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Re: [patch] Decrease # of update_stmt calls from alias analysis
- From: Zdenek Dvorak <rakdver at atrey dot karlin dot mff dot cuni dot cz>
- To: Diego Novillo <dnovillo at redhat dot com>
- Cc: gcc-patches at gcc dot gnu dot org, Michael Matz <matz at suse dot de>, Andrew MacLeod <amacleod at redhat dot com>, dberlin at dberlin dot org
- Date: Wed, 1 Mar 2006 14:48:15 +0100
- Subject: Re: [patch] Decrease # of update_stmt calls from alias analysis
- References: <20060227170004.GA9176@atrey.karlin.mff.cuni.cz> <1141149999.10812.362.camel@localhost.localdomain> <Pine.LNX.4.58.0602281908051.20821@wotan.suse.de> <1141154104.6054.27.camel@localhost> <20060301102318.GA19301@atrey.karlin.mff.cuni.cz> <44059442.6020900@redhat.com>
Hello,
> > * tree-flow.h (struct stmt_ann_d): Add has_virtual_ops field.
> > * tree-ssa-structalias.c (find_func_aliases): Only mark
> > the statements that may have virtual operands for rescanning.
> > * tree-ssa-operands.c (build_ssa_operands, get_expr_operands,
> > get_asm_expr_operands, get_call_expr_operands): Set has_virtual_ops
> > field.
> >
> No. Not another state flag to keep up-to-date. Particularly if it
> gives no benefit.
huh? No benefit??? I thought the reduction of number of update_stmt
calls is self-explanatory, but just to make it clear -- this patch
improves compile time measurably, for example by almost 1% on combine.i at
-O2.
> Use stmt_references_memory_p, if you must.
Given that the point of the patch is to avoid need to scan the
statement, this does not seem like a good solution to me.
Zdenek