[PATCH] D144125: [VPlan] VPWidenIntOrFpInductionRecipe inherits from VPHeaderPHIRecipe

[Ayal Zaks via Phabricator via llvm-commits]

Ayal added a comment.

This change makes a lot of sense, except for getBackedgeValue() - see comment.



================
Comment at: llvm/lib/Transforms/Vectorize/VPlan.h:1142-1143
+  /// Returns the step value of the induction.
+  VPValue *getStepValue() { return getOperand(1); }
+  const VPValue *getStepValue() const { return getOperand(1); }
+
----------------
Now that `VPWidenIntOrFpInductionRecipe` inherits from `VPHeaderPHIRecipe`, it also inherits `getBackedgeValue()`, which should return a VPValue defined by some recipe - `getBackedgeRecipe()` - **inside** the loop. The default returns `getOperand(1)`. However, `VPWidenIntOrFpInductionRecipe` has no such VPValue nor recipe to return because it takes care of generating the corresponding IR code only during execution. Better override `getBackedgeValue()` and `getBackedgeRecipe()`, asserting they are unreachable/never called?
(`Step` which here serves as operand 1 instead is a value defined by a recipe in the loop preheader or constant - not a recipe.)


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Comment at: llvm/lib/Transforms/Vectorize/VPlan.h:1147-1152
+  TruncInst *getTruncInst() {
+    return Trunc;
+  }
+  const TruncInst *getTruncInst() const {
+    return Trunc;
+  }
----------------
nit: these should now be one liners.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D144125/new/

https://reviews.llvm.org/D144125