Index: docs/UsersManual.rst
===================================================================
--- docs/UsersManual.rst
+++ docs/UsersManual.rst
@@ -1140,6 +1140,16 @@
    This option restricts the generated code to use general registers
    only. This only applies to the AArch64 architecture.
 
+.. option:: -mcompact-branches=[values]
+
+   Control the usage of compact branches for MIPSR6.
+
+   Valid values are: ``never``, ``optimal`` and ``always``.
+   The default value is ``optimal`` which generates compact branches
+   when a delay slot cannot be filled. ``never`` disables the usage of
+   compact branches and ``always`` generates compact branches whenever
+   possible.
+
 **-f[no-]max-type-align=[number]**
    Instruct the code generator to not enforce a higher alignment than the given
    number (of bytes) when accessing memory via an opaque pointer or reference.
Index: include/clang/Basic/DiagnosticDriverKinds.td
===================================================================
--- include/clang/Basic/DiagnosticDriverKinds.td
+++ include/clang/Basic/DiagnosticDriverKinds.td
@@ -238,6 +238,9 @@
 def warn_target_unsupported_nanlegacy : Warning<
   "ignoring '-mnan=legacy' option because the '%0' architecture does not support it">,
   InGroup<UnsupportedNan>;
+def warn_target_unsupported_compact_branches : Warning<
+  "ignoring '-mcompact-branches=' option because the '%0' architecture does not"
+  " support it">, InGroup<UnsupportedCB>;
 
 def warn_drv_unable_to_find_directory_expected : Warning<
   "unable to find %0 directory, expected to be in '%1'">,
Index: include/clang/Basic/DiagnosticGroups.td
===================================================================
--- include/clang/Basic/DiagnosticGroups.td
+++ include/clang/Basic/DiagnosticGroups.td
@@ -56,6 +56,7 @@
 def DoublePromotion : DiagGroup<"double-promotion">;
 def EnumTooLarge : DiagGroup<"enum-too-large">;
 def UnsupportedNan : DiagGroup<"unsupported-nan">;
+def UnsupportedCB : DiagGroup<"unsupported-cb">;
 def NonLiteralNullConversion : DiagGroup<"non-literal-null-conversion">;
 def NullConversion : DiagGroup<"null-conversion">;
 def ImplicitConversionFloatingPointToBool :
Index: include/clang/Driver/Options.td
===================================================================
--- include/clang/Driver/Options.td
+++ include/clang/Driver/Options.td
@@ -1621,6 +1621,7 @@
 def mcheck_zero_division : Flag<["-"], "mcheck-zero-division">, Group<m_Group>;
 def mno_check_zero_division : Flag<["-"], "mno-check-zero-division">,
                               Group<m_Group>;
+def mcompact_branches_EQ : Joined<["-"], "mcompact-branches=">, Group<m_Group>;
 def mdsp : Flag<["-"], "mdsp">, Group<m_Group>;
 def mno_dsp : Flag<["-"], "mno-dsp">, Group<m_Group>;
 def mdspr2 : Flag<["-"], "mdspr2">, Group<m_Group>;
Index: lib/Driver/Tools.h
===================================================================
--- lib/Driver/Tools.h
+++ lib/Driver/Tools.h
@@ -291,6 +291,7 @@
 };
 
 NanEncoding getSupportedNanEncoding(StringRef &CPU);
+bool hasCompactBranches(StringRef &CPU);
 void getMipsCPUAndABI(const llvm::opt::ArgList &Args,
                       const llvm::Triple &Triple, StringRef &CPUName,
                       StringRef &ABIName);
Index: lib/Driver/Tools.cpp
===================================================================
--- lib/Driver/Tools.cpp
+++ lib/Driver/Tools.cpp
@@ -1436,6 +1436,20 @@
     CmdArgs.push_back(Args.MakeArgString("-mips-ssection-threshold=" + v));
     A->claim();
   }
+
+  if (Arg *A = Args.getLastArg(options::OPT_mcompact_branches_EQ)) {
+    StringRef Val = StringRef(A->getValue());
+    if (mips::hasCompactBranches(CPUName)) {
+      if (Val == "never" || Val == "always" || Val == "optimal") {
+        CmdArgs.push_back("-mllvm");
+        CmdArgs.push_back(Args.MakeArgString("-mips-compact-branches=" + Val));
+
+      } else
+        D.Diag(diag::err_drv_unsupported_option_argument)
+            << A->getOption().getName() << Val;
+    } else
+      D.Diag(diag::warn_target_unsupported_compact_branches) << CPUName;
+  }
 }
 
 /// getPPCTargetCPU - Get the (LLVM) name of the PowerPC cpu we are targeting.
@@ -7065,6 +7079,15 @@
       .Default(NanLegacy);
 }
 
+bool mips::hasCompactBranches(StringRef &CPU) {
+  // mips32r6 and mips64r6 have compact branches.
+
+  return (bool)llvm::StringSwitch<int>(CPU)
+      .Case("mips32r6", true)
+      .Case("mips64r6", true)
+      .Default(false);
+}
+
 bool mips::hasMipsAbiArg(const ArgList &Args, const char *Value) {
   Arg *A = Args.getLastArg(options::OPT_mabi_EQ);
   return A && (A->getValue() == StringRef(Value));
Index: test/Driver/mips-features.c
===================================================================
--- test/Driver/mips-features.c
+++ test/Driver/mips-features.c
@@ -116,6 +116,24 @@
 // RUN:   | FileCheck --check-prefix=CHECK-NANLEGACY %s
 // CHECK-NANLEGACY: "-target-feature" "-nan2008"
 //
+// -mcompact-branches=never
+// RUN: %clang -target mips-linux-gnu -march=mips32r6 -### -c %s \
+// RUN:     -mcompact-branches=never 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-CBNEVER %s
+// CHECK-CBNEVER: "-mllvm" "-mips-compact-branches=never"
+//
+// -mcompact-branches=optimal
+// RUN: %clang -target mips-linux-gnu -march=mips32r6 -### -c %s \
+// RUN:     -mcompact-branches=optimal 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-CBOPTIMAL %s
+// CHECK-CBOPTIMAL: "-mllvm" "-mips-compact-branches=optimal"
+//
+// -mcompact-branches=always
+// RUN: %clang -target mips-linux-gnu -march=mips32r6 -### -c %s \
+// RUN:     -mcompact-branches=always 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-CBALWAYS %s
+// CHECK-CBALWAYS: "-mllvm" "-mips-compact-branches=always"
+//
 // -mxgot
 // RUN: %clang -target mips-linux-gnu -### -c %s \
 // RUN:     -mno-xgot -mxgot 2>&1 \