From e70783b86bf3427bccd3d0b8cec858b888b8c887 Mon Sep 17 00:00:00 2001
From: Martin Nowack <m.nowack@imperial.ac.uk>
Date: Sun, 29 Jul 2018 16:13:26 +0100
Subject: DivCheck Skip unneeded checks

Do not instrument divisions which do have a constant non-zero value.
---
 lib/Module/Checks.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

(limited to 'lib/Module/Checks.cpp')

diff --git a/lib/Module/Checks.cpp b/lib/Module/Checks.cpp
index a9ef0dd4..b6aadce4 100644
--- a/lib/Module/Checks.cpp
+++ b/lib/Module/Checks.cpp
@@ -47,6 +47,12 @@ bool DivCheckPass::runOnModule(Module &M) {
         if (opcode != Instruction::SDiv && opcode != Instruction::UDiv &&
             opcode != Instruction::SRem && opcode != Instruction::URem)
           continue;
+
+        // Check if the operand is constant and not zero, skip in that case.
+        const auto &operand = binOp->getOperand(1);
+        if (const auto &coOp = dyn_cast<llvm::Constant>(operand)) {
+          if (!coOp->isZeroValue())
+            continue;
         }
       }
     }
-- 
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