[PATCH] D112516: [SCEV][NFC] Factor out common API for getting unique operands of a SCEV

[Max Kazantsev via Phabricator via llvm-commits]

mkazantsev updated this revision to Diff 383557.
mkazantsev added a comment.
This revision is now accepted and ready to land.

Addressed Nikita's non-determinism concern.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D112516/new/

https://reviews.llvm.org/D112516

Files:
  llvm/lib/Analysis/ScalarEvolution.cpp


Index: llvm/lib/Analysis/ScalarEvolution.cpp
===================================================================
--- llvm/lib/Analysis/ScalarEvolution.cpp
+++ llvm/lib/Analysis/ScalarEvolution.cpp
@@ -6589,6 +6589,26 @@
   return nullptr;
 }
 
+/// Fills \p Ops with unique operands of \p S, if it has operands. If not,
+/// \p Ops remains unmodified.
+static void collectUniqueOps(const SCEV *S,
+                             SmallVectorImpl<const SCEV *> &Ops) {
+  SmallPtrSet<const SCEV *, 4> Unique;
+  auto InsertUnique = [&](const SCEV *S) {
+    if (Unique.insert(S).second)
+      Ops.push_back(S);
+  };
+  if (auto *S2 = dyn_cast<SCEVCastExpr>(S))
+    for (auto *Op : S2->operands())
+      InsertUnique(Op);
+  else if (auto *S2 = dyn_cast<SCEVNAryExpr>(S))
+    for (auto *Op : S2->operands())
+      InsertUnique(Op);
+  else if (auto *S2 = dyn_cast<SCEVUDivExpr>(S))
+    for (auto *Op : S2->operands())
+      InsertUnique(Op);
+}
+
 const Instruction *
 ScalarEvolution::getDefiningScopeBound(ArrayRef<const SCEV *> Ops) {
   // Do a bounded search of the def relation of the requested SCEVs.
@@ -6612,15 +6632,12 @@
     if (auto *DefI = getNonTrivialDefiningScopeBound(S)) {
       if (!Bound || DT.dominates(Bound, DefI))
         Bound = DefI;
-    } else if (auto *S2 = dyn_cast<SCEVCastExpr>(S))
-      for (auto *Op : S2->operands())
-        pushOp(Op);
-    else if (auto *S2 = dyn_cast<SCEVNAryExpr>(S))
-      for (auto *Op : S2->operands())
-        pushOp(Op);
-    else if (auto *S2 = dyn_cast<SCEVUDivExpr>(S))
-      for (auto *Op : S2->operands())
+    } else {
+      SmallVector<const SCEV *, 4> Ops;
+      collectUniqueOps(S, Ops);
+      for (auto *Op : Ops)
         pushOp(Op);
+    }
   }
   return Bound ? Bound : &*F.getEntryBlock().begin();
 }
@@ -12908,15 +12925,8 @@
 
   // Verify intergity of SCEV users.
   for (const auto &S : UniqueSCEVs) {
-    SmallPtrSet<const SCEV *, 4> Ops;
-    if (const auto *NS = dyn_cast<SCEVNAryExpr>(&S))
-      Ops.insert(NS->op_begin(), NS->op_end());
-    else if (const auto *CS = dyn_cast<SCEVCastExpr>(&S))
-      Ops.insert(CS->getOperand());
-    else if (const auto *DS = dyn_cast<SCEVUDivExpr>(&S)) {
-      Ops.insert(DS->getLHS());
-      Ops.insert(DS->getRHS());
-    }
+    SmallVector<const SCEV *, 4> Ops;
+    collectUniqueOps(&S, Ops);
     for (const auto *Op : Ops) {
       // We do not store dependencies of constants.
       if (isa<SCEVConstant>(Op))


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D112516.383557.patch
Type: text/x-patch
Size: 2458 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20211030/111aa58f/attachment.bin>