Index: lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp
===================================================================
--- lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp
+++ lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp
@@ -134,6 +134,7 @@
     }
     break;
   case Mips::fixup_MIPS_PC18_S3:
+  case Mips::fixup_MICROMIPS_PC18_S3:
     // Forcing a signed division because Value can be negative.
     Value = (int64_t)Value / 8;
     // We now check if Value can be encoded as a 18-bit signed immediate.
@@ -316,6 +317,7 @@
     { "fixup_MICROMIPS_PC7_S1",  0,      7,   MCFixupKindInfo::FKF_IsPCRel },
     { "fixup_MICROMIPS_PC10_S1", 0,     10,   MCFixupKindInfo::FKF_IsPCRel },
     { "fixup_MICROMIPS_PC16_S1", 0,     16,   MCFixupKindInfo::FKF_IsPCRel },
+    { "fixup_MICROMIPS_PC18_S3", 0,     18,   MCFixupKindInfo::FKF_IsPCRel },
     { "fixup_MICROMIPS_CALL16",  0,     16,   0 },
     { "fixup_MICROMIPS_GOT_DISP",        0,     16,   0 },
     { "fixup_MICROMIPS_GOT_PAGE",        0,     16,   0 },
@@ -382,6 +384,7 @@
     { "fixup_MICROMIPS_PC7_S1",  9,      7,   MCFixupKindInfo::FKF_IsPCRel },
     { "fixup_MICROMIPS_PC10_S1", 6,     10,   MCFixupKindInfo::FKF_IsPCRel },
     { "fixup_MICROMIPS_PC16_S1",16,     16,   MCFixupKindInfo::FKF_IsPCRel },
+    { "fixup_MICROMIPS_PC18_S3",14,     18,   MCFixupKindInfo::FKF_IsPCRel },
     { "fixup_MICROMIPS_CALL16", 16,     16,   0 },
     { "fixup_MICROMIPS_GOT_DISP",        16,     16,   0 },
     { "fixup_MICROMIPS_GOT_PAGE",        16,     16,   0 },
Index: lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp
===================================================================
--- lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp
+++ lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp
@@ -89,6 +89,8 @@
       return ELF::R_MICROMIPS_PC10_S1;
     case Mips::fixup_MICROMIPS_PC16_S1:
       return ELF::R_MICROMIPS_PC16_S1;
+    case Mips::fixup_MICROMIPS_PC18_S3:
+      return ELF::R_MICROMIPS_PC18_S3;
     case Mips::fixup_MIPS_PC19_S2:
       return ELF::R_MIPS_PC19_S2;
     case Mips::fixup_MIPS_PC18_S3:
Index: lib/Target/Mips/MCTargetDesc/MipsFixupKinds.h
===================================================================
--- lib/Target/Mips/MCTargetDesc/MipsFixupKinds.h
+++ lib/Target/Mips/MCTargetDesc/MipsFixupKinds.h
@@ -170,6 +170,9 @@
     // resulting in - R_MICROMIPS_PC16_S1
     fixup_MICROMIPS_PC16_S1,
 
+    // resulting in - R_MICROMIPS_PC18_S3
+    fixup_MICROMIPS_PC18_S3,
+
     // resulting in - R_MICROMIPS_CALL16
     fixup_MICROMIPS_CALL16,
 
Index: lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
===================================================================
--- lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
+++ lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
@@ -919,8 +919,9 @@
          "getSimm18Lsl2Encoding expects only expressions or an immediate");
 
   const MCExpr *Expr = MO.getExpr();
-  Fixups.push_back(MCFixup::create(0, Expr,
-                                   MCFixupKind(Mips::fixup_MIPS_PC18_S3)));
+  Mips::Fixups FixupKind = isMicroMips(STI) ? Mips::fixup_MICROMIPS_PC18_S3
+                                            : Mips::fixup_MIPS_PC18_S3;
+  Fixups.push_back(MCFixup::create(0, Expr, MCFixupKind(FixupKind)));
   return 0;
 }
 
Index: test/MC/Mips/micromips64r6/relocations.s
===================================================================
--- /dev/null
+++ test/MC/Mips/micromips64r6/relocations.s
@@ -0,0 +1,18 @@
+# RUN: llvm-mc %s -triple=mips-unknown-linux -show-encoding -mcpu=mips64r6 \
+# RUN:   -mattr=micromips | FileCheck %s -check-prefix=CHECK-FIXUP
+# RUN: llvm-mc %s -filetype=obj -triple=mips-unknown-linux -mcpu=mips64r6 \
+# RUN:   -mattr=micromips | llvm-readobj -r | FileCheck %s -check-prefix=CHECK-ELF
+#------------------------------------------------------------------------------
+# Check that the assembler can handle the documented syntax for fixups.
+#------------------------------------------------------------------------------
+# CHECK-FIXUP: ldpc  $2, bar    # encoding: [0x78,0b010110AA,A,A]
+# CHECK-FIXUP:                  #   fixup A - offset: 0,
+# CHECK-FIXUP:                      value: bar, kind: fixup_MICROMIPS_PC18_S3
+#------------------------------------------------------------------------------
+# Check that the appropriate relocations were created.
+#------------------------------------------------------------------------------
+# CHECK-ELF: Relocations [
+# CHECK-ELF:     0x0 R_MICROMIPS_PC18_S3 bar 0x0
+# CHECK-ELF: ]
+
+  ldpc  $2, bar