Re: Maximum Register Pressure?

Sid Touati <>
14 Mar 2006 00:50:18 -0500

          From comp.compilers

Related articles
Maximum Register Pressure? (2006-03-12)
Re: Maximum Register Pressure? (Sid Touati) (2006-03-14)
Re: Maximum Register Pressure? (Sid Touati) (2006-03-14)
| List of all articles for this month |

From: Sid Touati <>
Newsgroups: comp.compilers
Date: 14 Mar 2006 00:50:18 -0500
Organization: I.N.R.I.A Rocquencourt
References: 06-03-039
Keywords: registers
Posted-Date: 14 Mar 2006 00:50:18 EST a écrit :
> I have a question. Does an optimal schedule of a basic block also
> gives maximum register pressure for that basic block?
> Regards
> Abid


here is a DAG represented with data dependences :
a -> b : flow arc latency = 20
c -> d : flow arc latency = 1
e -> f : flow arc latency = 1

A time-optimal schedule is of latency 20 (assuming enough resources).
Assuming no exit values, ie. the operations b d f do not write into
registers, you can use only two registers in a time-optimal schedule
(schedule the whains a->d and e-> in serial), while the maximal register
pressure is 3 registers (a c e simultaneously alive)


Post a followup to this message

Return to the comp.compilers page.
Search the comp.compilers archives again.