[PoisonCheker] Support for out of bounds operands on shifts + insert/extractelement

These are sources of poison which don't come from flags, but are clearly documented in the LangRef.  Left off support for scalable vectors for the moment, but should be easy to add if anyone is interested.  

llvm-svn: 365543

1 files changed, 41 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Instrumentation/PoisonChecking.cpp b/llvm/lib/Transforms/Instrumentation/PoisonChecking.cpp
index 8e4c046c9f8..0c4e64bbc54 100644
--- a/llvm/lib/Transforms/Instrumentation/PoisonChecking.cpp
+++ b/llvm/lib/Transforms/Instrumentation/PoisonChecking.cpp
@@ -169,14 +169,54 @@ static void generatePoisonChecksForBinOp(Instruction &I,
     }
     break;
   }
+  case Instruction::AShr:
+  case Instruction::LShr:
+  case Instruction::Shl: {
+    Value *ShiftCheck =
+      B.CreateICmp(ICmpInst::ICMP_UGE, RHS,
+                   ConstantInt::get(RHS->getType(),
+                                    LHS->getType()->getScalarSizeInBits()));
+    Checks.push_back(ShiftCheck);
+    break;
+  }
   };
 }
 
 static Value* generatePoisonChecks(Instruction &I) {
   IRBuilder<> B(&I);
   SmallVector<Value*, 2> Checks;
-  if (isa<BinaryOperator>(I))
+  if (isa<BinaryOperator>(I) && !I.getType()->isVectorTy())
     generatePoisonChecksForBinOp(I, Checks);
+
+  // Handle non-binops seperately
+  switch (I.getOpcode()) {
+  default:
+    break;
+  case Instruction::ExtractElement: {
+    Value *Vec = I.getOperand(0);
+    if (Vec->getType()->getVectorIsScalable())
+      break;
+    Value *Idx = I.getOperand(1);
+    unsigned NumElts = Vec->getType()->getVectorNumElements();
+    Value *Check =
+      B.CreateICmp(ICmpInst::ICMP_UGE, Idx,
+                   ConstantInt::get(Idx->getType(), NumElts));
+    Checks.push_back(Check);
+    break;
+  }
+  case Instruction::InsertElement: {
+    Value *Vec = I.getOperand(0);
+    if (Vec->getType()->getVectorIsScalable())
+      break;
+    Value *Idx = I.getOperand(2);
+    unsigned NumElts = Vec->getType()->getVectorNumElements();
+    Value *Check =
+      B.CreateICmp(ICmpInst::ICMP_UGE, Idx,
+                   ConstantInt::get(Idx->getType(), NumElts));
+    Checks.push_back(Check);
+    break;
+  }
+  };
   return buildOrChain(B, Checks);
 }