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llvm-svn: 6415
This commit is contained in:
Chris Lattner 2003-05-29 20:26:30 +00:00
parent 01246aa56d
commit 6c81ebc97d
1 changed files with 11 additions and 0 deletions
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11
llvm/lib/Transforms/Scalar/PRE.cpp
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@ -307,6 +307,17 @@ bool PRE::ProcessExpression(Instruction *Expr) {
std::vector<Value*> Values; std::vector<Value*> Values;
VN->getEqualNumberNodes(Expr, Values); VN->getEqualNumberNodes(Expr, Values);
#if 0
// FIXME: This should handle PHI nodes correctly. To do this, we need to
// consider expressions of the following form equivalent to this set of
// expressions:
//
// If an operand is a PHI node, add any occurances of the expression with the
// PHI operand replaced with the PHI node operands. This is only valid if the
// PHI operand occurances exist in blocks post-dominated by the incoming edge
// of the PHI node.
#endif
// We have to be careful to handle expression definitions which dominated by // We have to be careful to handle expression definitions which dominated by
// other expressions. These can be directly eliminated in favor of their // other expressions. These can be directly eliminated in favor of their
// dominating value. Keep track of which blocks contain definitions (the key) // dominating value. Keep track of which blocks contain definitions (the key)