[AMDGPU] fix failure on printing of non-existing instruction operands.

Differential revision: https://reviews.llvm.org/D23323

llvm-svn: 278665

llvm/lib/Target/AMDGPU/InstPrinter/AMDGPUInstPrinter.cpp

diff --git a/llvm/lib/Target/AMDGPU/InstPrinter/AMDGPUInstPrinter.cpp b/llvm/lib/Target/AMDGPU/InstPrinter/AMDGPUInstPrinter.cpp
index 2932d3b..7dd0f00 100644
--- a/llvm/lib/Target/AMDGPU/InstPrinter/AMDGPUInstPrinter.cpp
+++ b/llvm/lib/Target/AMDGPU/InstPrinter/AMDGPUInstPrinter.cpp
@@ -370,6 +370,11 @@
 void AMDGPUInstPrinter::printOperand(const MCInst *MI, unsigned OpNo,
                                      raw_ostream &O) {
 
+  if (OpNo >= MI->getNumOperands()) {
+    O << "/*Missing OP" << OpNo << "*/";
+    return;
+  }
+
   const MCOperand &Op = MI->getOperand(OpNo);
   if (Op.isReg()) {
     switch (Op.getReg()) {

llvm/test/MC/Disassembler/AMDGPU/missing_op.txt

diff --git a/llvm/test/MC/Disassembler/AMDGPU/missing_op.txt b/llvm/test/MC/Disassembler/AMDGPU/missing_op.txt
new file mode 100644
index 0000000..7c4e252
--- /dev/null
+++ b/llvm/test/MC/Disassembler/AMDGPU/missing_op.txt
@@ -0,0 +1,5 @@
+# RUN: llvm-mc -arch=amdgcn -mcpu=fiji -disassemble < %s | FileCheck %s -check-prefix=VI
+
+#TODO: this test will fail when we fix v_interp_p2_f32 signature, remove it then
+#VI: v_interp_p2_f32 16, [/*Missing OP1*/], /*Missing OP2*/, /*Missing OP3*/, /*Missing OP4*/
+0xd4 0x41 0x1d 0xd4