Index: llvm/trunk/include/llvm/Analysis/VectorUtils.h
===================================================================
--- llvm/trunk/include/llvm/Analysis/VectorUtils.h
+++ llvm/trunk/include/llvm/Analysis/VectorUtils.h
@@ -15,6 +15,7 @@
 #define LLVM_TRANSFORMS_UTILS_VECTORUTILS_H
 
 #include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/MapVector.h"
 #include "llvm/Analysis/TargetLibraryInfo.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/Intrinsics.h"
@@ -121,7 +122,7 @@
 ///
 /// If the optional TargetTransformInfo is provided, this function tries harder
 /// to do less work by only looking at illegal types.
-DenseMap<Instruction*, uint64_t>
+MapVector<Instruction*, uint64_t>
 computeMinimumValueSizes(ArrayRef<BasicBlock*> Blocks,
                          DemandedBits &DB,
                          const TargetTransformInfo *TTI=nullptr);
Index: llvm/trunk/lib/Analysis/VectorUtils.cpp
===================================================================
--- llvm/trunk/lib/Analysis/VectorUtils.cpp
+++ llvm/trunk/lib/Analysis/VectorUtils.cpp
@@ -438,7 +438,7 @@
   return InsertEltInst->getOperand(1);
 }
 
-DenseMap<Instruction *, uint64_t>
+MapVector<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;
+  MapVector<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 MapVector<Instruction *, uint64_t>();
 
     uint64_t V = DB.getDemandedBits(I).getZExtValue();
     DBits[Leader] |= V;
Index: llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp
===================================================================
--- llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ llvm/trunk/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) {
+                 MapVector<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;
+  MapVector<Instruction*,uint64_t> MinBWs;
   LoopVectorizationLegality *Legal;
 
   // Record whether runtime check is added.
@@ -1505,7 +1505,7 @@
   /// 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;
+  MapVector<Instruction*,uint64_t> MinBWs;
 
   /// The loop that we evaluate.
   Loop *TheLoop;
Index: llvm/trunk/test/Transforms/LoopVectorize/AArch64/deterministic-type-shrinkage.ll
===================================================================
--- llvm/trunk/test/Transforms/LoopVectorize/AArch64/deterministic-type-shrinkage.ll
+++ llvm/trunk/test/Transforms/LoopVectorize/AArch64/deterministic-type-shrinkage.ll
@@ -0,0 +1,54 @@
+; RUN: opt -S < %s -loop-vectorize -instcombine 2>&1 | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-i128:128-n32:64-S128"
+target triple = "aarch64"
+
+;; See https://llvm.org/bugs/show_bug.cgi?id=25490
+;; Due to the data structures used, the LLVM IR was not determinisic.
+;; This test comes from the PR.
+
+;; CHECK-LABEL: @test(
+; CHECK: load <16 x i8>
+; CHECK-NEXT: getelementptr
+; CHECK-NEXT: bitcast
+; CHECK-NEXT: load <16 x i8>
+; CHECK-NEXT: zext <16 x i8>
+; CHECK-NEXT: zext <16 x i8>
+define void @test(i32 %n, i8* nocapture %a, i8* nocapture %b, i8* nocapture readonly %c) {
+entry:
+  %cmp.28 = icmp eq i32 %n, 0
+  br i1 %cmp.28, label %for.cond.cleanup, label %for.body.preheader
+
+for.body.preheader:                               ; preds = %entry
+  br label %for.body
+
+for.cond.cleanup.loopexit:                        ; preds = %for.body
+  br label %for.cond.cleanup
+
+for.cond.cleanup:                                 ; preds = %for.cond.cleanup.loopexit, %entry
+  ret void
+
+for.body:                                         ; preds = %for.body.preheader, %for.body
+  %indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %for.body.preheader ]
+  %arrayidx = getelementptr inbounds i8, i8* %c, i64 %indvars.iv
+  %0 = load i8, i8* %arrayidx, align 1
+  %conv = zext i8 %0 to i32
+  %arrayidx2 = getelementptr inbounds i8, i8* %a, i64 %indvars.iv
+  %1 = load i8, i8* %arrayidx2, align 1
+  %conv3 = zext i8 %1 to i32
+  %mul = mul nuw nsw i32 %conv3, %conv
+  %shr.26 = lshr i32 %mul, 8
+  %conv4 = trunc i32 %shr.26 to i8
+  store i8 %conv4, i8* %arrayidx2, align 1
+  %arrayidx8 = getelementptr inbounds i8, i8* %b, i64 %indvars.iv
+  %2 = load i8, i8* %arrayidx8, align 1
+  %conv9 = zext i8 %2 to i32
+  %mul10 = mul nuw nsw i32 %conv9, %conv
+  %shr11.27 = lshr i32 %mul10, 8
+  %conv12 = trunc i32 %shr11.27 to i8
+  store i8 %conv12, i8* %arrayidx8, align 1
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+  %lftr.wideiv = trunc i64 %indvars.iv.next to i32
+  %exitcond = icmp eq i32 %lftr.wideiv, %n
+  br i1 %exitcond, label %for.cond.cleanup.loopexit, label %for.body
+}