diff --git a/clang/lib/Driver/ToolChain.cpp b/clang/lib/Driver/ToolChain.cpp
--- a/clang/lib/Driver/ToolChain.cpp
+++ b/clang/lib/Driver/ToolChain.cpp
@@ -662,7 +662,8 @@
   if (D.IsFlangMode() && getDriver().ShouldUseFlangCompiler(JA)) return getFlang();
   if (getDriver().ShouldUseClangCompiler(JA)) return getClang();
   Action::ActionClass AC = JA.getKind();
-  if (AC == Action::AssembleJobClass && useIntegratedAs())
+  if (AC == Action::AssembleJobClass && useIntegratedAs() &&
+      !getTriple().isOSAIX())
     return getClangAs();
   return getTool(AC);
 }
diff --git a/clang/lib/Driver/ToolChains/AIX.h b/clang/lib/Driver/ToolChains/AIX.h
--- a/clang/lib/Driver/ToolChains/AIX.h
+++ b/clang/lib/Driver/ToolChains/AIX.h
@@ -97,8 +97,10 @@
 protected:
   Tool *buildAssembler() const override;
   Tool *buildLinker() const override;
+  Tool *getTool(Action::ActionClass AC) const override;
 
 private:
+  mutable std::unique_ptr<Tool> Assembler;
   llvm::StringRef GetHeaderSysroot(const llvm::opt::ArgList &DriverArgs) const;
   bool ParseInlineAsmUsingAsmParser;
 };
diff --git a/clang/lib/Driver/ToolChains/AIX.cpp b/clang/lib/Driver/ToolChains/AIX.cpp
--- a/clang/lib/Driver/ToolChains/AIX.cpp
+++ b/clang/lib/Driver/ToolChains/AIX.cpp
@@ -416,6 +416,19 @@
   return ToolChain::RLT_CompilerRT;
 }
 
+Tool *AIX::getTool(Action::ActionClass AC) const {
+  switch (AC) {
+  default:
+    break;
+  // AIX always uses system assembler to compile assembly files.
+  case Action::AssembleJobClass:
+    if (!Assembler)
+      Assembler.reset(buildAssembler());
+    return Assembler.get();
+  }
+  return ToolChain::getTool(AC);
+}
+
 auto AIX::buildAssembler() const -> Tool * { return new aix::Assembler(*this); }
 
 auto AIX::buildLinker() const -> Tool * { return new aix::Linker(*this); }
diff --git a/clang/test/Driver/aix-assembler.s b/clang/test/Driver/aix-assembler.s
new file mode 100644
--- /dev/null
+++ b/clang/test/Driver/aix-assembler.s
@@ -0,0 +1,31 @@
+
+// Check powerpc64-ibm-aix7.1.0.0, 64-bit.
+// RUN: %clang %s -### -c -fintegrated-as 2>&1 \
+// RUN:         --target=powerpc64-ibm-aix7.1.0.0 \
+// RUN:   | FileCheck --check-prefixes=AS64,CHECK %s
+
+// RUN: %clang %s -### -c 2>&1 \
+// RUN:         --target=powerpc64-ibm-aix7.1.0.0 \
+// RUN:   | FileCheck --check-prefixes=AS64,CHECK %s
+
+// RUN: %clang %s -### -c -fno-integrated-as 2>&1 \
+// RUN:         --target=powerpc64-ibm-aix7.1.0.0 \
+// RUN:   | FileCheck --check-prefixes=AS64,CHECK %s
+
+// Check powerpc-ibm-aix7.1.0.0, 32-bit.
+// RUN: %clang %s -### -c -fintegrated-as 2>&1 \
+// RUN:         --target=powerpc-ibm-aix7.1.0.0 \
+// RUN:   | FileCheck --check-prefixes=AS32,CHECK %s
+
+// RUN: %clang %s -### -c 2>&1 \
+// RUN:         --target=powerpc-ibm-aix7.1.0.0 \
+// RUN:   | FileCheck --check-prefixes=AS32,CHECK %s
+
+// RUN: %clang %s -### -c 2>&1 -fno-integrated-as \
+// RUN:         --target=powerpc-ibm-aix7.1.0.0 \
+// RUN:   | FileCheck --check-prefixes=AS32,CHECK %s
+
+// CHECK: "{{.*}}as{{(.exe)?}}"
+// AS32: "-a32"
+// AS64: "-a64"
+// CHECK: "-many"