[PATCH] D14981: [LoopVectorize] Use std::map rather than DenseMap for MinBWs.

[Charlie Turner via llvm-commits]

chatur01 created this revision.
chatur01 added reviewers: jmolloy, mcrosier.
chatur01 added a subscriber: llvm-commits.
chatur01 set the repository for this revision to rL LLVM.

The order in which instructions are truncated in `truncateToMinimalBitwidths`
effects code generation. Switch to an ordered map implementation, since the
iteration order over a DenseMap is not defined.
    
This code is not hot, so the difference in container performance isn't
interesting.
    
Fixes PR25490.

Repository:
  rL LLVM

http://reviews.llvm.org/D14981

Files:
  include/llvm/Analysis/VectorUtils.h
  lib/Analysis/VectorUtils.cpp
  lib/Transforms/Vectorize/LoopVectorize.cpp

Index: lib/Transforms/Vectorize/LoopVectorize.cpp
===================================================================
--- lib/Transforms/Vectorize/LoopVectorize.cpp
+++ lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -325,7 +325,7 @@
   // can be validly truncated to. The cost model has assumed this truncation
   // will happen when vectorizing.
   void vectorize(LoopVectorizationLegality *L,
-                 DenseMap<Instruction*,uint64_t> MinimumBitWidths) {
+                 std::map<Instruction*,uint64_t> MinimumBitWidths) {
     MinBWs = MinimumBitWidths;
     Legal = L;
     // Create a new empty loop. Unlink the old loop and connect the new one.
@@ -546,7 +546,7 @@
   /// Map of scalar integer values to the smallest bitwidth they can be legally
   /// represented as. The vector equivalents of these values should be truncated
   /// to this type.
-  DenseMap<Instruction*,uint64_t> MinBWs;
+  std::map<Instruction*,uint64_t> MinBWs;
   LoopVectorizationLegality *Legal;
 
   // Record whether runtime check is added.
@@ -1501,7 +1501,7 @@
   /// Map of scalar integer values to the smallest bitwidth they can be legally
   /// represented as. The vector equivalents of these values should be truncated
   /// to this type.
-  DenseMap<Instruction*,uint64_t> MinBWs;
+  std::map<Instruction*,uint64_t> MinBWs;
 
   /// The loop that we evaluate.
   Loop *TheLoop;
Index: lib/Analysis/VectorUtils.cpp
===================================================================
--- lib/Analysis/VectorUtils.cpp
+++ lib/Analysis/VectorUtils.cpp
@@ -438,7 +438,7 @@
   return InsertEltInst->getOperand(1);
 }
 
-DenseMap<Instruction *, uint64_t>
+std::map<Instruction *, uint64_t>
 llvm::computeMinimumValueSizes(ArrayRef<BasicBlock *> Blocks, DemandedBits &DB,
                                const TargetTransformInfo *TTI) {
 
@@ -451,7 +451,7 @@
   SmallPtrSet<Value *, 16> Visited;
   DenseMap<Value *, uint64_t> DBits;
   SmallPtrSet<Instruction *, 4> InstructionSet;
-  DenseMap<Instruction *, uint64_t> MinBWs;
+  std::map<Instruction *, uint64_t> MinBWs;
 
   // Determine the roots. We work bottom-up, from truncs or icmps.
   bool SeenExtFromIllegalType = false;
@@ -497,7 +497,7 @@
     // If we encounter a type that is larger than 64 bits, we can't represent
     // it so bail out.
     if (DB.getDemandedBits(I).getBitWidth() > 64)
-      return DenseMap<Instruction *, uint64_t>();
+      return std::map<Instruction *, uint64_t>();
 
     uint64_t V = DB.getDemandedBits(I).getZExtValue();
     DBits[Leader] |= V;
Index: include/llvm/Analysis/VectorUtils.h
===================================================================
--- include/llvm/Analysis/VectorUtils.h
+++ include/llvm/Analysis/VectorUtils.h
@@ -121,7 +121,7 @@
 ///
 /// If the optional TargetTransformInfo is provided, this function tries harder
 /// to do less work by only looking at illegal types.
-DenseMap<Instruction*, uint64_t>
+std::map<Instruction*, uint64_t>
 computeMinimumValueSizes(ArrayRef<BasicBlock*> Blocks,
                          DemandedBits &DB,
                          const TargetTransformInfo *TTI=nullptr);


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