Changes in directory llvm/lib/CodeGen/SelectionDAG:
DAGCombiner.cpp updated: 1.209 -> 1.210 --- Log message: Eliminate more token factors by taking advantage of transitivity: if TF depends on A and B, and A depends on B, TF just needs to depend on A. With Jim's alias-analysis stuff enabled, this compiles the testcase in PR892: http://llvm.org/PR892 into: __Z4test3Val: subl $44, %esp call L__Z3foov$stub movl %edx, 28(%esp) movl %eax, 32(%esp) movl %eax, 24(%esp) movl %edx, 36(%esp) movl 52(%esp), %ecx movl %ecx, 4(%esp) movl %eax, 8(%esp) movl %edx, 12(%esp) movl 48(%esp), %eax movl %eax, (%esp) call L__Z3bar3ValS_$stub addl $44, %esp ret instead of: __Z4test3Val: subl $44, %esp call L__Z3foov$stub movl %eax, 24(%esp) movl %edx, 28(%esp) movl 24(%esp), %eax movl %eax, 32(%esp) movl 28(%esp), %eax movl %eax, 36(%esp) movl 32(%esp), %eax movl 36(%esp), %ecx movl 52(%esp), %edx movl %edx, 4(%esp) movl %eax, 8(%esp) movl %ecx, 12(%esp) movl 48(%esp), %eax movl %eax, (%esp) call L__Z3bar3ValS_$stub addl $44, %esp ret --- Diffs of the changes: (+25 -0) DAGCombiner.cpp | 25 +++++++++++++++++++++++++ 1 files changed, 25 insertions(+) Index: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp diff -u llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:1.209 llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:1.210 --- llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:1.209 Sat Oct 7 18:37:56 2006 +++ llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Sun Oct 8 17:57:01 2006 @@ -518,7 +518,32 @@ return SDOperand(); } +/// getInputChainForNode - Given a node, return its input chain if it has one, +/// otherwise return a null sd operand. +static SDOperand getInputChainForNode(SDNode *N) { + if (unsigned NumOps = N->getNumOperands()) { + if (N->getOperand(0).getValueType() == MVT::Other) + return N->getOperand(0); + else if (N->getOperand(NumOps-1).getValueType() == MVT::Other) + return N->getOperand(NumOps-1); + for (unsigned i = 1; i < NumOps-1; ++i) + if (N->getOperand(i).getValueType() == MVT::Other) + return N->getOperand(i); + } + return SDOperand(0, 0); +} + SDOperand DAGCombiner::visitTokenFactor(SDNode *N) { + // If N has two operands, where one has an input chain equal to the other, + // the 'other' chain is redundant. + if (N->getNumOperands() == 2) { + if (getInputChainForNode(N->getOperand(0).Val) == N->getOperand(1)) + return N->getOperand(0); + if (getInputChainForNode(N->getOperand(1).Val) == N->getOperand(0)) + return N->getOperand(1); + } + + SmallVector<SDNode *, 8> TFs; // List of token factors to visit. SmallVector<SDOperand, 8> Ops; // Ops for replacing token factor. bool Changed = false; // If we should replace this token factor. _______________________________________________ llvm-commits mailing list llvm-commits@cs.uiuc.edu http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
