search for: add16ri

...[(set GR16:$dst, (add GR16:$src1, (mul GR16:$src2, GR16:$src3)))]> } How can i tell the system X=A*B + C == X = B*A + C == X=C+A*B == X=C+B*A by property 'isCommutable'? Is it necessary to do that? *** Another question: Why set isCommutable = 1 in ADD16rr but NOT set in ADD16ri? let isCommutable = 1 in { // X = ADD Y, Z == X = ADD Z, Y def ADD16rr : Pseudo<(outs GR16:$dst), (ins GR16:$src1, GR16:$src2), "add.w\t{$src2, $dst}", [(set GR16:$dst, (add GR16:$src1, GR16:$src2)), (implicit SRW)]>;...

...s it necessary to do that? Most probably you will need to write a special hook to commute this instruction. However, everything depends on your target (e.g. if there is an output register tied to one of the input). > *** Another question: Why set isCommutable = 1 in ADD16rr but NOT set in > ADD16ri? Because all msp430 instructions are two-address, this means that output register is tied to first input. That's why you cannot swap operands for reg-imm operations. -- With best regards, Anton Korobeynikov Faculty of Mathematics and Mechanics, Saint Petersburg State University

...benifit it has if 'isCommuatble=1' in instruction selection, register allocation or other process? Regards 2009/12/7, Anton Korobeynikov <anton at korobeynikov.info>: > > Hello > > > *** Another question: Why set isCommutable = 1 in ADD16rr but NOT set in > > ADD16ri? > Because all msp430 instructions are two-address, this means that > output register is tied to first input. That's why you cannot swap > operands for reg-imm operations. > > -- > With best regards, Anton Korobeynikov > Faculty of Mathematics and Mechanics, Saint Petersbur...

...OV16ri 10 %R12W<def> = SUB16rr %R12W, %R15W<kill>, %SRW<imp-def> %R15W<def> = MOV16rr %R12W<kill> RET %R15W<imp-use,kill> if.end7: 0xa244cb8, LLVM BB @0xa1f09c0, ID#3: Live Ins: %R15W %R15B Predecessors according to CFG: 0xa244c20 (#1) %R15W<def> = ADD16ri %R15W, 18, %SRW<imp-def> RET %R15W<imp-use,kill> return: 0xa244d04, LLVM BB @0xa1efa18, ID#4: Live Ins: %R15W %R15B Predecessors according to CFG: 0xa244bd4 (#0) RET %R15W<imp-use,kill> # End machine code for f(). *** Bad machine code: Live-in physical register is not liv...