Index: cfe/trunk/include/clang/Driver/Options.td
===================================================================
--- cfe/trunk/include/clang/Driver/Options.td
+++ cfe/trunk/include/clang/Driver/Options.td
@@ -1089,6 +1089,9 @@
 def fno_pie : Flag<["-"], "fno-pie">, Group<f_Group>;
 def fplugin_EQ : Joined<["-"], "fplugin=">, Group<f_Group>, Flags<[DriverOption]>, MetaVarName<"<dsopath>">,
   HelpText<"Load the named plugin (dynamic shared object)">;
+def fpreserve_as_comments : Flag<["-"], "fpreserve-as-comments">, Group<f_Group>;
+def fno_preserve_as_comments : Flag<["-"], "fno-preserve-as-comments">, Group<f_Group>, Flags<[CC1Option]>,
+  HelpText<"Do not preserve comments in inline assembly">;
 def fprofile_arcs : Flag<["-"], "fprofile-arcs">, Group<f_Group>;
 def fno_profile_arcs : Flag<["-"], "fno-profile-arcs">, Group<f_Group>;
 def framework : Separate<["-"], "framework">, Flags<[LinkerInput]>;
Index: cfe/trunk/include/clang/Frontend/CodeGenOptions.def
===================================================================
--- cfe/trunk/include/clang/Frontend/CodeGenOptions.def
+++ cfe/trunk/include/clang/Frontend/CodeGenOptions.def
@@ -32,6 +32,7 @@
 CODEGENOPT(CompressDebugSections, 1, 0) ///< -Wa,-compress-debug-sections
 CODEGENOPT(RelaxELFRelocations, 1, 0) ///< -Wa,--mrelax-relocations
 CODEGENOPT(AsmVerbose        , 1, 0) ///< -dA, -fverbose-asm.
+CODEGENOPT(PreserveAsmComments, 1, 1) ///< -dA, -fno-preserve-as-comments.
 CODEGENOPT(AssumeSaneOperatorNew , 1, 1) ///< implicit __attribute__((malloc)) operator new
 CODEGENOPT(Autolink          , 1, 1) ///< -fno-autolink
 CODEGENOPT(ObjCAutoRefCountExceptions , 1, 0) ///< Whether ARC should be EH-safe.
Index: cfe/trunk/lib/CodeGen/BackendUtil.cpp
===================================================================
--- cfe/trunk/lib/CodeGen/BackendUtil.cpp
+++ cfe/trunk/lib/CodeGen/BackendUtil.cpp
@@ -604,6 +604,7 @@
       CodeGenOpts.IncrementalLinkerCompatible;
   Options.MCOptions.MCFatalWarnings = CodeGenOpts.FatalWarnings;
   Options.MCOptions.AsmVerbose = CodeGenOpts.AsmVerbose;
+  Options.MCOptions.PreserveAsmComments = CodeGenOpts.PreserveAsmComments;
   Options.MCOptions.ABIName = TargetOpts.ABI;
 
   TM.reset(TheTarget->createTargetMachine(Triple, TargetOpts.CPU, FeaturesStr,
Index: cfe/trunk/lib/Driver/Tools.cpp
===================================================================
--- cfe/trunk/lib/Driver/Tools.cpp
+++ cfe/trunk/lib/Driver/Tools.cpp
@@ -4193,6 +4193,10 @@
                     true))
     CmdArgs.push_back("-fno-jump-tables");
 
+  if (!Args.hasFlag(options::OPT_fpreserve_as_comments,
+                    options::OPT_fno_preserve_as_comments, true))
+    CmdArgs.push_back("-fno-preserve-as-comments");
+
   if (Arg *A = Args.getLastArg(options::OPT_mregparm_EQ)) {
     CmdArgs.push_back("-mregparm");
     CmdArgs.push_back(A->getValue());
Index: cfe/trunk/lib/Frontend/CompilerInvocation.cpp
===================================================================
--- cfe/trunk/lib/Frontend/CompilerInvocation.cpp
+++ cfe/trunk/lib/Frontend/CompilerInvocation.cpp
@@ -544,6 +544,7 @@
       Args.hasFlag(OPT_fcoverage_mapping, OPT_fno_coverage_mapping, false);
   Opts.DumpCoverageMapping = Args.hasArg(OPT_dump_coverage_mapping);
   Opts.AsmVerbose = Args.hasArg(OPT_masm_verbose);
+  Opts.PreserveAsmComments = !Args.hasArg(OPT_fno_preserve_as_comments);
   Opts.AssumeSaneOperatorNew = !Args.hasArg(OPT_fno_assume_sane_operator_new);
   Opts.ObjCAutoRefCountExceptions = Args.hasArg(OPT_fobjc_arc_exceptions);
   Opts.CXAAtExit = !Args.hasArg(OPT_fno_use_cxa_atexit);
Index: cfe/trunk/test/CodeGen/preserve-as-comments.c
===================================================================
--- cfe/trunk/test/CodeGen/preserve-as-comments.c
+++ cfe/trunk/test/CodeGen/preserve-as-comments.c
@@ -0,0 +1,12 @@
+// RUN: %clang_cc1 -S -fno-preserve-as-comments %s -o - | FileCheck %s --check-prefix=NOASM --check-prefix=CHECK
+// RUN: %clang_cc1 -S %s -o - | FileCheck %s --check-prefix=ASM --check-prefix=CHECK
+
+// CHECK-LABEL: main
+// CHECK: #APP
+// ASM: #comment
+// NOASM-NOT: #comment
+// CHECK: #NO_APP
+int main() {
+  __asm__("/*comment*/");
+  return 0;
+}