Tentative fix for global-buffer-overflow caused by r188426. Found by AddressSanitizer

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188448 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/R600/AMDGPUISelDAGToDAG.cpp b/lib/Target/R600/AMDGPUISelDAGToDAG.cpp
index 22bdb90cca09e118e25be5973115b3d3e79281cb..77ca8856018f6c04b125619a236075908157ff39 100644 (file)
--- a/lib/Target/R600/AMDGPUISelDAGToDAG.cpp
+++ b/lib/Target/R600/AMDGPUISelDAGToDAG.cpp
@@ -115,7 +115,10 @@ const TargetRegisterClass *AMDGPUDAGToDAGISel::getOperandRegClass(SDNode *N,
   switch (N->getMachineOpcode()) {
   default: {
     const MCInstrDesc &Desc = TM.getInstrInfo()->get(N->getMachineOpcode());
-    int RegClass = Desc.OpInfo[Desc.getNumDefs() + OpNo].RegClass;
+    unsigned OpIdx = Desc.getNumDefs() + OpNo;
+    if (OpIdx >= Desc.getNumOperands())
+      return NULL;
+    int RegClass = Desc.OpInfo[OpIdx].RegClass;
     if (RegClass == -1) {
       return NULL;
     }