[VPlan] Remove SCEVToExpansion mapping (NFC).

[fhahn]

VPlan::SCEVToExpansion isn't needed any longer, as SCEV expansion de-duplication is handled locally in expandSCEVs.

[llvmbot]

@llvm/pr-subscribers-llvm-transforms

@llvm/pr-subscribers-vectorizers

Author: Florian Hahn (fhahn)

Changes

VPlan::SCEVToExpansion isn't needed any longer, as SCEV expansion de-duplication is handled locally in expandSCEVs.

---

Full diff: https://github.com/llvm/llvm-project/pull/164490.diff

2 Files Affected:

• (modified) llvm/lib/Transforms/Vectorize/VPlan.h (-14)
• (modified) llvm/lib/Transforms/Vectorize/VPlanUtils.cpp (-3)

diff --git a/llvm/lib/Transforms/Vectorize/VPlan.h b/llvm/lib/Transforms/Vectorize/VPlan.h
index 167ba553af599..38f49c1a5f84c 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.h
+++ b/llvm/lib/Transforms/Vectorize/VPlan.h
@@ -4166,11 +4166,6 @@ class VPlan {
   /// definitions are VPValues that hold a pointer to their underlying IR.
   SmallVector<VPValue *, 16> VPLiveIns;
 
-  /// Mapping from SCEVs to the VPValues representing their expansions.
-  /// NOTE: This mapping is temporary and will be removed once all users have
-  /// been modeled in VPlan directly.
-  DenseMap<const SCEV *, VPValue *> SCEVToExpansion;
-
   /// Blocks allocated and owned by the VPlan. They will be deleted once the
   /// VPlan is destroyed.
   SmallVector<VPBlockBase *> CreatedBlocks;
@@ -4427,15 +4422,6 @@ class VPlan {
   LLVM_DUMP_METHOD void dump() const;
 #endif
 
-  VPValue *getSCEVExpansion(const SCEV *S) const {
-    return SCEVToExpansion.lookup(S);
-  }
-
-  void addSCEVExpansion(const SCEV *S, VPValue *V) {
-    assert(!SCEVToExpansion.contains(S) && "SCEV already expanded");
-    SCEVToExpansion[S] = V;
-  }
-
   /// Clone the current VPlan, update all VPValues of the new VPlan and cloned
   /// recipes to refer to the clones, and return it.
   VPlan *duplicate();
diff --git a/llvm/lib/Transforms/Vectorize/VPlanUtils.cpp b/llvm/lib/Transforms/Vectorize/VPlanUtils.cpp
index 32e4b8872b1df..77aee757476e7 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanUtils.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanUtils.cpp
@@ -32,8 +32,6 @@ bool vputils::onlyScalarValuesUsed(const VPValue *Def) {
 }
 
 VPValue *vputils::getOrCreateVPValueForSCEVExpr(VPlan &Plan, const SCEV *Expr) {
-  if (auto *Expanded = Plan.getSCEVExpansion(Expr))
-    return Expanded;
   VPValue *Expanded = nullptr;
   if (auto *E = dyn_cast<SCEVConstant>(Expr))
     Expanded = Plan.getOrAddLiveIn(E->getValue());
@@ -50,7 +48,6 @@ VPValue *vputils::getOrCreateVPValueForSCEVExpr(VPlan &Plan, const SCEV *Expr) {
       Plan.getEntry()->appendRecipe(Expanded->getDefiningRecipe());
     }
   }
-  Plan.addSCEVExpansion(Expr, Expanded);
   return Expanded;
 }
 

[artagnon]

I actually had this patch initially, but got worried about caching -- on second thought, SCEV internally caches and de-duplicates (maybe add this to the commit message?), so this LGTM, thanks!

[llvm-ci]

LLVM Buildbot has detected a new failure on builder ppc64le-mlir-rhel-clang running on ppc64le-mlir-rhel-test while building llvm at step 6 "test-build-check-mlir-build-only-check-mlir".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/129/builds/32159

Here is the relevant piece of the build log for the reference

Step 6 (test-build-check-mlir-build-only-check-mlir) failure: 1200 seconds without output running [b'ninja', b'check-mlir'], attempting to kill
...
PASS: MLIR-Unit :: IR/./MLIRIRTests/100/130 (3598 of 3609)
PASS: MLIR-Unit :: IR/./MLIRIRTests/0/130 (3599 of 3609)
PASS: MLIR-Unit :: IR/./MLIRIRTests/101/130 (3600 of 3609)
PASS: MLIR-Unit :: IR/./MLIRIRTests/39/130 (3601 of 3609)
PASS: MLIR-Unit :: Interfaces/./MLIRInterfacesTests/12/22 (3602 of 3609)
PASS: MLIR-Unit :: Interfaces/./MLIRInterfacesTests/13/22 (3603 of 3609)
PASS: MLIR-Unit :: IR/./MLIRIRTests/38/130 (3604 of 3609)
PASS: MLIR-Unit :: Interfaces/./MLIRInterfacesTests/11/22 (3605 of 3609)
PASS: MLIR-Unit :: Pass/./MLIRPassTests/10/13 (3606 of 3609)
PASS: MLIR :: mlir-reduce/dce-test.mlir (3607 of 3609)
command timed out: 1200 seconds without output running [b'ninja', b'check-mlir'], attempting to kill
process killed by signal 9
program finished with exit code -1
elapsedTime=3648.366012