[PATCH] D32943: [SCEV] Use move semantics in ScalarEvolution::setRange

[Craig Topper via Phabricator via llvm-commits]

craig.topper created this revision.

This makes setRange take ConstantRange by value since most callers were passing an unnamed temporary ConstantRange. We can then move that ConstantRange into the DenseMap caches. For the callers that weren't passing a temporary, I've added std::move to to the local variable being passed.


https://reviews.llvm.org/D32943

Files:
  include/llvm/Analysis/ScalarEvolution.h
  lib/Analysis/ScalarEvolution.cpp


Index: lib/Analysis/ScalarEvolution.cpp
===================================================================
--- lib/Analysis/ScalarEvolution.cpp
+++ lib/Analysis/ScalarEvolution.cpp
@@ -4800,7 +4800,7 @@
       }
     }
 
-    return setRange(AddRec, SignHint, ConservativeResult);
+    return setRange(AddRec, SignHint, std::move(ConservativeResult));
   }
 
   if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) {
@@ -4831,10 +4831,10 @@
                           APInt::getSignedMaxValue(BitWidth).ashr(NS - 1) + 1));
     }
 
-    return setRange(U, SignHint, ConservativeResult);
+    return setRange(U, SignHint, std::move(ConservativeResult));
   }
 
-  return setRange(S, SignHint, ConservativeResult);
+  return setRange(S, SignHint, std::move(ConservativeResult));
 }
 
 // Given a StartRange, Step and MaxBECount for an expression compute a range of
Index: include/llvm/Analysis/ScalarEvolution.h
===================================================================
--- include/llvm/Analysis/ScalarEvolution.h
+++ include/llvm/Analysis/ScalarEvolution.h
@@ -782,13 +782,13 @@
 
   /// Set the memoized range for the given SCEV.
   const ConstantRange &setRange(const SCEV *S, RangeSignHint Hint,
-                                const ConstantRange &CR) {
+                                ConstantRange CR) {
     DenseMap<const SCEV *, ConstantRange> &Cache =
         Hint == HINT_RANGE_UNSIGNED ? UnsignedRanges : SignedRanges;
 
-    auto Pair = Cache.insert({S, CR});
+    auto Pair = Cache.try_emplace(S, std::move(CR));
     if (!Pair.second)
-      Pair.first->second = CR;
+      Pair.first->second = std::move(CR);
     return Pair.first->second;
   }
 


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