diff --git a/clang/include/clang/Driver/CC1Options.td b/clang/include/clang/Driver/CC1Options.td
index 8729512..75f8aa6 100644
--- a/clang/include/clang/Driver/CC1Options.td
+++ b/clang/include/clang/Driver/CC1Options.td
@@ -307,8 +307,6 @@
   HelpText<"Limit float precision to the given value">;
 def split_stacks : Flag<["-"], "split-stacks">,
   HelpText<"Try to use a split stack if possible.">;
-def mno_zero_initialized_in_bss : Flag<["-"], "mno-zero-initialized-in-bss">,
-  HelpText<"Do not put zero initialized data in the BSS">;
 def mregparm : Separate<["-"], "mregparm">,
   HelpText<"Limit the number of registers available for integer arguments">;
 def msmall_data_limit : Separate<["-"], "msmall-data-limit">,
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index d030468..e636ee6 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -1589,7 +1589,6 @@
 def fno_verbose_asm : Flag<["-"], "fno-verbose-asm">, Group<f_Group>, Flags<[CC1Option]>;
 def fno_working_directory : Flag<["-"], "fno-working-directory">, Group<f_Group>;
 def fno_wrapv : Flag<["-"], "fno-wrapv">, Group<f_Group>;
-def fno_zero_initialized_in_bss : Flag<["-"], "fno-zero-initialized-in-bss">, Group<f_Group>;
 def fobjc_arc : Flag<["-"], "fobjc-arc">, Group<f_Group>, Flags<[CC1Option]>,
   HelpText<"Synthesize retain and release calls for Objective-C pointers">;
 def fno_objc_arc : Flag<["-"], "fno-objc-arc">, Group<f_Group>;
@@ -1926,7 +1925,7 @@
   HelpText<"Treat signed integer overflow as two's complement">;
 def fwritable_strings : Flag<["-"], "fwritable-strings">, Group<f_Group>, Flags<[CC1Option]>,
   HelpText<"Store string literals as writable data">;
-def fzero_initialized_in_bss : Flag<["-"], "fzero-initialized-in-bss">, Group<f_Group>;
+defm zero_initialized_in_bss : OptOutFFlag<"zero-initialized-in-bss", "", "Don't place zero initialized data in BSS">;
 defm function_sections : OptInFFlag<"function-sections", "Place each function in its own section">;
 def fbasic_block_sections_EQ : Joined<["-"], "fbasic-block-sections=">, Group<f_Group>,
   Flags<[CC1Option, CC1AsOption]>,
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index e6dd6ce..a0d638e7 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -4556,8 +4556,8 @@
   CmdArgs.push_back(FPKeepKindStr);
 
   if (!Args.hasFlag(options::OPT_fzero_initialized_in_bss,
-                    options::OPT_fno_zero_initialized_in_bss))
-    CmdArgs.push_back("-mno-zero-initialized-in-bss");
+                    options::OPT_fno_zero_initialized_in_bss, true))
+    CmdArgs.push_back("-fno-zero-initialized-in-bss");
 
   bool OFastEnabled = isOptimizationLevelFast(Args);
   // If -Ofast is the optimization level, then -fstrict-aliasing should be
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index e12931a..821e40c 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -942,7 +942,7 @@
   Opts.StrictFloatCastOverflow =
       !Args.hasArg(OPT_fno_strict_float_cast_overflow);
 
-  Opts.NoZeroInitializedInBSS = Args.hasArg(OPT_mno_zero_initialized_in_bss);
+  Opts.NoZeroInitializedInBSS = Args.hasArg(OPT_fno_zero_initialized_in_bss);
   Opts.NumRegisterParameters = getLastArgIntValue(Args, OPT_mregparm, 0, Diags);
   Opts.NoExecStack = Args.hasArg(OPT_mno_exec_stack);
   Opts.SmallDataLimit =
diff --git a/clang/test/Driver/fzero-initialized-in-bss.c b/clang/test/Driver/fzero-initialized-in-bss.c
new file mode 100644
index 0000000..34a1dc9
--- /dev/null
+++ b/clang/test/Driver/fzero-initialized-in-bss.c
@@ -0,0 +1,8 @@
+// RUN: %clang -### %s -c -fzero-initialized-in-bss 2>&1 | FileCheck %s --check-prefix=NO
+// RUN: %clang -### %s -c 2>&1 | FileCheck %s --check-prefix=NO
+
+// NO-NOT: -fno-zero-initialized-in-bss
+
+// RUN: %clang -### %s -c -fzero-initialized-in-bss -fno-zero-initialized-in-bss 2>&1 | FileCheck %s
+
+// CHECK: -fno-zero-initialized-in-bss
diff --git a/llvm/test/CodeGen/X86/zero-initialized-in-bss.ll b/llvm/test/CodeGen/X86/zero-initialized-in-bss.ll
new file mode 100644
index 0000000..2feee54
--- /dev/null
+++ b/llvm/test/CodeGen/X86/zero-initialized-in-bss.ll
@@ -0,0 +1,16 @@
+; RUN: llc < %s -mtriple=x86_64 | FileCheck %s --check-prefix=BSS
+
+; BSS:      .bss
+; BSS-NEXT: .globl a
+; BSS:      .section .tbss,"awT",@nobits
+; BSS-NEXT: .globl b
+
+; RUN: llc < %s -mtriple=x86_64 -nozero-initialized-in-bss | FileCheck %s --check-prefix=DATA
+
+; DATA:      .data
+; DATA-NEXT: .globl a
+; DATA:      .section .tdata,"awT",@progbits
+; DATA-NEXT: .globl b
+
+@a = global i32 0
+@b = thread_local global i32 0