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RE: PATCH : collecting more info in the init_alias_analysis pass
- From: "Sanjiv Kumar Gupta, Noida" <sanjivg at noida dot hcltech dot com>
- To: Richard Henderson <rth at redhat dot com>
- Cc: jfc at mit dot edu, gcc-patches at gcc dot gnu dot org
- Date: Tue, 26 Nov 2002 16:22:59 +0530
- Subject: RE: PATCH : collecting more info in the init_alias_analysis pass
>This is an exact duplicate of your previous patch, correct?
>r~
No. The condition to detect invariant pseudo was missing
in the earlier patch.
I see that you have already checked in the idea in a better way
/* If we're inside init_alias_analysis, use new_reg_base_value
to reduce the number of relaxation iterations. */
if (new_reg_base_value && new_reg_base_value[regno])
return new_reg_base_value[regno];
But do you think that we need to do this for invariant pseduos only? as
suggested in the source code comments
line 2739, alias.c
/*
...
We could propagate more information in the first pass by making use
of REG_N_SETS to determine immediately that the alias information
for a pseudo is "constant".
..
i.e
if (new_reg_base_value && new_reg_base_value[regno]
&& REG_N_SETS(regno) == 1)
I have tested this also and this results in similar gains in compilation
speed.
--Sanjiv