[PATCH] D157468: [RISCV] Add bounds check before use on returned iterator.

[Anmol P. Paralkar via Phabricator via llvm-commits]

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Check iterator validity before use; fixes crash on internal benchmark.


https://reviews.llvm.org/D157468

Files:
  llvm/lib/Target/RISCV/RISCVPushPopOptimizer.cpp


Index: llvm/lib/Target/RISCV/RISCVPushPopOptimizer.cpp
===================================================================
--- llvm/lib/Target/RISCV/RISCVPushPopOptimizer.cpp
+++ llvm/lib/Target/RISCV/RISCVPushPopOptimizer.cpp
@@ -132,8 +132,10 @@
   for (auto &MBB : Fn) {
     MachineBasicBlock::iterator MBBI = containsPop(MBB);
     MachineBasicBlock::iterator NextI = next_nodbg(MBBI, MBB.end());
-    if (MBBI != MBB.end() && NextI->getOpcode() == RISCV::PseudoRET)
+    if (MBBI != MBB.end() && NextI != MBB.end() &&
+        NextI->getOpcode() == RISCV::PseudoRET) {
       Modified |= usePopRet(MBBI, NextI, adjustRetVal(MBBI));
+    }
   }
   return Modified;
 }


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