[PATCH] D112980: [LoopInfo] Fix a bug in the function getInductionVariable

[Florian Hahn via Phabricator via llvm-commits]

fhahn added a comment.

> The induction variable will be the first phi of the loop, and this does not match the logic of this function.

Is the code relying on the IV being the first phi in the loop? That is not a guarantee that can be relied on I think.



================
Comment at: llvm/lib/Analysis/LoopInfo.cpp:312
 
-    Instruction *StepInst = IndDesc.getInductionBinOp();
+    BasicBlock *Latch = this->getLoopLatch();
+    Value *StepInst = IndVar.getIncomingValueForBlock(Latch);
----------------
nit: no need for `this->`?


================
Comment at: llvm/unittests/Analysis/LoopInfoTest.cpp:1551
+
+TEST(LoopInfoTest, LoopInductionVariable) {
+  const char *ModuleStr =
----------------
Can you clean up the IR? There are multiple things that should not be needed, like 

`"; Function Attrs:`

`dso_local sigext`

the metadata and more.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D112980/new/

https://reviews.llvm.org/D112980