SCEV: Compress disposition pairs.

Composing DenseMaps and SmallVectors is still somewhat suboptimal,
but this at least halves the size of the vector elements. NFC.

llvm-svn: 228497

1 files changed, 18 insertions, 18 deletions

diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index 510523ec60a..9b9e7dc5eea 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -8000,17 +8000,17 @@ void ScalarEvolution::print(raw_ostream &OS, const Module *) const {
 
 ScalarEvolution::LoopDisposition
 ScalarEvolution::getLoopDisposition(const SCEV *S, const Loop *L) {
-  SmallVector<std::pair<const Loop *, LoopDisposition>, 2> &Values = LoopDispositions[S];
-  for (unsigned u = 0; u < Values.size(); u++) {
-    if (Values[u].first == L)
-      return Values[u].second;
+  auto &Values = LoopDispositions[S];
+  for (auto &V : Values) {
+    if (V.getPointer() == L)
+      return V.getInt();
   }
-  Values.push_back(std::make_pair(L, LoopVariant));
+  Values.emplace_back(L, LoopVariant);
   LoopDisposition D = computeLoopDisposition(S, L);
-  SmallVector<std::pair<const Loop *, LoopDisposition>, 2> &Values2 = LoopDispositions[S];
-  for (unsigned u = Values2.size(); u > 0; u--) {
-    if (Values2[u - 1].first == L) {
-      Values2[u - 1].second = D;
+  auto &Values2 = LoopDispositions[S];
+  for (auto &V : make_range(Values2.rbegin(), Values2.rend())) {
+    if (V.getPointer() == L) {
+      V.setInt(D);
       break;
     }
   }
@@ -8106,17 +8106,17 @@ bool ScalarEvolution::hasComputableLoopEvolution(const SCEV *S, const Loop *L) {
 
 ScalarEvolution::BlockDisposition
 ScalarEvolution::getBlockDisposition(const SCEV *S, const BasicBlock *BB) {
-  SmallVector<std::pair<const BasicBlock *, BlockDisposition>, 2> &Values = BlockDispositions[S];
-  for (unsigned u = 0; u < Values.size(); u++) {
-    if (Values[u].first == BB)
-      return Values[u].second;
+  auto &Values = BlockDispositions[S];
+  for (auto &V : Values) {
+    if (V.getPointer() == BB)
+      return V.getInt();
   }
-  Values.push_back(std::make_pair(BB, DoesNotDominateBlock));
+  Values.emplace_back(BB, DoesNotDominateBlock);
   BlockDisposition D = computeBlockDisposition(S, BB);
-  SmallVector<std::pair<const BasicBlock *, BlockDisposition>, 2> &Values2 = BlockDispositions[S];
-  for (unsigned u = Values2.size(); u > 0; u--) {
-    if (Values2[u - 1].first == BB) {
-      Values2[u - 1].second = D;
+  auto &Values2 = BlockDispositions[S];
+  for (auto &V : make_range(Values2.rbegin(), Values2.rend())) {
+    if (V.getPointer() == BB) {
+      V.setInt(D);
       break;
     }
   }