diff --git a/clang/include/clang/Basic/LangOptions.def b/clang/include/clang/Basic/LangOptions.def
--- a/clang/include/clang/Basic/LangOptions.def
+++ b/clang/include/clang/Basic/LangOptions.def
@@ -295,6 +295,8 @@
              "stack protector mode")
 ENUM_LANGOPT(TrivialAutoVarInit, TrivialAutoVarInitKind, 2, TrivialAutoVarInitKind::Uninitialized,
              "trivial automatic variable initialization")
+VALUE_LANGOPT(TrivialAutoVarInitStopAfter, 32, 0,
+             "stop trivial automatic variable initialization after the specified number of instances. 0 is ignored.")
 ENUM_LANGOPT(SignedOverflowBehavior, SignedOverflowBehaviorTy, 2, SOB_Undefined,
              "signed integer overflow handling")
 
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -1828,6 +1828,8 @@
 def enable_trivial_var_init_zero : Flag<["-"], "enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang">,
   Flags<[CC1Option, CoreOption]>,
   HelpText<"Trivial automatic variable initialization to zero is only here for benchmarks, it'll eventually be removed, and I'm OK with that because I'm only using it to benchmark">;
+def ftrivial_auto_var_init_stop_after : Joined<["-"], "ftrivial-auto-var-init-stop-after=">, Group<f_Group>,
+  Flags<[CC1Option, CoreOption]>, HelpText<"Stop initializing trivial automatic stack variables after the specified number of instances">;
 def fstandalone_debug : Flag<["-"], "fstandalone-debug">, Group<f_Group>, Flags<[CoreOption]>,
   HelpText<"Emit full debug info for all types used by the program">;
 def fno_standalone_debug : Flag<["-"], "fno-standalone-debug">, Group<f_Group>, Flags<[CoreOption]>,
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -75,6 +75,8 @@
     break;
   }
   }
+  if (CGF.CGM.stopAutoInit())
+    return;
   CGF.Builder.CreateMemSet(AI, Byte, Size, AlignmentInBytes);
 }
 
diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp
--- a/clang/lib/CodeGen/CGDecl.cpp
+++ b/clang/lib/CodeGen/CGDecl.cpp
@@ -1679,11 +1679,13 @@
     case LangOptions::TrivialAutoVarInitKind::Uninitialized:
       llvm_unreachable("Uninitialized handled by caller");
     case LangOptions::TrivialAutoVarInitKind::Zero:
-      emitStoresForZeroInit(CGM, D, Loc, isVolatile, Builder);
-      break;
     case LangOptions::TrivialAutoVarInitKind::Pattern:
-      emitStoresForPatternInit(CGM, D, Loc, isVolatile, Builder);
-      break;
+      if (CGM.stopAutoInit())
+        return;
+      if (trivialAutoVarInit == LangOptions::TrivialAutoVarInitKind::Zero)
+        emitStoresForZeroInit(CGM, D, Loc, isVolatile, Builder);
+      else
+        emitStoresForPatternInit(CGM, D, Loc, isVolatile, Builder);
     }
     return;
   }
diff --git a/clang/lib/CodeGen/CodeGenModule.h b/clang/lib/CodeGen/CodeGenModule.h
--- a/clang/lib/CodeGen/CodeGenModule.h
+++ b/clang/lib/CodeGen/CodeGenModule.h
@@ -302,6 +302,7 @@
   const HeaderSearchOptions &HeaderSearchOpts; // Only used for debug info.
   const PreprocessorOptions &PreprocessorOpts; // Only used for debug info.
   const CodeGenOptions &CodeGenOpts;
+  unsigned NumAutoVarInit = 0;
   llvm::Module &TheModule;
   DiagnosticsEngine &Diags;
   const TargetInfo &Target;
@@ -1382,6 +1383,16 @@
   /// \param QT is the clang QualType of the null pointer.
   llvm::Constant *getNullPointer(llvm::PointerType *T, QualType QT);
 
+  bool stopAutoInit() {
+    unsigned StopAfter = getContext().getLangOpts().TrivialAutoVarInitStopAfter;
+    if (StopAfter) {
+      if (NumAutoVarInit >= StopAfter)
+        return true;
+      ++NumAutoVarInit;
+    }
+    return false;
+  }
+
 private:
   llvm::Constant *GetOrCreateLLVMFunction(
       StringRef MangledName, llvm::Type *Ty, GlobalDecl D, bool ForVTable,
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -3086,6 +3086,14 @@
     CmdArgs.push_back(
         Args.MakeArgString("-ftrivial-auto-var-init=" + TrivialAutoVarInit));
   }
+
+  if (Arg *A =
+          Args.getLastArg(options::OPT_ftrivial_auto_var_init_stop_after)) {
+    A->claim();
+    StringRef Val = A->getValue();
+    CmdArgs.push_back(
+        Args.MakeArgString("-ftrivial-auto-var-init-stop-after=" + Val));
+  }
 }
 
 static void RenderOpenCLOptions(const ArgList &Args, ArgStringList &CmdArgs) {
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -3256,6 +3256,11 @@
       Diags.Report(diag::err_drv_invalid_value) << A->getAsString(Args) << Val;
   }
 
+  if (Arg *A = Args.getLastArg(OPT_ftrivial_auto_var_init_stop_after)) {
+    unsigned Val = (unsigned)std::stoi(A->getValue());
+    Opts.TrivialAutoVarInitStopAfter = Val;
+  }
+
   // Parse -fsanitize= arguments.
   parseSanitizerKinds("-fsanitize=", Args.getAllArgValues(OPT_fsanitize_EQ),
                       Diags, Opts.Sanitize);
diff --git a/clang/test/CodeGenCXX/auto-var-init-stop-after.cpp b/clang/test/CodeGenCXX/auto-var-init-stop-after.cpp
new file mode 100644
--- /dev/null
+++ b/clang/test/CodeGenCXX/auto-var-init-stop-after.cpp
@@ -0,0 +1,29 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -ftrivial-auto-var-init=pattern -ftrivial-auto-var-init-stop-after=2 %s -emit-llvm -o - | FileCheck %s -check-prefix=PATTERN-STOP-AFTER-2
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -ftrivial-auto-var-init=pattern -ftrivial-auto-var-init-stop-after=3 %s -emit-llvm -o - | FileCheck %s -check-prefix=PATTERN-STOP-AFTER-3
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -ftrivial-auto-var-init=pattern -ftrivial-auto-var-init-stop-after=4 %s -emit-llvm -o - | FileCheck %s -check-prefix=PATTERN-STOP-AFTER-4
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -ftrivial-auto-var-init=zero -ftrivial-auto-var-init-stop-after=2 %s -emit-llvm -o - | FileCheck %s -check-prefix=ZERO-STOP-AFTER-2
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -ftrivial-auto-var-init=zero -ftrivial-auto-var-init-stop-after=3 %s -emit-llvm -o - | FileCheck %s -check-prefix=ZERO-STOP-AFTER-3
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -ftrivial-auto-var-init=zero -ftrivial-auto-var-init-stop-after=4 %s -emit-llvm -o - | FileCheck %s -check-prefix=ZERO-STOP-AFTER-4
+
+#define ARRLEN 10
+
+typedef struct {
+  int i;
+  char c;
+} S;
+
+int foo(unsigned n) {
+  long a = 888;
+  S arr1[ARRLEN];
+  void *p;
+  p = __builtin_alloca(sizeof(unsigned long long) * n);
+  // PATTERN-STOP-AFTER-2-NOT: store i8* inttoptr (i64 -6148914691236517206 to i8*), i8** %p, align 8
+  // PATTERN-STOP-AFTER-3: store i8* inttoptr (i64 -6148914691236517206 to i8*), i8** %p, align 8
+  // PATTERN-STOP-AFTER-3-NOT: call void @llvm.memset.p0i8.i64(i8* align 16 %2, i8 -86, i64 %mul, i1 false)
+  // PATTERN-STOP-AFTER-4: call void @llvm.memset.p0i8.i64(i8* align 16 %2, i8 -86, i64 %mul, i1 false)
+  // ZERO-STOP-AFTER-2-NOT: store i8* null, i8** %p, align 8
+  // ZERO-STOP-AFTER-3: store i8* null, i8** %p, align 8
+  // ZERO-STOP-AFTER-3-NOT: void @llvm.memset.p0i8.i64(i8* align 16 %2, i8 0, i64 %mul, i1 false)
+  // ZERO-STOP-AFTER-4: void @llvm.memset.p0i8.i64(i8* align 16 %2, i8 0, i64 %mul, i1 false)
+  return 0;
+}
diff --git a/clang/test/Driver/clang_f_opts.c b/clang/test/Driver/clang_f_opts.c
--- a/clang/test/Driver/clang_f_opts.c
+++ b/clang/test/Driver/clang_f_opts.c
@@ -571,8 +571,8 @@
 // CHECK-RECORD-GCC-SWITCHES-ESCAPED: "-record-command-line" "{{.+}}with\\ spaces{{.+}}"
 
 // RUN: %clang -### -S -ftrivial-auto-var-init=uninitialized %s 2>&1 | FileCheck -check-prefix=CHECK-TRIVIAL-UNINIT %s
-// RUN: %clang -### -S -ftrivial-auto-var-init=pattern %s 2>&1 | FileCheck -check-prefix=CHECK-TRIVIAL-PATTERN %s
-// RUN: %clang -### -S -ftrivial-auto-var-init=zero -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang %s 2>&1 | FileCheck -check-prefix=CHECK-TRIVIAL-ZERO-GOOD %s
+// RUN: %clang -### -S -ftrivial-auto-var-init=pattern -ftrivial-auto-var-init-stop-after=1 %s 2>&1 | FileCheck -check-prefix=CHECK-TRIVIAL-PATTERN %s
+// RUN: %clang -### -S -ftrivial-auto-var-init=zero -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang -ftrivial-auto-var-init-stop-after=1 %s 2>&1 | FileCheck -check-prefix=CHECK-TRIVIAL-ZERO-GOOD %s
 // RUN: %clang -### -S -ftrivial-auto-var-init=zero %s 2>&1 | FileCheck -check-prefix=CHECK-TRIVIAL-ZERO-BAD %s
 // CHECK-TRIVIAL-UNINIT-NOT: hasn't been enabled
 // CHECK-TRIVIAL-PATTERN-NOT: hasn't been enabled