Index: lib/Basic/Targets.cpp
===================================================================
--- lib/Basic/Targets.cpp
+++ lib/Basic/Targets.cpp
@@ -3252,18 +3252,27 @@
 class X86_64TargetInfo : public X86TargetInfo {
 public:
   X86_64TargetInfo(const llvm::Triple &Triple) : X86TargetInfo(Triple) {
-    LongWidth = LongAlign = PointerWidth = PointerAlign = 64;
+    const bool IsX32{getTriple().getEnvironment() == llvm::Triple::GNUX32};
+    LongWidth = LongAlign = PointerWidth = PointerAlign = IsX32 ? 32 : 64;
     LongDoubleWidth = 128;
     LongDoubleAlign = 128;
     LargeArrayMinWidth = 128;
     LargeArrayAlign = 128;
     SuitableAlign = 128;
-    IntMaxType = SignedLong;
-    UIntMaxType = UnsignedLong;
-    Int64Type = SignedLong;
+    if (IsX32) {
+      SizeType = UnsignedInt;
+      PtrDiffType = SignedInt;
+      IntPtrType = SignedInt;
+    } else {
+      IntMaxType = SignedLong;
+      UIntMaxType = UnsignedLong;
+      Int64Type = SignedLong;
+    }
     RegParmMax = 6;
 
-    DescriptionString = "e-m:e-i64:64-f80:128-n8:16:32:64-S128";
+    DescriptionString = (IsX32)
+                            ? "e-m:e-p:32:32-i64:64-f80:128-n8:16:32:64-S128"
+                            : "e-m:e-i64:64-f80:128-n8:16:32:64-S128";
 
     // Use fpret only for long double.
     RealTypeUsesObjCFPRet = (1 << TargetInfo::LongDouble);
Index: lib/Driver/ToolChains.cpp
===================================================================
--- lib/Driver/ToolChains.cpp
+++ lib/Driver/ToolChains.cpp
@@ -1943,6 +1943,26 @@
 
   FilterNonExistent NonExistent(Path);
 
+  // For x32 case enforce single lib support for now.
+  // In fact there can be 3 libs support like in GCC controlled by
+  // flags -m32/-m64/-mx32.
+  if (TargetTriple.getEnvironment() == llvm::Triple::GNUX32) {
+    Multilib Altx32 = Multilib()
+                          .gccSuffix("/x32")
+                          .includeSuffix("/x32")
+                          .flag("+mx32")
+                          .flag("-m64")
+                          .flag("-m32");
+
+    Result.Multilibs.push_back(Altx32);
+    Result.Multilibs.FilterOut(NonExistent);
+
+    Multilib::flags_list Flags;
+    addMultilibFlag(true, "mx32", Flags);
+    Result.BiarchSibling = Alt64;
+
+    return Result.Multilibs.select(Flags, Result.SelectedMultilib);
+  }
   // Decide whether the default multilib is 32bit, correcting for
   // when the default multilib and the alternate appear backwards
   bool DefaultIs32Bit;
@@ -2889,7 +2909,8 @@
       return "i386-linux-gnu";
     return TargetTriple.str();
   case llvm::Triple::x86_64:
-    if (llvm::sys::fs::exists(SysRoot + "/lib/x86_64-linux-gnu"))
+    if (llvm::sys::fs::exists(SysRoot + "/lib/x86_64-linux-gnu") &&
+        TargetTriple.getEnvironment() != llvm::Triple::GNUX32)
       return "x86_64-linux-gnu";
     return TargetTriple.str();
   case llvm::Triple::arm64:
@@ -2953,6 +2974,9 @@
       Triple.getArch() == llvm::Triple::ppc)
     return "lib32";
 
+  if (Triple.getEnvironment() == llvm::Triple::GNUX32)
+    return "libx32";
+
   return Triple.isArch32Bit() ? "lib" : "lib64";
 }
 
Index: lib/Driver/Tools.cpp
===================================================================
--- lib/Driver/Tools.cpp
+++ lib/Driver/Tools.cpp
@@ -6727,6 +6727,9 @@
     CmdArgs.push_back("--32");
   } else if (getToolChain().getArch() == llvm::Triple::x86_64) {
     CmdArgs.push_back("--64");
+  } else if (getToolChain().getTriple().getEnvironment() ==
+             llvm::Triple::GNUX32) {
+    CmdArgs.push_back("--x32");
   } else if (getToolChain().getArch() == llvm::Triple::ppc) {
     CmdArgs.push_back("-a32");
     CmdArgs.push_back("-mppc");
@@ -6922,6 +6925,8 @@
     return "/lib64/ld64.so.1";
   else if (ToolChain.getArch() == llvm::Triple::sparcv9)
     return "/lib64/ld-linux.so.2";
+  else if (ToolChain.getTriple().getEnvironment() == llvm::Triple::GNUX32)
+    return "/libx32/ld-linux-x32.so.2";
   else
     return "/lib64/ld-linux-x86-64.so.2";
 }
@@ -7032,6 +7037,8 @@
   }
   else if (ToolChain.getArch() == llvm::Triple::systemz)
     CmdArgs.push_back("elf64_s390");
+  else if (ToolChain.getTriple().getEnvironment() == llvm::Triple::GNUX32)
+    CmdArgs.push_back("elf32_x86_64");
   else
     CmdArgs.push_back("elf_x86_64");