diff options
| -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>; //===----------------------------------------------------------------------===// |