Index: llvm/include/llvm/MC/MCAsmInfo.h
===================================================================
--- llvm/include/llvm/MC/MCAsmInfo.h
+++ llvm/include/llvm/MC/MCAsmInfo.h
@@ -16,6 +16,7 @@
 #define LLVM_MC_MCASMINFO_H
 
 #include "llvm/ADT/StringRef.h"
+#include "llvm/IR/InlineAsm.h"
 #include "llvm/MC/MCDirectives.h"
 #include "llvm/MC/MCTargetOptions.h"
 #include <vector>
@@ -565,7 +566,13 @@
   const char *getCode16Directive() const { return Code16Directive; }
   const char *getCode32Directive() const { return Code32Directive; }
   const char *getCode64Directive() const { return Code64Directive; }
+  // Default assembler dialect for AsmParser and AsmWriter.
   unsigned getAssemblerDialect() const { return AssemblerDialect; }
+  // Allow overriding default dialect for inline assembler.
+  virtual unsigned getInlineAsmDialect(InlineAsm::AsmDialect asmDialect) const {
+    return getAssemblerDialect();
+  }
+
   bool doesAllowAtInName() const { return AllowAtInName; }
   bool doesAllowSymbolAtNameStart() const { return AllowSymbolAtNameStart; }
   bool supportsNameQuoting() const { return SupportsQuotedNames; }
Index: llvm/lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp
===================================================================
--- llvm/lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp
+++ llvm/lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp
@@ -153,7 +153,7 @@
   if (!TAP)
     report_fatal_error("Inline asm not supported by this streamer because"
                        " we don't have an asm parser for this target\n");
-  Parser->setAssemblerDialect(Dialect);
+  Parser->setAssemblerDialect(MAI->getInlineAsmDialect(Dialect));
   Parser->setTargetParser(*TAP.get());
   // Enable lexing Masm binary and hex integer literals in intel inline
   // assembly.
@@ -543,7 +543,7 @@
   raw_svector_ostream OS(StringData);
 
   // The variant of the current asmprinter.
-  int AsmPrinterVariant = MAI->getAssemblerDialect();
+  int AsmPrinterVariant = MAI->getInlineAsmDialect(MI->getInlineAsmDialect());
   AsmPrinter *AP = const_cast<AsmPrinter*>(this);
   if (MI->getInlineAsmDialect() == InlineAsm::AD_ATT)
     EmitGCCInlineAsmStr(AsmStr, MI, MMI, AsmPrinterVariant, AP, LocCookie, OS);
Index: llvm/lib/Object/ModuleSymbolTable.cpp
===================================================================
--- llvm/lib/Object/ModuleSymbolTable.cpp
+++ llvm/lib/Object/ModuleSymbolTable.cpp
@@ -119,7 +119,7 @@
 
   // Module-level inline asm is assumed to use At&t syntax (see
   // AsmPrinter::doInitialization()).
-  Parser->setAssemblerDialect(InlineAsm::AD_ATT);
+  Parser->setAssemblerDialect(MAI->getInlineAsmDialect(InlineAsm::AD_ATT));
 
   Parser->setTargetParser(*TAP);
   if (Parser->Run(false))
Index: llvm/lib/Target/X86/MCTargetDesc/X86MCAsmInfo.h
===================================================================
--- llvm/lib/Target/X86/MCTargetDesc/X86MCAsmInfo.h
+++ llvm/lib/Target/X86/MCTargetDesc/X86MCAsmInfo.h
@@ -25,6 +25,7 @@
 
 public:
   explicit X86MCAsmInfoDarwin(const Triple &Triple);
+  unsigned getInlineAsmDialect(InlineAsm::AsmDialect asmDialect) const override;
 };
 
 struct X86_64MCAsmInfoDarwin : public X86MCAsmInfoDarwin {
@@ -39,6 +40,7 @@
 
 public:
   explicit X86ELFMCAsmInfo(const Triple &Triple);
+  unsigned getInlineAsmDialect(InlineAsm::AsmDialect asmDialect) const override;
 };
 
 class X86MCAsmInfoMicrosoft : public MCAsmInfoMicrosoft {
@@ -46,6 +48,7 @@
 
 public:
   explicit X86MCAsmInfoMicrosoft(const Triple &Triple);
+  unsigned getInlineAsmDialect(InlineAsm::AsmDialect asmDialect) const override;
 };
 
 class X86MCAsmInfoMicrosoftMASM : public X86MCAsmInfoMicrosoft {
@@ -60,6 +63,7 @@
 
 public:
   explicit X86MCAsmInfoGNUCOFF(const Triple &Triple);
+  unsigned getInlineAsmDialect(InlineAsm::AsmDialect asmDialect) const override;
 };
 } // namespace llvm
 
Index: llvm/lib/Target/X86/MCTargetDesc/X86MCAsmInfo.cpp
===================================================================
--- llvm/lib/Target/X86/MCTargetDesc/X86MCAsmInfo.cpp
+++ llvm/lib/Target/X86/MCTargetDesc/X86MCAsmInfo.cpp
@@ -18,11 +18,17 @@
 using namespace llvm;
 
 enum AsmWriterFlavorTy {
-  // Note: This numbering has to match the GCC assembler dialects for inline
-  // asm alternatives to work right.
   ATT = 0, Intel = 1
 };
 
+static enum AsmWriterFlavorTy X86InlineAsmDialect(InlineAsm::AsmDialect asmDialect) {
+  switch (asmDialect) {
+    case InlineAsm::AD_ATT: return ATT;
+    case InlineAsm::AD_Intel: return Intel;
+  }
+  llvm_unreachable("Invalid inline assembler dialect");
+}
+
 static cl::opt<AsmWriterFlavorTy> AsmWriterFlavor(
     "x86-asm-syntax", cl::init(ATT), cl::Hidden,
     cl::desc("Choose style of code to emit from X86 backend:"),
@@ -73,6 +79,10 @@
   DwarfFDESymbolsUseAbsDiff = true;
 }
 
+unsigned X86MCAsmInfoDarwin::getInlineAsmDialect(InlineAsm::AsmDialect asmDialect) const {
+  return X86InlineAsmDialect(asmDialect);
+}
+
 X86_64MCAsmInfoDarwin::X86_64MCAsmInfoDarwin(const Triple &Triple)
   : X86MCAsmInfoDarwin(Triple) {
 }
@@ -102,6 +112,10 @@
   ExceptionsType = ExceptionHandling::DwarfCFI;
 }
 
+unsigned X86ELFMCAsmInfo::getInlineAsmDialect(InlineAsm::AsmDialect asmDialect) const {
+  return X86InlineAsmDialect(asmDialect);
+}
+
 const MCExpr *
 X86_64MCAsmInfoDarwin::getExprForPersonalitySymbol(const MCSymbol *Sym,
                                                    unsigned Encoding,
@@ -137,6 +151,10 @@
   AllowAtInName = true;
 }
 
+unsigned X86MCAsmInfoMicrosoft::getInlineAsmDialect(InlineAsm::AsmDialect asmDialect) const {
+  return X86InlineAsmDialect(asmDialect);
+}
+
 void X86MCAsmInfoMicrosoftMASM::anchor() { }
 
 X86MCAsmInfoMicrosoftMASM::X86MCAsmInfoMicrosoftMASM(const Triple &Triple)
@@ -167,3 +185,7 @@
 
   AllowAtInName = true;
 }
+
+unsigned X86MCAsmInfoGNUCOFF::getInlineAsmDialect(InlineAsm::AsmDialect asmDialect) const {
+  return X86InlineAsmDialect(asmDialect);
+}