diff --git a/llvm/lib/Target/PowerPC/MCTargetDesc/PPCInstPrinter.cpp b/llvm/lib/Target/PowerPC/MCTargetDesc/PPCInstPrinter.cpp
--- a/llvm/lib/Target/PowerPC/MCTargetDesc/PPCInstPrinter.cpp
+++ b/llvm/lib/Target/PowerPC/MCTargetDesc/PPCInstPrinter.cpp
@@ -80,6 +80,28 @@
     return;
   }
 
+  // The xxspltd extended mnemonic can get assembled improperly by the system
+  // assembler. Emit the full xxpermdi instruction instead.
+  if (TT.isOSAIX() && (MI->getOpcode() == PPC::XXPERMDI)) {
+    assert(MI->getNumOperands() == 4 && MI->getOperand(1).isReg() &&
+           MI->getOperand(2).isReg() && MI->getOperand(3).isImm() &&
+           "Unexpected operands on XXPERMDI");
+    int64_t Imm = MI->getOperand(3).getImm();
+    if (MI->getOperand(1).getReg() == MI->getOperand(2).getReg() &&
+        (Imm == 0 || Imm == 3)) {
+      // emit and return
+      O << "\txxpermdi ";
+      printOperand(MI, 0, O);
+      O << ", ";
+      printOperand(MI, 1, O);
+      O << ", ";
+      printOperand(MI, 2, O);
+      O << ", ";
+      printOperand(MI, 3, O);
+      return;
+    }
+  }
+
   // Check if the last operand is an expression with the variant kind
   // VK_PPC_PCREL_OPT. If this is the case then this is a linker optimization
   // relocation and the .reloc directive needs to be added.
diff --git a/llvm/test/CodeGen/PowerPC/vec_xxpermdi_mnemonics.ll b/llvm/test/CodeGen/PowerPC/vec_xxpermdi_mnemonics.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/PowerPC/vec_xxpermdi_mnemonics.ll
@@ -0,0 +1,58 @@
+; RUN: llc -mtriple powerpc64-ibm-aix-xcoff -mcpu=pwr8 --vec-extabi < %s | FileCheck --check-prefixes=CHECK,AIX %s
+; RUN: llc -mtriple powerpc-ibm-aix-xcoff -mcpu=pwr8 --vec-extabi < %s | FileCheck --check-prefixes=CHECK,AIX %s
+; RUN: llc -mtriple powerpc64-unknown-linux-gnu -mcpu=pwr8 --vec-extabi < %s | FileCheck --check-prefixes=CHECK,LINUX  %s
+
+define <2 x double> @splat1(<2 x double> %A, <2 x double> %B) {
+entry:
+  %0 = shufflevector <2 x double> %B, <2 x double> undef, <2 x i32> <i32 0, i32 0>
+  ret <2 x double> %0
+}
+
+; CHECK-LABEL: splat1
+; AIX: xxpermdi 34, 35, 35, 0
+; LINUX: xxspltd 34, 35, 0
+
+define <2 x double> @splat2(<2 x double> %A, <2 x double> %B) {
+entry:
+  %0 = shufflevector <2 x double> %B, <2 x double> undef, <2 x i32> <i32 1, i32 1>
+  ret <2 x double> %0
+}
+
+; CHECK-LABEL: splat2
+; AIX: xxpermdi 34, 35, 35, 3
+; LINUX: xxspltd 34, 35, 1
+
+define <2 x double> @swap(<2 x double> %A, <2 x double> %B) {
+entry:
+  %0 = shufflevector <2 x double> %B, <2 x double> undef, <2 x i32> <i32 1, i32 0>
+  ret <2 x double> %0
+}
+
+; CHECK-LABEL: swap
+; CHECK: xxswapd 34, 35
+
+define <2 x double> @identity(<2 x double> %A, <2 x double> %B) {
+entry:
+  %0 = shufflevector <2 x double> %B, <2 x double> undef, <2 x i32> <i32 0, i32 1>
+  ret <2 x double> %0
+}
+; CHECK-LABEL: identity
+; CHECK: vmr 2, 3
+
+define <2 x double> @mergehi(<2 x double> %A, <2 x double> %B) {
+entry:
+  %0 = shufflevector <2 x double> %A, <2 x double> %B, <2 x i32> <i32 0, i32 2>
+  ret <2 x double> %0
+}
+
+; CHECK-LABEL: mergehi
+; CHECK: xxmrghd 34, 34, 35
+
+define <2 x double> @mergelo(<2 x double> %A, <2 x double> %B) {
+entry:
+  %0 = shufflevector <2 x double> %A, <2 x double> %B, <2 x i32> <i32 1, i32 3>
+  ret <2 x double> %0
+}
+
+; CHECK-LABEL: mergelo
+; CHECK: xxmrgld 34, 34, 35