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Fix (hopefully the last) issue where LSR is nondeterminstic. When pulling
out CSE's of base expressions it could build a result whose order was nondet. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23698 91177308-0d34-0410-b5e6-96231b3b80d8
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@ -715,6 +715,10 @@ RemoveCommonExpressionsFromUseBases(std::vector<BasedUser> &Uses) {
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// If any subexpressions are used Uses.size() times, they are common.
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std::map<SCEVHandle, unsigned> SubExpressionUseCounts;
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// UniqueSubExprs - Keep track of all of the subexpressions we see in the
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// order we see them.
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std::vector<SCEVHandle> UniqueSubExprs;
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std::vector<SCEVHandle> SubExprs;
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for (unsigned i = 0; i != NumUses; ++i) {
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// If the base is zero (which is common), return zero now, there are no
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@ -725,22 +729,24 @@ RemoveCommonExpressionsFromUseBases(std::vector<BasedUser> &Uses) {
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SeparateSubExprs(SubExprs, Uses[i].Base);
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// Add one to SubExpressionUseCounts for each subexpr present.
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for (unsigned j = 0, e = SubExprs.size(); j != e; ++j)
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SubExpressionUseCounts[SubExprs[j]]++;
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if (++SubExpressionUseCounts[SubExprs[j]] == 1)
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UniqueSubExprs.push_back(SubExprs[j]);
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SubExprs.clear();
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}
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// Now that we know how many times each is used, build Result.
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for (std::map<SCEVHandle, unsigned>::iterator I =
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SubExpressionUseCounts.begin(), E = SubExpressionUseCounts.end();
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I != E; )
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// Now that we know how many times each is used, build Result. Iterate over
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// UniqueSubexprs so that we have a stable ordering.
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for (unsigned i = 0, e = UniqueSubExprs.size(); i != e; ++i) {
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std::map<SCEVHandle, unsigned>::iterator I =
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SubExpressionUseCounts.find(UniqueSubExprs[i]);
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assert(I != SubExpressionUseCounts.end() && "Entry not found?");
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if (I->second == NumUses) { // Found CSE!
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Result = SCEVAddExpr::get(Result, I->first);
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++I;
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} else {
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// Remove non-cse's from SubExpressionUseCounts.
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SubExpressionUseCounts.erase(I++);
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SubExpressionUseCounts.erase(I);
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}
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}
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// If we found no CSE's, return now.
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if (Result == Zero) return Result;
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