From 5ec9c58f1394e1232972604d765238594d48fce1 Mon Sep 17 00:00:00 2001
From: David Majnemer <david.majnemer@gmail.com>
Date: Mon, 15 Aug 2016 00:13:04 +0000
Subject: [ScopedNoAliasAA] Remove an unneccesary set

We are trying to prove that one group of operands is a subset of
another.  We did this by populating two Sets and determining that every
element within one was inside the other.

However, this is unnecessary.  We can simply construct a single set and
test if each operand is within it.

llvm-svn: 278641
---
 llvm/lib/Analysis/ScopedNoAliasAA.cpp | 33 +++++++++++++--------------------
 1 file changed, 13 insertions(+), 20 deletions(-)

(limited to 'llvm/lib/Analysis/ScopedNoAliasAA.cpp')

diff --git a/llvm/lib/Analysis/ScopedNoAliasAA.cpp b/llvm/lib/Analysis/ScopedNoAliasAA.cpp
index 1c4d0fa94bf..b631faddbeb 100644
--- a/llvm/lib/Analysis/ScopedNoAliasAA.cpp
+++ b/llvm/lib/Analysis/ScopedNoAliasAA.cpp
@@ -127,15 +127,6 @@ ModRefInfo ScopedNoAliasAAResult::getModRefInfo(ImmutableCallSite CS1,
   return AAResultBase::getModRefInfo(CS1, CS2);
 }
 
-void ScopedNoAliasAAResult::collectMDInDomain(
-    const MDNode *List, const MDNode *Domain,
-    SmallPtrSetImpl<const MDNode *> &Nodes) const {
-  for (const MDOperand &MDOp : List->operands())
-    if (const MDNode *MD = dyn_cast<MDNode>(MDOp))
-      if (AliasScopeNode(MD).getDomain() == Domain)
-        Nodes.insert(MD);
-}
-
 bool ScopedNoAliasAAResult::mayAliasInScopes(const MDNode *Scopes,
                                              const MDNode *NoAlias) const {
   if (!Scopes || !NoAlias)
@@ -151,19 +142,21 @@ bool ScopedNoAliasAAResult::mayAliasInScopes(const MDNode *Scopes,
   // We alias unless, for some domain, the set of noalias scopes in that domain
   // is a superset of the set of alias scopes in that domain.
   for (const MDNode *Domain : Domains) {
-    SmallPtrSet<const MDNode *, 16> NANodes, ScopeNodes;
-    collectMDInDomain(NoAlias, Domain, NANodes);
-    collectMDInDomain(Scopes, Domain, ScopeNodes);
-    if (!ScopeNodes.size())
-      continue;
+    SmallPtrSet<const MDNode *, 16> NANodes;
+    for (const MDOperand &MDOp : NoAlias->operands())
+      if (const MDNode *MD = dyn_cast<MDNode>(MDOp))
+        if (AliasScopeNode(MD).getDomain() == Domain)
+          NANodes.insert(MD);
 
-    // To not alias, all of the nodes in ScopeNodes must be in NANodes.
+    // To not alias, all of the nodes in Scopes must be in NANodes.
     bool FoundAll = true;
-    for (const MDNode *SMD : ScopeNodes)
-      if (!NANodes.count(SMD)) {
-        FoundAll = false;
-        break;
-      }
+    for (const MDOperand &MDOp : Scopes->operands())
+      if (const MDNode *SMD = dyn_cast<MDNode>(MDOp))
+        if (AliasScopeNode(SMD).getDomain() == Domain)
+          if (!NANodes.count(SMD)) {
+            FoundAll = false;
+            break;
+          }
 
     if (FoundAll)
       return false;
-- 
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