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
@@ -2106,7 +2106,10 @@
       "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 X32Triples[] = {
+      "x86_64-linux-gnux32",    "x86_64-unknown-linux-gnux32",
+      "x86_64-pc-linux-gnux32"};
+  static const char *const X32LibDirs[] = {"/libx32", "/lib"};
   static const char *const X86LibDirs[] = {"/lib32", "/lib"};
   static const char *const X86Triples[] = {
       "i586-linux-gnu",     "i686-linux-gnu",
@@ -2337,17 +2340,19 @@
     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 {
-      BiarchLibDirs.append(begin(X86LibDirs), end(X86LibDirs));
-      BiarchTripleAliases.append(begin(X86Triples), end(X86Triples));
+      LibDirs.append(begin(X86_64LibDirs), end(X86_64LibDirs));
+      TripleAliases.append(begin(X86_64Triples), end(X86_64Triples));
+      BiarchLibDirs.append(begin(X32LibDirs), end(X32LibDirs));
+      BiarchTripleAliases.append(begin(X32Triples), end(X32Triples));
     }
+    BiarchLibDirs.append(begin(X86LibDirs), end(X86LibDirs));
+    BiarchTripleAliases.append(begin(X86Triples), end(X86Triples));
     break;
   case llvm::Triple::x86:
     LibDirs.append(begin(X86LibDirs), end(X86LibDirs));
@@ -2357,6 +2362,8 @@
       TripleAliases.append(begin(X86Triples), end(X86Triples));
       BiarchLibDirs.append(begin(X86_64LibDirs), end(X86_64LibDirs));
       BiarchTripleAliases.append(begin(X86_64Triples), end(X86_64Triples));
+      BiarchLibDirs.append(begin(X32LibDirs), end(X32LibDirs));
+      BiarchTripleAliases.append(begin(X32Triples), end(X32Triples));
     }
     break;
   case llvm::Triple::m68k:
diff --git a/clang/test/Driver/Inputs/basic_cross_linux_tree/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.0/x32/crtbegin.o b/clang/test/Driver/Inputs/basic_cross_linux_tree/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.0/x32/crtbegin.o
new file mode 100644
diff --git a/clang/test/Driver/Inputs/basic_cross_linux_tree/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.0/x32/crtbeginT.o b/clang/test/Driver/Inputs/basic_cross_linux_tree/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.0/x32/crtbeginT.o
new file mode 100644
diff --git a/clang/test/Driver/Inputs/basic_cross_linux_tree/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.0/x32/crtfastmath.o b/clang/test/Driver/Inputs/basic_cross_linux_tree/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.0/x32/crtfastmath.o
new file mode 100644
diff --git a/clang/test/Driver/baremetal.cpp b/clang/test/Driver/baremetal.cpp
--- a/clang/test/Driver/baremetal.cpp
+++ b/clang/test/Driver/baremetal.cpp
@@ -34,7 +34,7 @@
 // RUN:     --sysroot=%S/Inputs/baremetal_arm \
 // RUN:   | FileCheck --check-prefix=CHECK-V6M-DEFAULTCXX %s
 // CHECK-V6M-DEFAULTCXX: "{{[^"]*}}ld{{(\.(lld|bfd|gold))?}}{{(\.exe)?}}" "{{.*}}.o" "-Bstatic"
-// CHECK-V6M-DEFAULTCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}lib{{(64)?}}{{[/\\]+}}clang{{[/\\]+}}{{.*}}{{[/\\]+}}lib{{[/\\]+}}baremetal"
+// CHECK-V6M-DEFAULTCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}lib{{(64|x32)?}}{{[/\\]+}}clang{{[/\\]+}}{{.*}}{{[/\\]+}}lib{{[/\\]+}}baremetal"
 // CHECK-V6M-DEFAULTCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}Inputs{{[/\\]+}}baremetal_arm{{[/\\]+}}lib"
 // CHECK-V6M-DEFAULTCXX-SAME: "-lc++" "-lc++abi" "-lunwind"
 // CHECK-V6M-DEFAULTCXX-SAME: "-lc" "-lm" "-lclang_rt.builtins-armv6m"
@@ -48,7 +48,7 @@
 // CHECK-V6M-LIBCXX-NOT: "-internal-isystem" "{{[^"]+}}{{[/\\]+}}include{{[/\\]+}}c++{{[/\\]+}}{{[^v].*}}"
 // CHECK-V6M-LIBCXX: "-internal-isystem" "{{[^"]+}}{{[/\\]+}}include{{[/\\]+}}c++{{[/\\]+}}v1"
 // CHECK-V6M-LIBCXX: "{{[^"]*}}ld{{(\.(lld|bfd|gold))?}}{{(\.exe)?}}" "{{.*}}.o" "-Bstatic"
-// CHECK-V6M-LIBCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}lib{{(64)?}}{{[/\\]+}}clang{{[/\\]+}}{{.*}}{{[/\\]+}}lib{{[/\\]+}}baremetal"
+// CHECK-V6M-LIBCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}lib{{(64|x32)?}}{{[/\\]+}}clang{{[/\\]+}}{{.*}}{{[/\\]+}}lib{{[/\\]+}}baremetal"
 // CHECK-V6M-LIBCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}Inputs{{[/\\]+}}baremetal_arm{{[/\\]+}}lib"
 // CHECK-V6M-LIBCXX-SAME: "-lc++" "-lc++abi" "-lunwind"
 // CHECK-V6M-LIBCXX-SAME: "-lc" "-lm" "-lclang_rt.builtins-armv6m"
@@ -62,7 +62,7 @@
 // CHECK-V6M-LIBSTDCXX-NOT: "-internal-isystem" "{{[^"]+}}{{[/\\]+}}include{{[/\\]+}}c++{{[/\\]+}}v1"
 // CHECK-V6M-LIBSTDCXX: "-internal-isystem" "{{[^"]+}}{{[/\\]+}}include{{[/\\]+}}c++{{[/\\]+}}6.0.0"
 // CHECK-V6M-LIBSTDCXX: "{{[^"]*}}ld{{(\.(lld|bfd|gold))?}}{{(\.exe)?}}" "{{.*}}.o" "-Bstatic"
-// CHECK-V6M-LIBSTDCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}lib{{(64)?}}{{[/\\]+}}clang{{[/\\]+}}{{.*}}{{[/\\]+}}lib{{[/\\]+}}baremetal"
+// CHECK-V6M-LIBSTDCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}lib{{(64|x32)?}}{{[/\\]+}}clang{{[/\\]+}}{{.*}}{{[/\\]+}}lib{{[/\\]+}}baremetal"
 // CHECK-V6M-LIBSTDCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}Inputs{{[/\\]+}}baremetal_arm{{[/\\]+}}lib"
 // CHECK-V6M-LIBSTDCXX-SAME: "-lstdc++" "-lsupc++" "-lunwind"
 // CHECK-V6M-LIBSTDCXX-SAME: "-lc" "-lm" "-lclang_rt.builtins-armv6m"
@@ -74,7 +74,7 @@
 // RUN:     -nodefaultlibs \
 // RUN:   | FileCheck --check-prefix=CHECK-V6M-NDL %s
 // CHECK-V6M-NDL: "{{[^"]*}}ld{{(\.(lld|bfd|gold))?}}{{(\.exe)?}}" "{{.*}}.o" "-Bstatic"
-// CHECK-V6M-NDL-SAME: "-L{{[^"]*}}{{[/\\]+}}lib{{(64)?}}{{[/\\]+}}clang{{[/\\]+}}{{.*}}{{[/\\]+}}lib{{[/\\]+}}baremetal"
+// CHECK-V6M-NDL-SAME: "-L{{[^"]*}}{{[/\\]+}}lib{{(64|x32)?}}{{[/\\]+}}clang{{[/\\]+}}{{.*}}{{[/\\]+}}lib{{[/\\]+}}baremetal"
 // CHECK-V6M-NDL-SAME: "-L{{[^"]*}}{{[/\\]+}}Inputs{{[/\\]+}}baremetal_arm{{[/\\]+}}lib" "-o" "{{.*}}.o"
 
 // RUN: %clangxx -target arm-none-eabi -v 2>&1 \
@@ -120,7 +120,7 @@
 // RUN:     --sysroot=%S/Inputs/basic_riscv64_tree/riscv64-unknown-elf \
 // RUN:   | FileCheck --check-prefix=CHECK-RV64-DEFAULTCXX %s
 // CHECK-RV64-DEFAULTCXX: "{{[^"]*}}ld{{(\.(lld|bfd|gold))?}}{{(\.exe)?}}" "{{.*}}.o" "-Bstatic"
-// CHECK-RV64-DEFAULTCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}lib{{(64)?}}{{[/\\]+}}clang{{[/\\]+}}{{.*}}{{[/\\]+}}lib{{[/\\]+}}baremetal"
+// CHECK-RV64-DEFAULTCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}lib{{(64|x32)?}}{{[/\\]+}}clang{{[/\\]+}}{{.*}}{{[/\\]+}}lib{{[/\\]+}}baremetal"
 // CHECK-RV64-DEFAULTCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}Inputs{{[/\\]+}}basic_riscv64_tree{{[/\\]+}}riscv64-unknown-elf{{[/\\]+}}lib"
 // CHECK-RV64-DEFAULTCXX-SAME: "-lc++" "-lc++abi" "-lunwind"
 // CHECK-RV64-DEFAULTCXX-SAME: "-lc" "-lm" "-lclang_rt.builtins-riscv64"
@@ -134,7 +134,7 @@
 // CHECK-RV64-LIBCXX-NOT: "-internal-isystem" "{{[^"]+}}{{[/\\]+}}include{{[/\\]+}}c++{{[/\\]+}}{{[^v].*}}"
 // CHECK-RV64-LIBCXX: "-internal-isystem" "{{[^"]+}}{{[/\\]+}}include{{[/\\]+}}c++{{[/\\]+}}v1"
 // CHECK-RV64-LIBCXX: "{{[^"]*}}ld{{(\.(lld|bfd|gold))?}}{{(\.exe)?}}" "{{.*}}.o" "-Bstatic"
-// CHECK-RV64-LIBCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}lib{{(64)?}}{{[/\\]+}}clang{{[/\\]+}}{{.*}}{{[/\\]+}}lib{{[/\\]+}}baremetal"
+// CHECK-RV64-LIBCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}lib{{(64|x32)?}}{{[/\\]+}}clang{{[/\\]+}}{{.*}}{{[/\\]+}}lib{{[/\\]+}}baremetal"
 // CHECK-RV64-LIBCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}Inputs{{[/\\]+}}basic_riscv64_tree{{[/\\]+}}riscv64-unknown-elf{{[/\\]+}}lib"
 // CHECK-RV64-LIBCXX-SAME: "-lc++" "-lc++abi" "-lunwind"
 // CHECK-RV64-LIBCXX-SAME: "-lc" "-lm" "-lclang_rt.builtins-riscv64"
@@ -148,7 +148,7 @@
 // CHECK-RV64-LIBSTDCXX-NOT: "-internal-isystem" "{{[^"]+}}{{[/\\]+}}include{{[/\\]+}}c++{{[/\\]+}}v1"
 // CHECK-RV64-LIBSTDCXX: "-internal-isystem" "{{[^"]+}}{{[/\\]+}}include{{[/\\]+}}c++{{[/\\]+}}8.0.1"
 // CHECK-RV64-LIBSTDCXX: "{{[^"]*}}ld{{(\.(lld|bfd|gold))?}}{{(\.exe)?}}" "{{.*}}.o" "-Bstatic"
-// CHECK-RV64-LIBSTDCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}lib{{(64)?}}{{[/\\]+}}clang{{[/\\]+}}{{.*}}{{[/\\]+}}lib{{[/\\]+}}baremetal"
+// CHECK-RV64-LIBSTDCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}lib{{(64|x32)?}}{{[/\\]+}}clang{{[/\\]+}}{{.*}}{{[/\\]+}}lib{{[/\\]+}}baremetal"
 // CHECK-RV64-LIBSTDCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}Inputs{{[/\\]+}}basic_riscv64_tree{{[/\\]+}}riscv64-unknown-elf{{[/\\]+}}lib"
 // CHECK-RV64-LIBSTDCXX-SAME: "-lstdc++" "-lsupc++" "-lunwind"
 // CHECK-RV64-LIBSTDCXX-SAME: "-lc" "-lm" "-lclang_rt.builtins-riscv64"
@@ -177,7 +177,7 @@
 // RUN:     --sysroot=%S/Inputs/basic_riscv32_tree/riscv32-unknown-elf \
 // RUN:   | FileCheck --check-prefix=CHECK-RV32-DEFAULTCXX %s
 // CHECK-RV32-DEFAULTCXX: "{{[^"]*}}ld{{(\.(lld|bfd|gold))?}}{{(\.exe)?}}" "{{.*}}.o" "-Bstatic"
-// CHECK-RV32-DEFAULTCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}lib{{(64)?}}{{[/\\]+}}clang{{[/\\]+}}{{.*}}{{[/\\]+}}lib{{[/\\]+}}baremetal"
+// CHECK-RV32-DEFAULTCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}lib{{(64|x32)?}}{{[/\\]+}}clang{{[/\\]+}}{{.*}}{{[/\\]+}}lib{{[/\\]+}}baremetal"
 // CHECK-RV32-DEFAULTCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}Inputs{{[/\\]+}}basic_riscv32_tree{{[/\\]+}}riscv32-unknown-elf{{[/\\]+}}lib"
 // CHECK-RV32-DEFAULTCXX-SAME: "-lc++" "-lc++abi" "-lunwind"
 // CHECK-RV32-DEFAULTCXX-SAME: "-lc" "-lm" "-lclang_rt.builtins-riscv32"
@@ -191,7 +191,7 @@
 // CHECK-RV32-LIBCXX-NOT: "-internal-isystem" "{{[^"]+}}{{[/\\]+}}include{{[/\\]+}}c++{{[/\\]+}}{{[^v].*}}"
 // CHECK-RV32-LIBCXX: "-internal-isystem" "{{[^"]+}}{{[/\\]+}}include{{[/\\]+}}c++{{[/\\]+}}v1"
 // CHECK-RV32-LIBCXX: "{{[^"]*}}ld{{(\.(lld|bfd|gold))?}}{{(\.exe)?}}" "{{.*}}.o" "-Bstatic"
-// CHECK-RV32-LIBCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}lib{{(64)?}}{{[/\\]+}}clang{{[/\\]+}}{{.*}}{{[/\\]+}}lib{{[/\\]+}}baremetal"
+// CHECK-RV32-LIBCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}lib{{(64|x32)?}}{{[/\\]+}}clang{{[/\\]+}}{{.*}}{{[/\\]+}}lib{{[/\\]+}}baremetal"
 // CHECK-RV32-LIBCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}Inputs{{[/\\]+}}basic_riscv32_tree{{[/\\]+}}riscv32-unknown-elf{{[/\\]+}}lib"
 // CHECK-RV32-LIBCXX-SAME: "-lc++" "-lc++abi" "-lunwind"
 // CHECK-RV32-LIBCXX-SAME: "-lc" "-lm" "-lclang_rt.builtins-riscv32"
@@ -205,7 +205,7 @@
 // CHECK-RV32-LIBSTDCXX-NOT: "-internal-isystem" "{{[^"]+}}{{[/\\]+}}include{{[/\\]+}}c++{{[/\\]+}}v1"
 // CHECK-RV32-LIBSTDCXX: "-internal-isystem" "{{[^"]+}}{{[/\\]+}}include{{[/\\]+}}c++{{[/\\]+}}8.0.1"
 // CHECK-RV32-LIBSTDCXX: "{{[^"]*}}ld{{(\.(lld|bfd|gold))?}}{{(\.exe)?}}" "{{.*}}.o" "-Bstatic"
-// CHECK-RV32-LIBSTDCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}lib{{(64)?}}{{[/\\]+}}clang{{[/\\]+}}{{.*}}{{[/\\]+}}lib{{[/\\]+}}baremetal"
+// CHECK-RV32-LIBSTDCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}lib{{(64|x32)?}}{{[/\\]+}}clang{{[/\\]+}}{{.*}}{{[/\\]+}}lib{{[/\\]+}}baremetal"
 // CHECK-RV32-LIBSTDCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}Inputs{{[/\\]+}}basic_riscv32_tree{{[/\\]+}}riscv32-unknown-elf{{[/\\]+}}lib"
 // CHECK-RV32-LIBSTDCXX-SAME: "-lstdc++" "-lsupc++" "-lunwind"
 // CHECK-RV32-LIBSTDCXX-SAME: "-lc" "-lm" "-lclang_rt.builtins-riscv32"
@@ -230,7 +230,7 @@
 // RUN:     -nodefaultlibs \
 // RUN:   | FileCheck --check-prefix=CHECK-RV64-NDL %s
 // CHECK-RV64-NDL: "{{[^"]*}}ld{{(\.(lld|bfd|gold))?}}{{(\.exe)?}}" "{{.*}}.o" "-Bstatic"
-// CHECK-RV64-NDL-SAME: "-L{{[^"]*}}{{[/\\]+}}lib{{(64)?}}{{[/\\]+}}clang{{[/\\]+}}{{.*}}{{[/\\]+}}lib{{[/\\]+}}baremetal"
+// CHECK-RV64-NDL-SAME: "-L{{[^"]*}}{{[/\\]+}}lib{{(64|x32)?}}{{[/\\]+}}clang{{[/\\]+}}{{.*}}{{[/\\]+}}lib{{[/\\]+}}baremetal"
 // CHECK-RV64-NDL-SAME: "-L{{[^"]*}}{{[/\\]+}}Inputs{{[/\\]+}}basic_riscv64_tree{{[/\\]+}}riscv64-unknown-elf{{[/\\]+}}lib"
 // CHECK-RV64-NDL-SAME: "-o" "{{.*}}.o"
 
diff --git a/clang/test/Driver/cl-options.c b/clang/test/Driver/cl-options.c
--- a/clang/test/Driver/cl-options.c
+++ b/clang/test/Driver/cl-options.c
@@ -118,7 +118,7 @@
 // RUN: %clang_cl /imsvcmyincludedir -### -- %s 2>&1 | FileCheck -check-prefix=SLASH_imsvc %s
 // RUN: %clang_cl /imsvc myincludedir -### -- %s 2>&1 | FileCheck -check-prefix=SLASH_imsvc %s
 // Clang's resource header directory should be first:
-// SLASH_imsvc: "-internal-isystem" "{{[^"]*}}lib{{(64)?/|\\\\}}clang{{[^"]*}}include"
+// SLASH_imsvc: "-internal-isystem" "{{[^"]*}}lib{{(64|x32)?/|\\\\}}clang{{[^"]*}}include"
 // SLASH_imsvc: "-internal-isystem" "myincludedir"
 
 // RUN: %clang_cl /J -### -- %s 2>&1 | FileCheck -check-prefix=J %s
diff --git a/clang/test/Preprocessor/iwithprefix.c b/clang/test/Preprocessor/iwithprefix.c
--- a/clang/test/Preprocessor/iwithprefix.c
+++ b/clang/test/Preprocessor/iwithprefix.c
@@ -9,7 +9,7 @@
 
 // CHECK: #include <...> search starts here:
 // CHECK: {{.*}}.tmps/first
-// CHECK: {{/|\\}}lib{{(32|64)?}}{{/|\\}}clang{{/|\\}}{{[.0-9]+}}{{/|\\}}include
+// CHECK: {{/|\\}}lib{{(32|64|x32)?}}{{/|\\}}clang{{/|\\}}{{[.0-9]+}}{{/|\\}}include
 // CHECK: {{.*}}.tmps/second
 // CHECK-NOT: {{.*}}.tmps