diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -3416,10 +3416,12 @@
 def EB : Flag<["-"], "EB">, Alias<mbig_endian>;
 def m16 : Flag<["-"], "m16">, Group<m_Group>, Flags<[NoXarchOption, CoreOption]>;
 def m32 : Flag<["-"], "m32">, Group<m_Group>, Flags<[NoXarchOption, CoreOption]>;
+def maix32 : Flag<["-"], "maix32">, Group<m_Group>, Flags<[NoXarchOption]>;
 def mqdsp6_compat : Flag<["-"], "mqdsp6-compat">, Group<m_Group>, Flags<[NoXarchOption,CC1Option]>,
   HelpText<"Enable hexagon-qdsp6 backward compatibility">,
   MarshallingInfoFlag<LangOpts<"HexagonQdsp6Compat">>;
 def m64 : Flag<["-"], "m64">, Group<m_Group>, Flags<[NoXarchOption, CoreOption]>;
+def maix64 : Flag<["-"], "maix64">, Group<m_Group>, Flags<[NoXarchOption]>;
 def mx32 : Flag<["-"], "mx32">, Group<m_Group>, Flags<[NoXarchOption, CoreOption]>;
 def mabi_EQ : Joined<["-"], "mabi=">, Group<m_Group>;
 def miamcu : Flag<["-"], "miamcu">, Group<m_Group>, Flags<[NoXarchOption, CoreOption]>,
diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -594,13 +594,21 @@
     }
   }
 
+  // The `-maix[32|64]` flags are only valid for AIX targets.
+  if (Arg *A = Args.getLastArgNoClaim(options::OPT_maix32, options::OPT_maix64);
+      A && !Target.isOSAIX())
+    D.Diag(diag::err_drv_unsupported_opt_for_target)
+        << A->getAsString(Args) << Target.str();
+
   // Handle pseudo-target flags '-m64', '-mx32', '-m32' and '-m16'.
   Arg *A = Args.getLastArg(options::OPT_m64, options::OPT_mx32,
-                           options::OPT_m32, options::OPT_m16);
+                           options::OPT_m32, options::OPT_m16,
+                           options::OPT_maix32, options::OPT_maix64);
   if (A) {
     llvm::Triple::ArchType AT = llvm::Triple::UnknownArch;
 
-    if (A->getOption().matches(options::OPT_m64)) {
+    if (A->getOption().matches(options::OPT_m64) ||
+        A->getOption().matches(options::OPT_maix64)) {
       AT = Target.get64BitArchVariant().getArch();
       if (Target.getEnvironment() == llvm::Triple::GNUX32)
         Target.setEnvironment(llvm::Triple::GNU);
@@ -613,7 +621,8 @@
         Target.setEnvironment(llvm::Triple::MuslX32);
       else
         Target.setEnvironment(llvm::Triple::GNUX32);
-    } else if (A->getOption().matches(options::OPT_m32)) {
+    } else if (A->getOption().matches(options::OPT_m32) ||
+               A->getOption().matches(options::OPT_maix32)) {
       AT = Target.get32BitArchVariant().getArch();
       if (Target.getEnvironment() == llvm::Triple::GNUX32)
         Target.setEnvironment(llvm::Triple::GNU);
diff --git a/clang/test/Driver/aix-maix.c b/clang/test/Driver/aix-maix.c
new file mode 100644
--- /dev/null
+++ b/clang/test/Driver/aix-maix.c
@@ -0,0 +1,17 @@
+// Check GCC AIX bitmode compat options.
+
+// RUN: %clang -target powerpc-ibm-aix -maix64 -### -c %s 2>&1 | \
+// RUN:   FileCheck --check-prefix=CHECK64 %s
+
+// RUN: %clang -target powerpc64-ibm-aix -maix32 -### -c %s 2>&1 | \
+// RUN:   FileCheck --check-prefix=CHECK32 %s
+
+// RUN: %clang -target powerpc-unknown-linux -maix64 -### -c %s 2>&1 | \
+// RUN:   FileCheck --check-prefix=ERROR %s
+
+// RUN: %clang -target powerpc64-unknown-linux -maix32 -### -c %s 2>&1 | \
+// RUN:   FileCheck --check-prefix=ERROR %s
+
+// CHECK32: Target: powerpc-ibm-aix
+// CHECK64: Target: powerpc64-ibm-aix
+// ERROR: error: unsupported option '-maix