Index: lib/Target/Mips/AsmParser/MipsAsmParser.cpp
===================================================================
--- lib/Target/Mips/AsmParser/MipsAsmParser.cpp
+++ lib/Target/Mips/AsmParser/MipsAsmParser.cpp
@@ -177,6 +177,7 @@
   const MCExpr *evaluateRelocExpr(const MCExpr *Expr, StringRef RelocStr);
 
   bool isEvaluated(const MCExpr *Expr);
+  bool parseSetMips0Directive();
   bool parseSetArchDirective();
   bool parseSetFeature(uint64_t Feature);
   bool parseDirectiveCPLoad(SMLoc Loc);
@@ -2731,6 +2732,19 @@
   return false;
 }
 
+bool MipsAsmParser::parseSetMips0Directive() {
+  Parser.Lex();
+  if (getLexer().isNot(AsmToken::EndOfStatement))
+    return reportParseError("unexpected token, expected end of statement");
+
+  // Reset assembler options to their initial values.
+  setAvailableFeatures(AssemblerOptions.front()->getFeatures());
+  AssemblerOptions.back()->setFeatures(AssemblerOptions.front()->getFeatures());
+
+  getTargetStreamer().emitDirectiveSetMips0();
+  return false;
+}
+
 bool MipsAsmParser::parseSetArchDirective() {
   Parser.Lex();
   if (getLexer().isNot(AsmToken::Equal))
@@ -2981,6 +2995,8 @@
     return false;
   } else if (Tok.getString() == "micromips") {
     return parseSetFeature(Mips::FeatureMicroMips);
+  } else if (Tok.getString() == "mips0") {
+    return parseSetMips0Directive();
   } else if (Tok.getString() == "mips1") {
     return parseSetFeature(Mips::FeatureMips1);
   } else if (Tok.getString() == "mips2") {
Index: lib/Target/Mips/MCTargetDesc/MipsTargetStreamer.cpp
===================================================================
--- lib/Target/Mips/MCTargetDesc/MipsTargetStreamer.cpp
+++ lib/Target/Mips/MCTargetDesc/MipsTargetStreamer.cpp
@@ -59,6 +59,7 @@
 void MipsTargetStreamer::emitDirectiveSetArch(StringRef Arch) {
   forbidModuleDirective();
 }
+void MipsTargetStreamer::emitDirectiveSetMips0() {}
 void MipsTargetStreamer::emitDirectiveSetMips1() { forbidModuleDirective(); }
 void MipsTargetStreamer::emitDirectiveSetMips2() { forbidModuleDirective(); }
 void MipsTargetStreamer::emitDirectiveSetMips3() { forbidModuleDirective(); }
@@ -184,6 +185,8 @@
   MipsTargetStreamer::emitDirectiveSetArch(Arch);
 }
 
+void MipsTargetAsmStreamer::emitDirectiveSetMips0() { OS << "\t.set\tmips0\n"; }
+
 void MipsTargetAsmStreamer::emitDirectiveSetMips1() {
   OS << "\t.set\tmips1\n";
   MipsTargetStreamer::emitDirectiveSetMips1();
Index: lib/Target/Mips/MipsTargetStreamer.h
===================================================================
--- lib/Target/Mips/MipsTargetStreamer.h
+++ lib/Target/Mips/MipsTargetStreamer.h
@@ -49,6 +49,7 @@
   virtual void emitFMask(unsigned FPUBitmask, int FPUTopSavedRegOff);
 
   virtual void emitDirectiveSetArch(StringRef Arch);
+  virtual void emitDirectiveSetMips0();
   virtual void emitDirectiveSetMips1();
   virtual void emitDirectiveSetMips2();
   virtual void emitDirectiveSetMips3();
@@ -151,6 +152,7 @@
   void emitFMask(unsigned FPUBitmask, int FPUTopSavedRegOff) override;
 
   void emitDirectiveSetArch(StringRef Arch) override;
+  void emitDirectiveSetMips0() override;
   void emitDirectiveSetMips1() override;
   void emitDirectiveSetMips2() override;
   void emitDirectiveSetMips3() override;
Index: test/MC/Mips/set-mips0-directive.s
===================================================================
--- /dev/null
+++ test/MC/Mips/set-mips0-directive.s
@@ -0,0 +1,27 @@
+# RUN: llvm-mc %s -triple=mipsel-unknown-linux -mcpu=mips32r2 | \
+# RUN:   FileCheck %s
+
+    .text
+    rotr  $7, $7, 22
+
+    .set mips32r6
+    mod   $2, $4, $6
+    .set mips0
+    rotr  $2, $2, 15
+
+    .set mips3
+    dadd  $4, $4, $4
+    .set mips0
+    rotr  $3, $3, 19
+
+# CHECK: rotr  $7, $7, 22
+
+# CHECK: .set mips32r6
+# CHECK: mod   $2, $4, $6
+# CHECK: .set mips0
+# CHECK: rotr  $2, $2, 15
+
+# CHECK: .set mips3
+# CHECK: dadd  $4, $4, $4
+# CHECK: .set mips0
+# CHECK: rotr  $3, $3, 19