Index: lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
===================================================================
--- lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -419,7 +419,7 @@
   addUInt(*ScopeDIE, dwarf::DW_AT_call_file, None,
           getOrCreateSourceID(IA->getFilename(), IA->getDirectory()));
   addUInt(*ScopeDIE, dwarf::DW_AT_call_line, None, IA->getLine());
-  if (IA->getDiscriminator())
+  if (IA->getDiscriminator() && DD->getDwarfVersion() >= 4)
     addUInt(*ScopeDIE, dwarf::DW_AT_GNU_discriminator, None,
             IA->getDiscriminator());
 
Index: lib/CodeGen/AsmPrinter/DwarfDebug.cpp
===================================================================
--- lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -1190,7 +1190,8 @@
     Fn = Scope->getFilename();
     Dir = Scope->getDirectory();
     if (auto *LBF = dyn_cast<DILexicalBlockFile>(Scope))
-      Discriminator = LBF->getDiscriminator();
+      if (DwarfVersion >= 4)
+        Discriminator = LBF->getDiscriminator();
 
     unsigned CUID = Asm->OutStreamer->getContext().getDwarfCompileUnitID();
     Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
Index: lib/MC/MCDwarf.cpp
===================================================================
--- lib/MC/MCDwarf.cpp
+++ lib/MC/MCDwarf.cpp
@@ -122,7 +122,8 @@
       MCOS->EmitIntValue(dwarf::DW_LNS_set_column, 1);
       MCOS->EmitULEB128IntValue(Column);
     }
-    if (Discriminator != LineEntry.getDiscriminator()) {
+    if (Discriminator != LineEntry.getDiscriminator() &&
+        MCOS->getContext().getDwarfVersion() >= 4) {
       Discriminator = LineEntry.getDiscriminator();
       unsigned Size = getULEB128Size(Discriminator);
       MCOS->EmitIntValue(dwarf::DW_LNS_extended_op, 1);
Index: lib/Transforms/Utils/AddDiscriminators.cpp
===================================================================
--- lib/Transforms/Utils/AddDiscriminators.cpp
+++ lib/Transforms/Utils/AddDiscriminators.cpp
@@ -159,10 +159,7 @@
   // If the function has debug information, but the user has disabled
   // discriminators, do nothing.
   // Simlarly, if the function has no debug info, do nothing.
-  // Finally, if this module is built with dwarf versions earlier than 4,
-  // do nothing (discriminator support is a DWARF 4 feature).
-  if (NoDiscriminators || !F.getSubprogram() ||
-      F.getParent()->getDwarfVersion() < 4)
+  if (NoDiscriminators || !F.getSubprogram())
     return false;
 
   bool Changed = false;