[llvm-commits] [llvm] r159451 - /llvm/trunk/lib/Transforms/Scalar/Reassociate.cpp
Duncan Sands
baldrick at free.fr
Fri Jun 29 12:03:05 PDT 2012
Author: baldrick
Date: Fri Jun 29 14:03:05 2012
New Revision: 159451
URL: http://llvm.org/viewvc/llvm-project?rev=159451&view=rev
Log:
Rework this to clarify where the removal of nodes from the queue is
really happening. No intended functionality change.
Modified:
llvm/trunk/lib/Transforms/Scalar/Reassociate.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/Reassociate.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/Reassociate.cpp?rev=159451&r1=159450&r2=159451&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/Reassociate.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/Reassociate.cpp Fri Jun 29 14:03:05 2012
@@ -667,15 +667,13 @@
/// the new expression into.
SmallVector<BinaryOperator*, 8> NodesToRewrite;
unsigned Opcode = I->getOpcode();
- NodesToRewrite.push_back(I);
+ BinaryOperator *Op = I;
// ExpressionChanged - Non-null if the rewritten expression differs from the
// original in some non-trivial way, requiring the clearing of optional flags.
// Flags are cleared from the operator in ExpressionChanged up to I inclusive.
BinaryOperator *ExpressionChanged = 0;
for (unsigned i = 0; ; ++i) {
- BinaryOperator *Op = NodesToRewrite.pop_back_val();
-
// The last operation (which comes earliest in the IR) is special as both
// operands will come from Ops, rather than just one with the other being
// a subexpression.
@@ -746,7 +744,7 @@
// from the original expression then just rewrite the rest of the expression
// into it.
if (BinaryOperator *BO = isReassociableOp(Op->getOperand(0), Opcode)) {
- NodesToRewrite.push_back(BO);
+ Op = BO;
continue;
}
@@ -757,19 +755,22 @@
// hard (finding the mimimal number of multiplications needed to realize a
// multiplication expression is NP-complete). Whatever the reason, smart or
// stupid, create a new node if there are none left.
+ BinaryOperator *NewOp;
if (NodesToRewrite.empty()) {
Constant *Undef = UndefValue::get(I->getType());
- BinaryOperator *N = BinaryOperator::Create(Instruction::BinaryOps(Opcode),
- Undef, Undef, "", I);
- NodesToRewrite.push_back(N);
+ NewOp = BinaryOperator::Create(Instruction::BinaryOps(Opcode),
+ Undef, Undef, "", I);
+ } else {
+ NewOp = NodesToRewrite.pop_back_val();
}
DEBUG(dbgs() << "RA: " << *Op << '\n');
- Op->setOperand(0, NodesToRewrite.back());
+ Op->setOperand(0, NewOp);
DEBUG(dbgs() << "TO: " << *Op << '\n');
ExpressionChanged = Op;
MadeChange = true;
++NumChanged;
+ Op = NewOp;
}
// If the expression changed non-trivially then clear out all subclass data
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