diff options
Diffstat (limited to 'lib/Target/Mips/AsmParser/MipsAsmParser.cpp')
-rw-r--r-- | lib/Target/Mips/AsmParser/MipsAsmParser.cpp | 33 |
1 files changed, 29 insertions, 4 deletions
diff --git a/lib/Target/Mips/AsmParser/MipsAsmParser.cpp b/lib/Target/Mips/AsmParser/MipsAsmParser.cpp index 4a226a9f9d..dd2b857789 100644 --- a/lib/Target/Mips/AsmParser/MipsAsmParser.cpp +++ b/lib/Target/Mips/AsmParser/MipsAsmParser.cpp @@ -1144,10 +1144,35 @@ void MipsAsmParser::expandMemInst(MCInst &Inst, SMLoc IDLoc, ExprOffset = Inst.getOperand(2).getExpr(); // All instructions will have the same location. TempInst.setLoc(IDLoc); - // 1st instruction in expansion is LUi. For load instruction we can use - // the dst register as a temporary if base and dst are different, - // but for stores we must use $at. - if (isLoad && (BaseRegNum != RegOpNum)) + // These are some of the types of expansions we perform here: + // 1) lw $8, sym => lui $8, %hi(sym) + // lw $8, %lo(sym)($8) + // 2) lw $8, offset($9) => lui $8, %hi(offset) + // add $8, $8, $9 + // lw $8, %lo(offset)($9) + // 3) lw $8, offset($8) => lui $at, %hi(offset) + // add $at, $at, $8 + // lw $8, %lo(offset)($at) + // 4) sw $8, sym => lui $at, %hi(sym) + // sw $8, %lo(sym)($at) + // 5) sw $8, offset($8) => lui $at, %hi(offset) + // add $at, $at, $8 + // sw $8, %lo(offset)($at) + // 6) ldc1 $f0, sym => lui $at, %hi(sym) + // ldc1 $f0, %lo(sym)($at) + // + // For load instructions we can use the destination register as a temporary + // if base and dst are different (examples 1 and 2) and if the base register + // is general purpose otherwise we must use $at (example 6) and error if it's + // not available. For stores we must use $at (examples 4 and 5) because we + // must not clobber the source register setting up the offset. + const MCInstrDesc &Desc = getInstDesc(Inst.getOpcode()); + int16_t RegClassOp0 = Desc.OpInfo[0].RegClass; + unsigned RegClassIDOp0 = + getContext().getRegisterInfo()->getRegClass(RegClassOp0).getID(); + bool IsGPR = (RegClassIDOp0 == Mips::GPR32RegClassID) || + (RegClassIDOp0 == Mips::GPR64RegClassID); + if (isLoad && IsGPR && (BaseRegNum != RegOpNum)) TmpRegNum = RegOpNum; else { int AT = getATReg(IDLoc); |