> On 15 Nov 2025, at 8:36 am, Kugan Vivekanandarajah <[email protected]> > wrote: > > External email: Use caution opening links or attachments > > > Hi, > >>> >>> I think we want to solve two problems >>> 1) Handle situation when statement is duplicated (unrolling, loop >>> header copying etc.) and thus different locations in program >>> corresponds to different copies. >>> >>> Current code simply picks address with maximal count (expecting that >>> the statemnt perhaps spans multiple BBs) while we should really sum >>> counts of execution of different copies. >>> 1) Handle situation where single address implies multiple executions >>> of the same statement (i.e. after vectorization) >>> > > Here is the revised patch-set. In this:2 > 1. I have dropped gcov changes to 32bit discriminator. Instead I have > changed autofdo tools to handle multiplicity and copy-id. > I have put-up a pull request to autfdo tools as > https://github.com/google/autofdo/pull/257. This means all the changes to > auto-profile pass is not needed for this. > We could still add 32bit support if there is a need as a follow up. > > I have the split the patch into > 1. Hierarchical discriminate support > 2. Change vectoriser to add hierarchal discriminator > 3. Adding hierarchical discriminate for loop versioning > 4. Adding hierarchical discriminate for loop unrolling >
Hi,
This patch introduces the basic infrastructure for hierarchical
discriminators with format [Base:8][Multiplicity:7][CopyID:11][Unused:6].
This is a placeholder and values can be changed based on feedback.
It adds helper functions to create and extract discriminator components.
gcc/ChangeLog:
* Makefile.in: Add hierarchical_discriminator.o to OBJS.
* hierarchical_discriminator.cc: New file.
* hierarchical_discriminator.h: New file.
* input.cc (location_with_discriminator_components): New function.
(get_discriminator_components_from_loc): Likewise.
* input.h (DISCR_BASE_BITS): New constant.
(DISCR_MULTIPLICITY_BITS): Likewise.
(DISCR_COPYID_BITS): Likewise.
(DISCR_UNUSED_BITS): Likewise.
(DISCR_BASE_MASK): Likewise.
(DISCR_MULTIPLICITY_MASK): Likewise.
(DISCR_COPYID_MASK): Likewise.
(DISCR_BASE_SHIFT): Likewise.
(DISCR_MULTIPLICITY_SHIFT): Likewise.
(DISCR_COPYID_SHIFT): Likewise.
(DISCR_BASE_MAX): Likewise.
(DISCR_MULTIPLICITY_MAX): Likewise.
(DISCR_COPYID_MAX): Likewise.
(location_with_discriminator_components): New function declaration.
(get_discriminator_components_from_loc): Likewise.
Signed-off-by: Kugan Vivekanandarajah <[email protected]>
Thanks,
Kugan
0001-Autofdo-Add-hierarchical-discriminator-support.patch
Description: 0001-Autofdo-Add-hierarchical-discriminator-support.patch
