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| author | Akira Hatanaka <ahatanak@gmail.com> | 2011-06-07 18:00:14 +0000 |
|---|---|---|
| committer | Akira Hatanaka <ahatanak@gmail.com> | 2011-06-07 18:00:14 +0000 |
| commit | 6cd4b4e657d757203d84bdbadb3fcad55bcdbc3c (patch) | |
| tree | 5ab2d49b7c9fb7a229801b462e19e1fe0d7177e7 | |
| parent | be234dabf4c58a40c2b063f2e3a8c6cb0ab73a3b (diff) | |
Add comments for wrapper node patterns in MipsInstrInfo.td.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132717 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/Target/Mips/MipsInstrInfo.td | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/lib/Target/Mips/MipsInstrInfo.td b/lib/Target/Mips/MipsInstrInfo.td index b32ae6faf8..329a002667 100644 --- a/lib/Target/Mips/MipsInstrInfo.td +++ b/lib/Target/Mips/MipsInstrInfo.td @@ -87,7 +87,16 @@ def MipsDivRem : SDNode<"MipsISD::DivRem", SDT_MipsDivRem, def MipsDivRemU : SDNode<"MipsISD::DivRemU", SDT_MipsDivRem, [SDNPOutGlue]>; -// wrapper node +// Target constant nodes that are not part of any isel patterns and remain +// unchanged can cause instructions with illegal operands to be emitted. +// Wrapper node patterns give the instruction selector a chance to replace +// target constant nodes that would otherwise remain unchanged with ADDiu +// nodes. Without these wrapper node patterns, the following conditional move +// instrucion is emitted when function cmov2 in test/CodeGen/Mips/cmov.ll is +// compiled: +// movn %got(d)($gp), %got(c)($gp), $4 +// This instruction is illegal since movn can take only register operands. + def MipsWrapperPIC : SDNode<"MipsISD::WrapperPIC", SDTIntUnaryOp>; //===----------------------------------------------------------------------===// |