* Phase ordering in compiler
@ 2012-10-22 9:51 vikram1729
2012-10-22 18:14 ` Ian Lance Taylor
0 siblings, 1 reply; 4+ messages in thread
From: vikram1729 @ 2012-10-22 9:51 UTC (permalink / raw)
To: gcc-help
Dear Sir,
I want to understand the phase-ordering problem in compilers. My basic
doubt is what is the difference between the pass and phase in compilers? As
for as I know, Pass something that scans to through the input code snippet
and does some transformation to it and whereas phases in the classicle
compiler are main components/modules which are Lexical Analysis, Parsing,
semantic analysis, IL code Generation, Code Optimization and code
Generation.
When it comes to phase-ordering in compilers is it actually pass ordering or
phase-ordering?
How the user can handle/alter phase-ordering in GCC?
Is it only through changing the order of the optimization options fed to the
compiler or
by tweaking the pass_manager?
Will there be any impact of repeating optimization options or reordering the
optimization options in GCC?
Thanks in Advance,
VSP
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* Re: Phase ordering in compiler
2012-10-22 9:51 Phase ordering in compiler vikram1729
@ 2012-10-22 18:14 ` Ian Lance Taylor
2012-10-25 11:50 ` SANKAR
0 siblings, 1 reply; 4+ messages in thread
From: Ian Lance Taylor @ 2012-10-22 18:14 UTC (permalink / raw)
To: vikram1729; +Cc: gcc-help
On Sun, Oct 21, 2012 at 11:47 PM, vikram1729 <vsp1729@gmail.com> wrote:
> Dear Sir,
> I want to understand the phase-ordering problem in compilers. My basic
> doubt is what is the difference between the pass and phase in compilers?
There is no significant difference. One might think of a phase a
group of passes. Still, it would be reasonable to describe the
phase-ordering problem as a pass-ordering problem.
> How the user can handle/alter phase-ordering in GCC?
You can edit the source code (gcc/passes.c) or you could write a
plugin but there is no way to change the ordering from the command
line.
> Will there be any impact of repeating optimization options or reordering the
> optimization options in GCC?
Yes.
Ian
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Phase ordering in compiler
2012-10-22 18:14 ` Ian Lance Taylor
@ 2012-10-25 11:50 ` SANKAR
2012-10-25 21:51 ` Andrew Haley
0 siblings, 1 reply; 4+ messages in thread
From: SANKAR @ 2012-10-25 11:50 UTC (permalink / raw)
To: gcc-help
When there is an impact of repeating optimisation options or reordering the
optimisation options in GCC, is this pass ordering enabled through command
line?
Sankar
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* Re: Phase ordering in compiler
2012-10-25 11:50 ` SANKAR
@ 2012-10-25 21:51 ` Andrew Haley
0 siblings, 0 replies; 4+ messages in thread
From: Andrew Haley @ 2012-10-25 21:51 UTC (permalink / raw)
To: SANKAR; +Cc: gcc-help
On 10/23/2012 06:21 AM, SANKAR wrote:
> When there is an impact of repeating optimisation options or reordering the
> optimisation options in GCC, is this pass ordering enabled through command
> line?
Not usually, because passes often rely on changes made before them.
Sometimes a pass will work if reordered or duplicated, sometimes not.
Andrew.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2012-10-22 9:51 Phase ordering in compiler vikram1729
2012-10-22 18:14 ` Ian Lance Taylor
2012-10-25 11:50 ` SANKAR
2012-10-25 21:51 ` Andrew Haley
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