK: @foo_bb4
+; CHECK: @foo_bb7
+define i32 @foo(i32 %arg) {
+bb:
+  %tmp = alloca i32, align 4
+  %tmp1 = alloca i32, align 4
+  store i32 %arg, i32* %tmp1, align 4
+  %tmp2 = load i32, i32* %tmp1, align 4
+  %tmp3 = icmp sgt i32 %tmp2, 0
+  br i1 %tmp3, label %bb4, label %bb7
+
+bb4:                                              ; preds = %bb
+  %tmp5 = load i32, i32* %tmp1, align 4
+  %tmp6 = add nsw i32 %tmp5, 1
+  store i32 %tmp6, i32* %tmp1, align 4
+  store i32 %tmp6, i32* %tmp, align 4
+  br label %bb8
+
+bb7:                                              ; preds = %bb
+  store i32 0, i32* %tmp, align 4
+  br label %bb8
+
+bb8:                                              ; preds = %bb7, %bb4
+  %tmp9 = load i32, i32* %tmp, align 4
+  ret i32 %tmp9
+}
+
diff --git a/llvm/tools/bugpoint/ExtractFunction.cpp b/llvm/tools/bugpoint/ExtractFunction.cpp
@@ -383,10 +383,16 @@ BugDriver::extractMappedBlocksFromModule(const std::vector<BasicBlock *> &BBs,
   }
   DiscardTemp Discard{*Temp};
 
+  // Extract all of the blocks except the ones in BBs.
+  SmallVector<BasicBlock *, 32> BlocksToExtract;
+  for (Function &F : *M)
+    for (BasicBlock &BB : F)
+      // Check if this block is going to be extracted.
+      if (std::find(BBs.begin(), BBs.end(), &BB) == BBs.end())
+        BlocksToExtract.push_back(&BB);
+
   raw_fd_ostream OS(Temp->FD, /*shouldClose*/ false);
-  for (std::vector<BasicBlock *>::const_iterator I = BBs.begin(), E = BBs.end();
-       I != E; ++I) {
-    BasicBlock *BB = *I;
+  for (BasicBlock *BB : BBs) {
     // If the BB doesn't have a name, give it one so we have something to key
     // off of.
     if (!BB->hasName())

diff --git a/llvm/tools/llvm-extract/llvm-extract.cpp b/llvm/tools/llvm-extract/llvm-extract.cpp
@@ -67,6 +67,12 @@ ExtractRegExpFuncs("rfunc", cl::desc("Specify function(s) to extract using a "
                                      "regular expression"),
                    cl::ZeroOrMore, cl::value_desc("rfunction"));
 
+// ExtractBlocks - The blocks to extract from the module.
+static cl::list<std::string>
+    ExtractBlocks("bb",
+                  cl::desc("Specify <function, basic block> pairs to extract"),
+                  cl::ZeroOrMore, cl::value_desc("function:bb"));
+
 // ExtractAlias - The alias to extract from the module.
 static cl::list<std::string>
 ExtractAliases("alias", cl::desc("Specify alias to extract"),
@@ -228,6 +234,32 @@ int main(int argc, char **argv) {
     }
   }
 
+  // Figure out which BasicBlocks we should extract.
+  SmallVector<BasicBlock *, 4> BBs;
+  for (StringRef StrPair : ExtractBlocks) {
+    auto BBInfo = StrPair.split(':');
+    // Get the function.
+    Function *F = M->getFunction(BBInfo.first);
+    if (!F) {
+      errs() << argv[0] << ": program doesn't contain a function named '"
+             << BBInfo.first << "'!\n";
+      return 1;
+    }
+    // Do not materialize this function.
+    GVs.insert(F);
+    // Get the basic block.
+    auto Res = llvm::find_if(*F, [&](const BasicBlock &BB) {
+      return BB.getName().equals(BBInfo.second);
+    });
+    if (Res == F->end()) {
+      errs() << argv[0] << ": function " << F->getName()
+             << " doesn't contain a basic block named '" << BBInfo.second
+             << "'!\n";
+      return 1;
+    }
+    BBs.push_back(&*Res);
+  }
+
   // Use *argv instead of argv[0] to work around a wrong GCC warning.
   ExitOnError ExitOnErr(std::string(*argv) + ": error reading input: ");
 
@@ -286,6 +318,14 @@ int main(int argc, char **argv) {
     ExitOnErr(M->materializeAll());
   }
 
+  // Extract the specified basic blocks from the module and erase the existing
+  // functions.
+  if (!ExtractBlocks.empty()) {
+    legacy::PassManager PM;
+    PM.add(createBlockExtractorPass(BBs, true));
+    PM.run(*M);
+  }
+
   // In addition to deleting all other functions, we also want to spiff it
   // up a little bit.  Do this now.
   legacy::PassManager Passes;