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Re: [patch][autovect]Add option ftree-vect-loop-version
- From: Devang Patel <dpatel at apple dot com>
- To: Keith Besaw <kbesaw at us dot ibm dot com>
- Cc: gcc-patches at gcc dot gnu dot org, Dorit Naishlos <DORIT at il dot ibm dot com>
- Date: Fri, 18 Mar 2005 08:29:18 -0800
- Subject: Re: [patch][autovect]Add option ftree-vect-loop-version
- References: <OFA0E4BB19.70677BE3-ON86256FC8.0022DEF8-86256FC8.0027C6D5@us.ibm.com>
On Mar 17, 2005, at 11:14 PM, Keith Besaw wrote:
This patch adds the ftree-vect-loop-version option.
Data alignment and data dependencies that cannot be determined at
compile-time may inhibit vectorization. One way around this is to
generate
a vectorized version along with the original scalar version of a
loop and
add
runtime alignment or dependence checks that determine which loop is
actually
executed. Because this can cause code bloat this patch adds a new
option
so that loop versioning for vectorization can be turned off.
The default is to perform loop versioning when the ftree-vectorize
option
is specified.
fno-tree-vect-loop-version is used to turn off vectorizing by loop
versioning.
Just a thought, do we want to tie this with optimization for size flag,
-Os also. I mean if -Os is used, turn off -ftree-vect-loop-version by
default.
-
Devang