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[VPlan] Factor out logic to check if recipe is dead (NFCI).

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In preparation to use the helper in more places.
This commit is contained in:
Florian Hahn 2024-04-03 14:22:40 +01:00
parent 95f9b083d0
commit e329b68413
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GPG Key ID: 9E54DEA47A8F4434
1 changed files with 22 additions and 16 deletions
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38
llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
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@ -472,6 +472,26 @@ static void removeRedundantCanonicalIVs(VPlan &Plan) {
}
}
/// Returns true if \p R is dead and can be removed.
static bool isDeadRecipe(VPRecipeBase &R) {
using namespace llvm::PatternMatch;
// Do remove conditional assume instructions as their conditions may be
// flattened.
auto *RepR = dyn_cast<VPReplicateRecipe>(&R);
bool IsConditionalAssume =
RepR && RepR->isPredicated() &&
match(RepR->getUnderlyingInstr(), m_Intrinsic<Intrinsic::assume>());
if (IsConditionalAssume)
return true;
if (R.mayHaveSideEffects())
return false;
// Recipe is dead if no user keeps the recipe alive.
return all_of(R.definedValues(),
[](VPValue *V) { return V->getNumUsers() == 0; });
}
static void removeDeadRecipes(VPlan &Plan) {
ReversePostOrderTraversal<VPBlockDeepTraversalWrapper<VPBlockBase *>> RPOT(
Plan.getEntry());
@ -480,22 +500,8 @@ static void removeDeadRecipes(VPlan &Plan) {
// The recipes in the block are processed in reverse order, to catch chains
// of dead recipes.
for (VPRecipeBase &R : make_early_inc_range(reverse(*VPBB))) {
// A user keeps R alive:
if (any_of(R.definedValues(),
[](VPValue *V) { return V->getNumUsers(); }))
continue;
using namespace llvm::PatternMatch;
// Having side effects keeps R alive, but do remove conditional assume
// instructions as their conditions may be flattened.
auto *RepR = dyn_cast<VPReplicateRecipe>(&R);
bool IsConditionalAssume =
RepR && RepR->isPredicated() &&
match(RepR->getUnderlyingInstr(), m_Intrinsic<Intrinsic::assume>());
if (R.mayHaveSideEffects() && !IsConditionalAssume)
continue;
R.eraseFromParent();
if (isDeadRecipe(R))
R.eraseFromParent();
}
}
}