3 files changed, 13 insertions, 3 deletions
diff --git a/lib/CodeGen/CGCall.cpp b/lib/CodeGen/CGCall.cpp
index 60a138c419..cc8dbcb1df 100644
--- a/lib/CodeGen/CGCall.cpp
+++ b/lib/CodeGen/CGCall.cpp
@@ -755,10 +755,10 @@ void CodeGenModule::ConstructAttributeList(const CGFunctionInfo &FI,
   if (RetAttrs)
     PAL.push_back(llvm::AttributeWithIndex::get(0, RetAttrs));
 
-  // FIXME: we need to honor command line settings also.
-  // FIXME: RegParm should be reduced in case of nested functions and/or global
-  // register variable.
+  // FIXME: RegParm should be reduced in case of global register variable.
   signed RegParm = FI.getRegParm();
+  if (!RegParm)
+    RegParm = CodeGenOpts.NumRegisterParameters;
 
   unsigned PointerWidth = getContext().Target.getPointerWidth(0);
   for (CGFunctionInfo::const_arg_iterator it = FI.arg_begin(),
diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index f0a142fe0e..fdc2b82cb8 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -1012,6 +1012,11 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
 
   // LLVM Code Generator Options.
 
+  if (Arg *A = Args.getLastArg(options::OPT_mregparm_EQ)) {
+    CmdArgs.push_back("-mregparm");
+    CmdArgs.push_back(A->getValue(Args));
+  }
+
   // FIXME: Set --enable-unsafe-fp-math.
   if (Args.hasFlag(options::OPT_fno_omit_frame_pointer,
                    options::OPT_fomit_frame_pointer))
diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index 6fc7373822..3108477e3a 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -202,6 +202,10 @@ static void CodeGenOptsToArgs(const CodeGenOptions &Opts,
     Res.push_back("-fobjc-dispatch-method=non-legacy");
     break;
   }
+  if (Opts.NumRegisterParameters) {
+    Res.push_back("-mregparm");
+    Res.push_back(llvm::utostr(Opts.NumRegisterParameters));
+  }
   if (Opts.RelaxAll)
     Res.push_back("-mrelax-all");
   if (Opts.SoftFloat)
@@ -928,6 +932,7 @@ static void ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.NoInfsFPMath = Opts.NoNaNsFPMath = Args.hasArg(OPT_cl_finite_math_only)||
                                           Args.hasArg(OPT_cl_fast_relaxed_math);
   Opts.NoZeroInitializedInBSS = Args.hasArg(OPT_mno_zero_initialized_in_bss);
+  Opts.NumRegisterParameters = Args.getLastArgIntValue(OPT_mregparm, 0, Diags);
   Opts.RelaxAll = Args.hasArg(OPT_mrelax_all);
   Opts.OmitLeafFramePointer = Args.hasArg(OPT_momit_leaf_frame_pointer);
   Opts.SoftFloat = Args.hasArg(OPT_msoft_float);