forked from OSchip/llvm-project
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@ -7,25 +7,7 @@
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//
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//===----------------------------------------------------------------------===//
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//
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// This pass promotes "by reference" arguments to be "by value" arguments. In
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// practice, this means looking for internal functions that have pointer
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// arguments. If it can prove, through the use of alias analysis, that an
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// argument is *only* loaded, then it can pass the value into the function
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// instead of the address of the value. This can cause recursive simplification
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// of code and lead to the elimination of allocas (especially in C++ template
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// code like the STL).
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//
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// This pass also handles aggregate arguments that are passed into a function,
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// scalarizing them if the elements of the aggregate are only loaded. Note that
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// it refuses to scalarize aggregates which would require passing in more than
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// three operands to the function, because passing thousands of operands for a
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// large array or structure is unprofitable!
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//
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// Note that this transformation could also be done for arguments that are only
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// stored to (returning the value instead), but does not currently. This case
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// would be best handled when and if LLVM begins supporting multiple return
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// values from functions.
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//
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// TODO : Describe this pass.
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "sretpromotion"
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