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Hi All, My target has some instructions requiring register pairs. I decided to give a try to the PBQP allocator : it is working fine in 99% of the cases, but I am stumbling on the following issue. Instruction 'MPQD' takes 3 register operands inputs, with the constraint that operands 0 and 2 must be consecutive registers. Operand 1 has no particular constraint. It has no output register. So we have something like MPQD R_n, R_x, R_n+1. I have derived from PBQPBuilder to add the MPQD constraint. It happens...

...un 6, 2011, at 7:07 AM, Arnaud Allard de Grandmaison wrote: > Hi All, > > My target has some instructions requiring register pairs. I decided to give a try to the PBQP allocator : it is working fine in 99% of the cases, but I am stumbling on the following issue. > > Instruction ‘MPQD’ takes 3 register operands inputs, with the constraint that operands 0 and 2 must be consecutive registers. Operand 1 has no particular constraint. It has no output register. So we have something like MPQD R_n, R_x, R_n+1. > > I have derived from PBQPBuilder to add the MPQD constraint. >...

Arnaud, another way to look at it, if the description of your register sets includes "pairs", is that your assembly language syntax for MPQD is redundant, operand-2 is the second half of the register-pair in operand-0, so an alternative is to let llvm think this is a two operand instruction (one of them being a pair) rather than a three operand instruction. even if you are not currently defining pairs in your register definiti...

On Jun 6, 2011, at 12:14 PM, Peter Lawrence wrote: > Arnaud, > another way to look at it, if the description of your register sets includes "pairs", > is that your assembly language syntax for MPQD is redundant, operand-2 is the second > half of the register-pair in operand-0, so an alternative is to let llvm think this is a two > operand instruction (one of them being a pair) rather than a three operand instruction. > > even if you are not currently defining pairs in your regis...

...dev at cs.uiuc.edu Subject: Re: [LLVMdev] PBQP & register pairing On Jun 6, 2011, at 12:14 PM, Peter Lawrence wrote: > Arnaud, > another way to look at it, if the description of your register sets includes "pairs", > is that your assembly language syntax for MPQD is redundant, operand-2 is the second > half of the register-pair in operand-0, so an alternative is to let llvm think this is a two > operand instruction (one of them being a pair) rather than a three operand instruction. > > even if you are not currently defining pairs in your regist...

...dev] PBQP & register pairing > > > On Jun 6, 2011, at 12:14 PM, Peter Lawrence wrote: > > > Arnaud, > > another way to look at it, if the description of your > register sets includes "pairs", > > is that your assembly language syntax for MPQD is redundant, operand-2 is > the second > > half of the register-pair in operand-0, so an alternative is to let llvm > think this is a two > > operand instruction (one of them being a pair) rather than a three > operand instruction. > > > > even if you are not curr...

...at cs.uiuc.edu> Subject: Re: [LLVMdev] PBQP & register pairing On Jun 6, 2011, at 12:14 PM, Peter Lawrence wrote: > Arnaud, > another way to look at it, if the description of your register sets includes "pairs", > is that your assembly language syntax for MPQD is redundant, operand-2 is the second > half of the register-pair in operand-0, so an alternative is to let llvm think this is a two > operand instruction (one of them being a pair) rather than a three operand instruction. > > even if you are not currently defining pairs in your regist...