diff --git a/clang/lib/Driver/ToolChains/Gnu.cpp b/clang/lib/Driver/ToolChains/Gnu.cpp
--- a/clang/lib/Driver/ToolChains/Gnu.cpp
+++ b/clang/lib/Driver/ToolChains/Gnu.cpp
@@ -2086,7 +2086,10 @@
       "x86_64-manbo-linux-gnu", "x86_64-linux-gnu",
       "x86_64-slackware-linux", "x86_64-unknown-linux",
       "x86_64-amazon-linux",    "x86_64-linux-android"};
-  static const char *const X32LibDirs[] = {"/libx32"};
+  static const char *const X32LibDirs[] = {"/libx32", "/lib"};
+  static const char *const X32Triples[] = {
+      "x86_64-linux-gnux32",    "x86_64-unknown-linux-gnux32",
+      "x86_64-pc-linux-gnux32"};
   static const char *const X86LibDirs[] = {"/lib32", "/lib"};
   static const char *const X86Triples[] = {
       "i686-linux-gnu",       "i686-pc-linux-gnu",     "i486-linux-gnu",
@@ -2307,14 +2310,16 @@
     TripleAliases.append(begin(AVRTriples), end(AVRTriples));
     break;
   case llvm::Triple::x86_64:
-    LibDirs.append(begin(X86_64LibDirs), end(X86_64LibDirs));
-    TripleAliases.append(begin(X86_64Triples), end(X86_64Triples));
     // x32 is always available when x86_64 is available, so adding it as
     // secondary arch with x86_64 triples
     if (TargetTriple.getEnvironment() == llvm::Triple::GNUX32) {
-      BiarchLibDirs.append(begin(X32LibDirs), end(X32LibDirs));
+      LibDirs.append(begin(X32LibDirs), end(X32LibDirs));
+      TripleAliases.append(begin(X32Triples), end(X32Triples));
+      BiarchLibDirs.append(begin(X86_64LibDirs), end(X86_64LibDirs));
       BiarchTripleAliases.append(begin(X86_64Triples), end(X86_64Triples));
     } else {
+      LibDirs.append(begin(X86_64LibDirs), end(X86_64LibDirs));
+      TripleAliases.append(begin(X86_64Triples), end(X86_64Triples));
       BiarchLibDirs.append(begin(X86LibDirs), end(X86LibDirs));
       BiarchTripleAliases.append(begin(X86Triples), end(X86Triples));
     }
diff --git a/clang/lib/Driver/ToolChains/Linux.cpp b/clang/lib/Driver/ToolChains/Linux.cpp
--- a/clang/lib/Driver/ToolChains/Linux.cpp
+++ b/clang/lib/Driver/ToolChains/Linux.cpp
@@ -87,10 +87,13 @@
   case llvm::Triple::x86_64:
     if (IsAndroid)
       return "x86_64-linux-android";
-    // We don't want this for x32, otherwise it will match x86_64 libs
-    if (TargetEnvironment != llvm::Triple::GNUX32 &&
-        D.getVFS().exists(SysRoot + "/lib/x86_64-linux-gnu"))
-      return "x86_64-linux-gnu";
+    if (TargetEnvironment == llvm::Triple::GNUX32) {
+      if (D.getVFS().exists(SysRoot + "/lib/x86_64-linux-gnux32"))
+        return "x86_64-linux-gnux32";
+    } else {
+      if (D.getVFS().exists(SysRoot + "/lib/x86_64-linux-gnu"))
+        return "x86_64-linux-gnu";
+    }
     break;
   case llvm::Triple::aarch64:
     if (IsAndroid)
@@ -599,6 +602,8 @@
       // in use in any released version of Debian, so we should consider
       // removing them.
       "/usr/include/i686-linux-gnu/64", "/usr/include/i486-linux-gnu/64"};
+  const StringRef X32MultiarchIncludeDirs[] = {
+      "/usr/include/x86_64-linux-gnux32"};
   const StringRef X86MultiarchIncludeDirs[] = {
       "/usr/include/i386-linux-gnu",
 
@@ -656,7 +661,10 @@
   ArrayRef<StringRef> MultiarchIncludeDirs;
   switch (getTriple().getArch()) {
   case llvm::Triple::x86_64:
-    MultiarchIncludeDirs = X86_64MultiarchIncludeDirs;
+    if (getTriple().getEnvironment() == llvm::Triple::GNUX32)
+      MultiarchIncludeDirs = X32MultiarchIncludeDirs;
+    else
+      MultiarchIncludeDirs = X86_64MultiarchIncludeDirs;
     break;
   case llvm::Triple::x86:
     MultiarchIncludeDirs = X86MultiarchIncludeDirs;
diff --git a/clang/test/Driver/Inputs/debian_multiarch_tree/lib/x86_64-linux-gnux32/.keep b/clang/test/Driver/Inputs/debian_multiarch_tree/lib/x86_64-linux-gnux32/.keep
new file mode 100644
diff --git a/clang/test/Driver/Inputs/debian_multiarch_tree/usr/include/c++/4.5/x86_64-linux-gnux32/.keep b/clang/test/Driver/Inputs/debian_multiarch_tree/usr/include/c++/4.5/x86_64-linux-gnux32/.keep
new file mode 100644
diff --git a/clang/test/Driver/Inputs/debian_multiarch_tree/usr/include/x86_64-linux-gnux32/.keep b/clang/test/Driver/Inputs/debian_multiarch_tree/usr/include/x86_64-linux-gnux32/.keep
new file mode 100644
diff --git a/clang/test/Driver/Inputs/debian_multiarch_tree/usr/lib/gcc/x86_64-linux-gnux32/4.5/crtbegin.o b/clang/test/Driver/Inputs/debian_multiarch_tree/usr/lib/gcc/x86_64-linux-gnux32/4.5/crtbegin.o
new file mode 100644
diff --git a/clang/test/Driver/Inputs/debian_multiarch_tree/usr/lib/x86_64-linux-gnux32/.keep b/clang/test/Driver/Inputs/debian_multiarch_tree/usr/lib/x86_64-linux-gnux32/.keep
new file mode 100644
diff --git a/clang/test/Driver/linux-header-search.cpp b/clang/test/Driver/linux-header-search.cpp
--- a/clang/test/Driver/linux-header-search.cpp
+++ b/clang/test/Driver/linux-header-search.cpp
@@ -224,7 +224,23 @@
 // CHECK-DEBIAN-X86-64: "-internal-isystem" "[[RESOURCE_DIR]]{{/|\\\\}}include"
 // CHECK-DEBIAN-X86-64: "-internal-externc-isystem" "[[SYSROOT]]/usr/include/x86_64-linux-gnu"
 // CHECK-DEBIAN-X86-64: "-internal-externc-isystem" "[[SYSROOT]]/include"
-// CHECK-DEBIAN-X86-64: "-internal-externc-isystem" "[[SYSROOT]]/usr/include"
+// CHECK-DEBIAN-X86-64: "-internal-externc-isystem" "[[SYSROOT]]/usr/include
+// RUN: %clang -no-canonical-prefixes %s -### -fsyntax-only 2>&1 \
+// RUN:     -target x86_64-linux-gnux32 -stdlib=libstdc++ \
+// RUN:     --sysroot=%S/Inputs/debian_multiarch_tree \
+// RUN:     --gcc-toolchain="" \
+// RUN:   | FileCheck --check-prefix=CHECK-DEBIAN-X32 %s
+// CHECK-DEBIAN-X32: "{{[^"]*}}clang{{[^"]*}}" "-cc1"
+// CHECK-DEBIAN-X32: "-resource-dir" "[[RESOURCE_DIR:[^"]+]]"
+// CHECK-DEBIAN-X32: "-isysroot" "[[SYSROOT:[^"]+]]"
+// CHECK-DEBIAN-X32: "-internal-isystem" "[[SYSROOT]]/usr/lib/gcc/x86_64-linux-gnux32/4.5/../../../../include/c++/4.5"
+// CHECK-DEBIAN-X32: "-internal-isystem" "[[SYSROOT]]/usr/lib/gcc/x86_64-linux-gnux32/4.5/../../../../include/c++/4.5/x86_64-linux-gnux32"
+// CHECK-DEBIAN-X32: "-internal-isystem" "[[SYSROOT]]/usr/lib/gcc/x86_64-linux-gnux32/4.5/../../../../include/c++/4.5/backward"
+// CHECK-DEBIAN-X32: "-internal-isystem" "[[SYSROOT]]/usr/local/include"
+// CHECK-DEBIAN-X32: "-internal-isystem" "[[RESOURCE_DIR]]{{/|\\\\}}include"
+// CHECK-DEBIAN-X32: "-internal-externc-isystem" "[[SYSROOT]]/usr/include/x86_64-linux-gnux32"
+// CHECK-DEBIAN-X32: "-internal-externc-isystem" "[[SYSROOT]]/include"
+// CHECK-DEBIAN-X32: "-internal-externc-isystem" "[[SYSROOT]]/usr/include"
 // RUN: %clang -no-canonical-prefixes %s -### -fsyntax-only 2>&1 \
 // RUN:     -target powerpc-linux-gnu -stdlib=libstdc++ \
 // RUN:     --sysroot=%S/Inputs/debian_multiarch_tree \
diff --git a/clang/test/Driver/linux-ld.c b/clang/test/Driver/linux-ld.c
--- a/clang/test/Driver/linux-ld.c
+++ b/clang/test/Driver/linux-ld.c
@@ -1170,6 +1170,19 @@
 // CHECK-DEBIAN-X86-64: "-L[[SYSROOT]]/lib"
 // CHECK-DEBIAN-X86-64: "-L[[SYSROOT]]/usr/lib"
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:     --target=x86_64-linux-gnux32 -rtlib=platform \
+// RUN:     --gcc-toolchain="" \
+// RUN:     --sysroot=%S/Inputs/debian_multiarch_tree \
+// RUN:   | FileCheck --check-prefix=CHECK-DEBIAN-X32 %s
+// CHECK-DEBIAN-X32: "{{.*}}ld{{(.exe)?}}" "--sysroot=[[SYSROOT:[^"]+]]"
+// CHECK-DEBIAN-X32: "{{.*}}/usr/lib/gcc/x86_64-linux-gnux32/4.5{{/|\\\\}}crtbegin.o"
+// CHECK-DEBIAN-X32: "-L[[SYSROOT]]/usr/lib/gcc/x86_64-linux-gnux32/4.5"
+// CHECK-DEBIAN-X32: "-L[[SYSROOT]]/usr/lib/gcc/x86_64-linux-gnux32/4.5/../../../x86_64-linux-gnux32"
+// CHECK-DEBIAN-X32: "-L[[SYSROOT]]/usr/lib/x86_64-linux-gnux32"
+// CHECK-DEBIAN-X32: "-L[[SYSROOT]]/usr/lib/gcc/x86_64-linux-gnux32/4.5/../../.."
+// CHECK-DEBIAN-X32: "-L[[SYSROOT]]/lib"
+// CHECK-DEBIAN-X32: "-L[[SYSROOT]]/usr/lib"
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
 // RUN:     --target=powerpc-linux-gnu -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/debian_multiarch_tree \