[llvm-commits] [llvm] r44300 - in /llvm/trunk: include/llvm/Target/TargetLowering.h lib/CodeGen/SelectionDAG/LegalizeDAG.cpp lib/CodeGen/SelectionDAG/LegalizeDAGTypes.cpp lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp lib/Target/ARM/ARMISelLowering.cpp lib/Target/ARM/ARMISelLowering.h lib/Target/X86/X86ISelLowering.cpp lib/Target/X86/X86ISelLowering.h

[Duncan Sands]

Hi Chris,

>  /// RemapNode - If the specified value was already legalized to another value,
>  /// replace it by that value.
>  void DAGTypeLegalizer::RemapNode(SDOperand &N) {
> -  DenseMap<SDOperand, SDOperand>::iterator I = ReplacedNodes.find(N);
> -  if (I != ReplacedNodes.end()) {
> -    RemapNode(I->second);
> +  for (DenseMap<SDOperand, SDOperand>::iterator I = ReplacedNodes.find(N);
> +       I != ReplacedNodes.end(); I = ReplacedNodes.find(N))
>      N = I->second;
> -  }
>  }

in the original version this updated the map too (or at least it was supposed
to).  For example, suppose we remap N and the map contained:
	N -> A
	A -> B
	B -> C
then afterwards we would get N = C, but also the map would be modified to:
	N -> C
	A -> C
	B -> C
This was supposed to speed up later lookups.

> +    if (SDNode *P = TLI.ExpandOperationResult(N, DAG)) {
> +      // Everything that once used N now uses P.  P had better not require
> +      // custom expansion.

How about an assertion that it doesn't require custom expansion?

Ciao,

Duncan.