[PATCH] D76200: [VPlan] Use underlying value for printing, if available.

[Ayal Zaks via Phabricator via llvm-commits]

Ayal added inline comments.


================
Comment at: llvm/lib/Transforms/Vectorize/VPlan.cpp:588
     }
     for (auto Entry : Plan.Value2VPValue) {
       OS << "\\n";
----------------
fhahn wrote:
> Ayal wrote:
> > If now every VPValue that wraps a Value clearly says so in its name, does it hopefully make this "%vpA := %irX" part of "where:" redundant?
> I can drop that in a follow-up, if that's ok?
Sure, by all means.


================
Comment at: llvm/lib/Transforms/Vectorize/VPlan.cpp:818
+  const Value *UV = getUnderlyingValue();
+  if (UV && UV->hasName()) {
+    OS << "%vp." << UV->getName();
----------------
fhahn wrote:
> Ayal wrote:
> > Even if UV does not have a name, could we still indicate that VPValue wraps it; possibly by calling UV->printAsOperand()?
> Done! It required to add special handling for constants and also a bit of code to drop the % printed by printAsOperand, but now all underlying IR values should be printed consistently. A full list of the required changes can be found in the update comment.
Thanks!
Could this be simplified, by always printing "ir<X>" where X is whatever printAsOperand provides, which could be ir<%tmp>, ir<%5>, ir<7>, ir<void>,  letting the caller worry about not printing void?

And for VPValues w/o ingredients, print "vp<%x>" where x is the number assigned by SlotTracker? Currently this should be only BackedgeTakenCount, which ought to be assigned a meaningful name...


================
Comment at: llvm/lib/Transforms/Vectorize/VPlan.cpp:409
+  if (hasResult())
+    O << " = ";
 
----------------
Better call `printAsOperand(O, SlotTracker)` only when needed, i.e.,
```
  if (hasResult()) {
    printAsOperand(O, SlotTracker);
    O << " = ";
  }
```


================
Comment at: llvm/lib/Transforms/Vectorize/VPlan.cpp:892
+  const Value *UV = V->getUnderlyingValue();
+  if (!UV || !UV->hasName())
+    Slots[V] = NextSlot++;
----------------
Suffice to check now instead if `(!UV)`


================
Comment at: llvm/lib/Transforms/Vectorize/VPlan.h:739
+
+  bool hasResult() const {
+    if (const Value *UV = getUnderlyingValue())
----------------
Better look at the VPInstruction's Opcode to determine if it has a result?


================
Comment at: llvm/lib/Transforms/Vectorize/VPlan.h:1479
     assert(!Value2VPValue.count(V) && "Value already exists in VPlan");
     Value2VPValue[V] = new VPValue();
   }
----------------
Better record the underlying ingredient to be used when printing, by doing `new VPValue(V)` instead.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D76200/new/

https://reviews.llvm.org/D76200