[llvm] 9bc866c - [VPlan] Add recipe to handle SCEV expansion (NFC).
Florian Hahn via llvm-commits
llvm-commits at lists.llvm.org
Sun Feb 27 04:48:02 PST 2022
Author: Florian Hahn
Date: 2022-02-27T12:47:02Z
New Revision: 9bc866cc6f4fa01186e5ec8306d6b542962b27e9
URL: https://github.com/llvm/llvm-project/commit/9bc866cc6f4fa01186e5ec8306d6b542962b27e9
DIFF: https://github.com/llvm/llvm-project/commit/9bc866cc6f4fa01186e5ec8306d6b542962b27e9.diff
LOG: [VPlan] Add recipe to handle SCEV expansion (NFC).
This can be used to explicitly model VPValues that depend on SCEV
expansion, like the step for inductions.
Reviewed By: Ayal
Differential Revision: https://reviews.llvm.org/D116288
Added:
Modified:
llvm/lib/Transforms/Vectorize/VPlan.cpp
llvm/lib/Transforms/Vectorize/VPlan.h
llvm/lib/Transforms/Vectorize/VPlanValue.h
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/Vectorize/VPlan.cpp b/llvm/lib/Transforms/Vectorize/VPlan.cpp
index 072f78cf4a69c..55e0cc5c7df37 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlan.cpp
@@ -41,6 +41,7 @@
#include "llvm/Support/GraphWriter.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include "llvm/Transforms/Utils/ScalarEvolutionExpander.h"
#include <cassert>
#include <iterator>
#include <string>
@@ -1399,6 +1400,27 @@ void VPCanonicalIVPHIRecipe::print(raw_ostream &O, const Twine &Indent,
}
#endif
+void VPExpandSCEVRecipe::execute(VPTransformState &State) {
+ assert(!State.Instance && "cannot be used in per-lane");
+ const DataLayout &DL =
+ State.CFG.VectorPreHeader->getModule()->getDataLayout();
+ SCEVExpander Exp(SE, DL, "induction");
+ Value *Res = Exp.expandCodeFor(Expr, Expr->getType(),
+ State.CFG.VectorPreHeader->getTerminator());
+
+ for (unsigned Part = 0, UF = State.UF; Part < UF; ++Part)
+ State.set(this, Res, Part);
+}
+
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+void VPExpandSCEVRecipe::print(raw_ostream &O, const Twine &Indent,
+ VPSlotTracker &SlotTracker) const {
+ O << Indent << "EMIT ";
+ getVPSingleValue()->printAsOperand(O, SlotTracker);
+ O << " = EXPAND SCEV " << *Expr;
+}
+#endif
+
void VPWidenCanonicalIVRecipe::execute(VPTransformState &State) {
Value *CanonicalIV = State.get(getOperand(0), 0);
Type *STy = CanonicalIV->getType();
diff --git a/llvm/lib/Transforms/Vectorize/VPlan.h b/llvm/lib/Transforms/Vectorize/VPlan.h
index 6d2bee1686917..729df09ddaf88 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.h
+++ b/llvm/lib/Transforms/Vectorize/VPlan.h
@@ -1720,6 +1720,36 @@ class VPWidenMemoryInstructionRecipe : public VPRecipeBase, public VPValue {
}
};
+/// Recipe to expand a SCEV expression.
+/// TODO: Currently the recipe always expands the expression in the loop
+/// pre-header, but the recipe is currently placed in the header; place it in
+/// the pre-header once the latter is modeled in VPlan as a VPBasicBlock.
+class VPExpandSCEVRecipe : public VPRecipeBase, public VPValue {
+ const SCEV *Expr;
+ ScalarEvolution &SE;
+
+public:
+ VPExpandSCEVRecipe(const SCEV *Expr, ScalarEvolution &SE)
+ : VPRecipeBase(VPExpandSCEVSC, {}), VPValue(nullptr, this), Expr(Expr),
+ SE(SE) {}
+
+ ~VPExpandSCEVRecipe() override = default;
+
+ /// Method to support type inquiry through isa, cast, and dyn_cast.
+ static inline bool classof(const VPDef *D) {
+ return D->getVPDefID() == VPExpandSCEVSC;
+ }
+
+ /// Generate a canonical vector induction variable of the vector loop, with
+ void execute(VPTransformState &State) override;
+
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+ /// Print the recipe.
+ void print(raw_ostream &O, const Twine &Indent,
+ VPSlotTracker &SlotTracker) const override;
+#endif
+};
+
/// Canonical scalar induction phi of the vector loop. Starting at the specified
/// start value (either 0 or the resume value when vectorizing the epilogue
/// loop). VPWidenCanonicalIVRecipe represents the vector version of the
diff --git a/llvm/lib/Transforms/Vectorize/VPlanValue.h b/llvm/lib/Transforms/Vectorize/VPlanValue.h
index 5296d2b9485cc..3690e33efd2ad 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanValue.h
+++ b/llvm/lib/Transforms/Vectorize/VPlanValue.h
@@ -327,6 +327,7 @@ class VPDef {
/// type identification.
using VPRecipeTy = enum {
VPBranchOnMaskSC,
+ VPExpandSCEVSC,
VPInstructionSC,
VPInterleaveSC,
VPReductionSC,
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