================
@@ -1145,31 +1169,71 @@ struct AAAMDWavesPerEU : public AAAMDSizeRangeAttribute
{
auto &InfoCache = static_cast<AMDGPUInformationCache &>(A.getInfoCache());
ChangeStatus Change = ChangeStatus::UNCHANGED;
+ Function *F = getAssociatedFunction();
+
+ const auto *AAFlatWorkGroupSize = A.getAAFor<AAAMDFlatWorkGroupSize>(
+ *this, IRPosition::function(*F), DepClassTy::REQUIRED);
+ if (!AAFlatWorkGroupSize || !AAFlatWorkGroupSize->isValidState()) {
+ LLVM_DEBUG(
+ dbgs() << '[' << getName()
+ << "] AAAMDFlatWorkGroupSize is unavailable or invalid.\n");
+ return ChangeStatus::UNCHANGED;
+ }
+
+ if (AAFlatWorkGroupSize->isAtInitialState()) {
+ LLVM_DEBUG(dbgs() << '[' << getName()
+ << "] AAAMDFlatWorkGroupSize is still at initial "
+ "state. Skip the update.\n");
+ return ChangeStatus::UNCHANGED;
+ }
----------------
shiltian wrote:
There are four states to consider: valid, invalid, best, and worst. An AA
typically begins in the _best_ state and transitions toward a "worse" state
until reaching the _worst_ state. For most AAs, the invalid state is the worst
state, but this is not always true, especially for the `IntegerRangeState`,
which we use extensively here.
In the case of `IntegerRangeState`, the worst state is considered invalid
**only if** `Known` is set to the worst value (`~0U` by default). Once `Known`
is modified, there is no longer invalid state, meaning that `manifest` will
always run, and half-baked values are likely to be added. This is why I avoided
updating `Known` in #113018 and all related PRs in this stack unless the
changes were definitive (i.e., all call sites were seen).
The situation becomes more complex because the _best_ state does not actually
represent a valid pair of values in terms of the attribute. However, it must
still be considered valid so that updates can occur, allowing `Assumed` to be
updated accordingly.
Complications arise further because this AA relies on another AA that uses
range state. Similarly, the _best_ state of the dependent AA is not a valid
pair of values either. If the dependent AA remains in its _best_ (or _initial_,
as introduced in this PR) state, we must skip the update, as its values are
effectively nonsensical.
https://github.com/llvm/llvm-project/pull/114726
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