[PATCH] D71660: [ValueTracking] isKnownNonZero() should take non-null-ness assumptions into consideration (PR43267)

[Nikita Popov via Phabricator via llvm-commits]

nikic added inline comments.


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Comment at: llvm/lib/Analysis/ValueTracking.cpp:572
+  // the control flow, not even CxtI itself.
+  for (BasicBlock::const_iterator I = BasicBlock::const_iterator(CxtI), IE(Inv);
        I != IE; ++I)
----------------
Does just `BasicBlock::const_iterator I(CxtI), IE(Inv);` work?


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Comment at: llvm/lib/Analysis/ValueTracking.cpp:611
+    ConstantInt *CI;
+    if (!match(RHS, m_ConstantInt(CI)))
+      return false;
----------------
Any particular reason to use m_ConstantInt() over m_APInt() here? The difference in vector handling?


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Comment at: llvm/lib/Analysis/ValueTracking.cpp:636
+    Value *Arg = I->getArgOperand(0);
+
+    ICmpInst *Cmp = dyn_cast<ICmpInst>(Arg);
----------------
nit: Unnecessary newline.


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Comment at: llvm/test/Transforms/InstCombine/assume.ll:272
 ; CHECK:       taken:
+; CHECK-NEXT:    [[LOAD:%.*]] = load i32*, i32** [[A:%.*]], align 8
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i32* [[LOAD]], null
----------------
I'm assuming that we first evaluate the icmp below, then the load is one-use and gets sunk. I'm wondering why the assume is not converted into `!nonnull` metadata after that, as the control dependence is now gone.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D71660/new/

https://reviews.llvm.org/D71660