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
@@ -2941,31 +2941,27 @@
   if (!getVFS().exists(IncludeDir))
     return false;
 
+  // Debian native gcc uses g++-multiarch-incdir.diff which uses
+  // include/x86_64-linux-gnu/c++/10$IncludeSuffix instead of
+  // include/c++/10/x86_64-linux-gnu$IncludeSuffix.
+  std::string Dir = IncludeDir.str();
+  StringRef Include =
+      llvm::sys::path::parent_path(llvm::sys::path::parent_path(Dir));
+  std::string Path =
+      (Include + "/" + Triple + Dir.substr(Include.size()) + IncludeSuffix)
+          .str();
+  if (DetectDebian && !getVFS().exists(Path))
+    return false;
+
   // GPLUSPLUS_INCLUDE_DIR
   addSystemInclude(DriverArgs, CC1Args, IncludeDir);
   // GPLUSPLUS_TOOL_INCLUDE_DIR. If Triple is not empty, add a target-dependent
   // include directory.
-  if (!Triple.empty()) {
-    if (DetectDebian) {
-      // Debian native gcc has an awful patch g++-multiarch-incdir.diff which
-      // uses include/x86_64-linux-gnu/c++/10$IncludeSuffix instead of
-      // include/c++/10/x86_64-linux-gnu$IncludeSuffix.
-      std::string Dir = IncludeDir.str();
-      StringRef Include =
-          llvm::sys::path::parent_path(llvm::sys::path::parent_path(Dir));
-      std::string Path =
-          (Include + "/" + Triple + Dir.substr(Include.size()) + IncludeSuffix)
-              .str();
-      if (getVFS().exists(Path))
-        addSystemInclude(DriverArgs, CC1Args, Path);
-      else
-        addSystemInclude(DriverArgs, CC1Args,
-                         IncludeDir + "/" + Triple + IncludeSuffix);
-    } else {
-      addSystemInclude(DriverArgs, CC1Args,
-                       IncludeDir + "/" + Triple + IncludeSuffix);
-    }
-  }
+  if (DetectDebian)
+    addSystemInclude(DriverArgs, CC1Args, Path);
+  else if (!Triple.empty())
+    addSystemInclude(DriverArgs, CC1Args,
+                     IncludeDir + "/" + Triple + IncludeSuffix);
   // GPLUSPLUS_BACKWARD_INCLUDE_DIR
   addSystemInclude(DriverArgs, CC1Args, IncludeDir + "/backward");
   return true;
@@ -2985,7 +2981,7 @@
   const Multilib &Multilib = GCCInstallation.getMultilib();
   const GCCVersion &Version = GCCInstallation.getVersion();
 
-  // Try /../$triple/include/c++/$version then /../include/c++/$version.
+  // Try /../$triple/include/c++/$version (gcc --print-multiarch is not empty).
   if (addLibStdCXXIncludePaths(
           LibDir.str() + "/../" + TripleStr + "/include/c++/" + Version.Text,
           TripleStr, Multilib.includeSuffix(), DriverArgs, CC1Args))
@@ -2997,6 +2993,12 @@
                                DriverArgs, CC1Args, /*Debian=*/true))
     return true;
 
+  // Try /../include/c++/$version (gcc --print-multiarch is empty).
+  if (addLibStdCXXIncludePaths(LibDir.str() + "/../include/c++/" + Version.Text,
+                               TripleStr, Multilib.includeSuffix(), DriverArgs,
+                               CC1Args))
+    return true;
+
   // Otherwise, fall back on a bunch of options which don't use multiarch
   // layouts for simplicity.
   const std::string LibStdCXXIncludePathCandidates[] = {
diff --git a/clang/test/Driver/Inputs/archlinux_i686_tree/lib/.keep b/clang/test/Driver/Inputs/archlinux_i686_tree/lib/.keep
new file mode 100644
diff --git a/clang/test/Driver/Inputs/archlinux_i686_tree/usr/include/c++/11.1.0/backward/.keep b/clang/test/Driver/Inputs/archlinux_i686_tree/usr/include/c++/11.1.0/backward/.keep
new file mode 100644
diff --git a/clang/test/Driver/Inputs/archlinux_i686_tree/usr/include/c++/11.1.0/i686-pc-linux-gnu/.keep b/clang/test/Driver/Inputs/archlinux_i686_tree/usr/include/c++/11.1.0/i686-pc-linux-gnu/.keep
new file mode 100644
diff --git a/clang/test/Driver/Inputs/archlinux_i686_tree/usr/lib/crt1.o b/clang/test/Driver/Inputs/archlinux_i686_tree/usr/lib/crt1.o
new file mode 100644
diff --git a/clang/test/Driver/Inputs/archlinux_i686_tree/usr/lib/crti.o b/clang/test/Driver/Inputs/archlinux_i686_tree/usr/lib/crti.o
new file mode 100644
diff --git a/clang/test/Driver/Inputs/archlinux_i686_tree/usr/lib/crtn.o b/clang/test/Driver/Inputs/archlinux_i686_tree/usr/lib/crtn.o
new file mode 100644
diff --git a/clang/test/Driver/Inputs/archlinux_i686_tree/usr/lib/gcc/i686-pc-linux-gnu/11.1.0/crtbegin.o b/clang/test/Driver/Inputs/archlinux_i686_tree/usr/lib/gcc/i686-pc-linux-gnu/11.1.0/crtbegin.o
new file mode 100644
diff --git a/clang/test/Driver/Inputs/archlinux_i686_tree/usr/lib/gcc/i686-pc-linux-gnu/11.1.0/crtend.o b/clang/test/Driver/Inputs/archlinux_i686_tree/usr/lib/gcc/i686-pc-linux-gnu/11.1.0/crtend.o
new file mode 100644
diff --git a/clang/test/Driver/linux-cross.cpp b/clang/test/Driver/linux-cross.cpp
--- a/clang/test/Driver/linux-cross.cpp
+++ b/clang/test/Driver/linux-cross.cpp
@@ -1,5 +1,27 @@
 // UNSUPPORTED: system-windows
 
+/// Test native GCC installation on Arch Linux i686.
+// RUN: %clang -### %s --target=i686-linux-gnu --sysroot=%S/Inputs/archlinux_i686_tree \
+// RUN:   -ccc-install-dir %S/Inputs/basic_linux_tree/usr/bin -resource-dir=%S/Inputs/resource_dir \
+// RUN:   --stdlib=platform --rtlib=platform 2>&1 | FileCheck %s --check-prefix=ARCH_I686
+// ARCH_I686:      "-resource-dir" "[[RESOURCE:[^"]+]]"
+// ARCH_I686:      "-internal-isystem"
+// ARCH_I686-SAME: {{^}} "[[SYSROOT:[^"]+]]/usr/lib/gcc/i686-pc-linux-gnu/11.1.0/../../../../include/c++/11.1.0"
+// ARCH_I686-SAME: {{^}} "-internal-isystem" "[[SYSROOT:[^"]+]]/usr/lib/gcc/i686-pc-linux-gnu/11.1.0/../../../../include/c++/11.1.0/i686-pc-linux-gnu"
+// ARCH_I686-SAME: {{^}} "-internal-isystem" "[[SYSROOT:[^"]+]]/usr/lib/gcc/i686-pc-linux-gnu/11.1.0/../../../../include/c++/11.1.0/backward"
+// ARCH_I686-SAME: {{^}} "-internal-isystem" "[[RESOURCE]]/include"
+// ARCH_I686-SAME: {{^}} "-internal-isystem" "[[SYSROOT]]/usr/local/include"
+/// This resolves to /usr/i686-linux-gnu/include. Because it does not exist,
+/// having it does no harm albeit not ideal.
+// ARCH_I686-SAME: {{^}} "-internal-isystem" "[[SYSROOT:[^"]+]]/usr/lib/gcc/i686-pc-linux-gnu/11.1.0/../../../../i686-pc-linux-gnu/include"
+// ARCH_I686:      "-internal-externc-isystem"
+// ARCH_I686-SAME: {{^}} "[[SYSROOT]]/include"
+// ARCH_I686-SAME: {{^}} "-internal-externc-isystem" "[[SYSROOT]]/usr/include"
+// ARCH_I686:      "-L
+// ARCH_I686-SAME: {{^}}[[SYSROOT]]/usr/lib/gcc/i686-pc-linux-gnu/11.1.0"
+// ARCH_I686-SAME: {{^}} "-L[[SYSROOT]]/lib"
+// ARCH_I686-SAME: {{^}} "-L[[SYSROOT]]/usr/lib"
+
 /// Test native x86-64 in the tree.
 // RUN: %clang -### %s --target=x86_64-linux-gnu --sysroot=%S/Inputs/debian_multiarch_tree \
 // RUN:   -ccc-install-dir %S/Inputs/basic_linux_tree/usr/bin -resource-dir=%S/Inputs/resource_dir \