diff --git a/test/tools/llvm-exegesis/PowerPC/unsupported-opcode.s b/test/tools/llvm-exegesis/PowerPC/unsupported-opcode.s
new file mode 100644
index 0000000..67348ef
--- /dev/null
+++ b/test/tools/llvm-exegesis/PowerPC/unsupported-opcode.s
@@ -0,0 +1,3 @@
+# RUN: llvm-exegesis -mode=latency -opcode-name=SELECT_I8 2>&1 | FileCheck %s
+
+CHECK: Unsupported opcode: isPseudo/usesCustomInserter
diff --git a/tools/llvm-exegesis/lib/SerialSnippetGenerator.cpp b/tools/llvm-exegesis/lib/SerialSnippetGenerator.cpp
index 504e7bd..f5940bd 100644
--- a/tools/llvm-exegesis/lib/SerialSnippetGenerator.cpp
+++ b/tools/llvm-exegesis/lib/SerialSnippetGenerator.cpp
@@ -51,7 +51,7 @@
     const Instruction &OtherInstr = State.getIC().getInstr(OtherOpcode);
     const MCInstrDesc &OtherInstrDesc = OtherInstr.Description;
     // Ignore instructions that we cannot run.
-    if (OtherInstrDesc.isPseudo() ||
+    if (OtherInstrDesc.isPseudo() || OtherInstrDesc.usesCustomInsertionHook() ||
         OtherInstrDesc.isBranch() || OtherInstrDesc.isIndirectBranch() ||
         OtherInstrDesc.isCall() || OtherInstrDesc.isReturn()) {
           continue;
diff --git a/tools/llvm-exegesis/llvm-exegesis.cpp b/tools/llvm-exegesis/llvm-exegesis.cpp
index 2d20d0e..9cbcc1b 100644
--- a/tools/llvm-exegesis/llvm-exegesis.cpp
+++ b/tools/llvm-exegesis/llvm-exegesis.cpp
@@ -251,8 +251,9 @@
   const Instruction &Instr = State.getIC().getInstr(Opcode);
   const MCInstrDesc &InstrDesc = Instr.Description;
   // Ignore instructions that we cannot run.
-  if (InstrDesc.isPseudo())
-    return make_error<Failure>("Unsupported opcode: isPseudo");
+  if (InstrDesc.isPseudo() || InstrDesc.usesCustomInsertionHook())
+    return make_error<Failure>(
+        "Unsupported opcode: isPseudo/usesCustomInserter");
   if (InstrDesc.isBranch() || InstrDesc.isIndirectBranch())
     return make_error<Failure>("Unsupported opcode: isBranch/isIndirectBranch");
   if (InstrDesc.isCall() || InstrDesc.isReturn())