Index: llvm/lib/Target/PowerPC/MCTargetDesc/PPCInstPrinter.cpp
===================================================================
--- llvm/lib/Target/PowerPC/MCTargetDesc/PPCInstPrinter.cpp
+++ llvm/lib/Target/PowerPC/MCTargetDesc/PPCInstPrinter.cpp
@@ -596,8 +596,6 @@
 // showRegistersWithPrefix - This method determines whether registers
 // should be number-only or include the prefix.
 bool PPCInstPrinter::showRegistersWithPrefix() const {
-  if (TT.getOS() == Triple::AIX)
-    return false;
   return TT.isOSDarwin() || FullRegNamesWithPercent || FullRegNames;
 }
 
Index: llvm/test/CodeGen/PowerPC/reg-names.ll
===================================================================
--- llvm/test/CodeGen/PowerPC/reg-names.ll
+++ llvm/test/CodeGen/PowerPC/reg-names.ll
@@ -1,5 +1,6 @@
 ; RUN: llc -verify-machineinstrs -mtriple=powerpc64-unknown-linux-gnu < %s | FileCheck %s
 ; RUN: llc -verify-machineinstrs -mtriple=powerpc64-unknown-linux-gnu -ppc-asm-full-reg-names < %s | FileCheck -check-prefix=CHECK-FN %s
+; RUN: llc -verify-machineinstrs -mtriple=powerpc64-ibm-aix-xcoff -ppc-asm-full-reg-names < %s | FileCheck -check-prefix=CHECK-FN %s
 ; RUN: llc -verify-machineinstrs -mtriple=powerpc64-unknown-linux-gnu -ppc-reg-with-percent-prefix < %s | FileCheck -check-prefix=CHECK-PN %s
 
 define i64 @test1(i64 %a, i64 %b) {