commit fea4a48c0baabb4732e6a7fd826755f011e19e0a
author Max Kazantsev <mkazantsev@azul.com> Mon Oct 25 04:36:25 2021
committer Max Kazantsev <mkazantsev@azul.com> Mon Oct 25 05:14:18 2021
tree e94a06b7790b60947e946eb5ac147a84e3aa35f7
parent a8c1d9d63e121f16d49b3f80c76f695dfcbcc142

[SCEV][NFC] API for tracking of SCEV users

This patch introduces API that keeps track of SCEVs users of
another SCEVs, required to handle invalidations of users along
with operands that comes in follow-up patches.

Differential Revision: https://reviews.llvm.org/D112295
Reviewed By: reames

llvm/include/llvm/Analysis/ScalarEvolution.h

diff --git a/llvm/include/llvm/Analysis/ScalarEvolution.h b/llvm/include/llvm/Analysis/ScalarEvolution.h
index ae7f16c..1165981 100644
--- a/llvm/include/llvm/Analysis/ScalarEvolution.h
+++ b/llvm/include/llvm/Analysis/ScalarEvolution.h
@@ -537,6 +537,9 @@
   std::pair<SCEV::NoWrapFlags, bool /*Deduced*/>
   getStrengthenedNoWrapFlagsFromBinOp(const OverflowingBinaryOperator *OBO);
 
+  /// Notify this ScalarEvolution that \p User directly uses SCEVs in \p Ops.
+  void registerUser(const SCEV *User, ArrayRef<const SCEV *> Ops);
+
   /// Return a SCEV expression for the full generality of the specified
   /// expression.
   const SCEV *getSCEV(Value *V);
@@ -1506,6 +1509,9 @@
   /// Compute a BlockDisposition value.
   BlockDisposition computeBlockDisposition(const SCEV *S, const BasicBlock *BB);
 
+  /// Stores all SCEV that use a given SCEV as its direct operand.
+  DenseMap<const SCEV *, SmallPtrSet<const SCEV *, 8> > SCEVUsers;
+
   /// Memoized results from getRange
   DenseMap<const SCEV *, ConstantRange> UnsignedRanges;
 

llvm/lib/Analysis/ScalarEvolution.cpp

diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index 33fe59e..7898438 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -1099,6 +1099,7 @@
         SCEVPtrToIntExpr(ID.Intern(SCEVAllocator), Op, IntPtrTy);
     UniqueSCEVs.InsertNode(S, IP);
     addToLoopUseLists(S);
+    registerUser(S, Op);
     return S;
   }
 
@@ -1219,6 +1220,7 @@
         new (SCEVAllocator) SCEVTruncateExpr(ID.Intern(SCEVAllocator), Op, Ty);
     UniqueSCEVs.InsertNode(S, IP);
     addToLoopUseLists(S);
+    registerUser(S, Op);
     return S;
   }
 
@@ -1273,6 +1275,7 @@
                                                  Op, Ty);
   UniqueSCEVs.InsertNode(S, IP);
   addToLoopUseLists(S);
+  registerUser(S, Op);
   return S;
 }
 
@@ -1602,6 +1605,7 @@
                                                      Op, Ty);
     UniqueSCEVs.InsertNode(S, IP);
     addToLoopUseLists(S);
+    registerUser(S, Op);
     return S;
   }
 
@@ -1871,6 +1875,7 @@
                                                    Op, Ty);
   UniqueSCEVs.InsertNode(S, IP);
   addToLoopUseLists(S);
+  registerUser(S, Op);
   return S;
 }
 
@@ -1910,6 +1915,7 @@
                                                      Op, Ty);
     UniqueSCEVs.InsertNode(S, IP);
     addToLoopUseLists(S);
+    registerUser(S, Op);
     return S;
   }
 
@@ -2107,6 +2113,7 @@
                                                    Op, Ty);
   UniqueSCEVs.InsertNode(S, IP);
   addToLoopUseLists(S);
+  registerUser(S, { Op });
   return S;
 }
 
@@ -2892,6 +2899,7 @@
         SCEVAddExpr(ID.Intern(SCEVAllocator), O, Ops.size());
     UniqueSCEVs.InsertNode(S, IP);
     addToLoopUseLists(S);
+    registerUser(S, Ops);
   }
   S->setNoWrapFlags(Flags);
   return S;
@@ -2915,6 +2923,7 @@
         SCEVAddRecExpr(ID.Intern(SCEVAllocator), O, Ops.size(), L);
     UniqueSCEVs.InsertNode(S, IP);
     addToLoopUseLists(S);
+    registerUser(S, Ops);
   }
   setNoWrapFlags(S, Flags);
   return S;
@@ -2937,6 +2946,7 @@
                                         O, Ops.size());
     UniqueSCEVs.InsertNode(S, IP);
     addToLoopUseLists(S);
+    registerUser(S, Ops);
   }
   S->setNoWrapFlags(Flags);
   return S;
@@ -3446,6 +3456,7 @@
                                              LHS, RHS);
   UniqueSCEVs.InsertNode(S, IP);
   addToLoopUseLists(S);
+  registerUser(S, {LHS, RHS});
   return S;
 }
 
@@ -3840,6 +3851,7 @@
 
   UniqueSCEVs.InsertNode(S, IP);
   addToLoopUseLists(S);
+  registerUser(S, Ops);
   return S;
 }
 
@@ -12325,6 +12337,7 @@
       LoopDispositions(std::move(Arg.LoopDispositions)),
       LoopPropertiesCache(std::move(Arg.LoopPropertiesCache)),
       BlockDispositions(std::move(Arg.BlockDispositions)),
+      SCEVUsers(std::move(Arg.SCEVUsers)),
       UnsignedRanges(std::move(Arg.UnsignedRanges)),
       SignedRanges(std::move(Arg.SignedRanges)),
       UniqueSCEVs(std::move(Arg.UniqueSCEVs)),
@@ -13288,6 +13301,12 @@
                                                      Loop &L)
     : SE(SE), L(L) {}
 
+void ScalarEvolution::registerUser(const SCEV *User,
+                                   ArrayRef<const SCEV *> Ops) {
+  for (auto *Op : Ops)
+    SCEVUsers[Op].insert(User);
+}
+
 const SCEV *PredicatedScalarEvolution::getSCEV(Value *V) {
   const SCEV *Expr = SE.getSCEV(V);
   RewriteEntry &Entry = RewriteMap[Expr];