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From: Alexander Monakov <amonakov@ispras.ru>
To: "Kong, Lingling" <lingling.kong@intel.com>
Cc: "gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>,
	 "Liu, Hongtao" <hongtao.liu@intel.com>,
	Uros Bizjak <ubizjak@gmail.com>
Subject: Re: [PATCH 0/3] [APX CFCMOV] Support APX CFCMOV
Date: Fri, 14 Jun 2024 20:10:26 +0300 (MSK)	[thread overview]
Message-ID: <bc075cca-fb13-e411-38ac-4cc94777f157@ispras.ru> (raw)
In-Reply-To: <DM4PR11MB5487233633CD3F1E91C72A84ECC22@DM4PR11MB5487.namprd11.prod.outlook.com>


On Fri, 14 Jun 2024, Kong, Lingling wrote:

> APX CFCMOV[1] feature implements conditionally faulting which means that all memory faults are suppressed
> when the condition code evaluates to false and load or store a memory operand. Now we could load or store a
> memory operand may trap or fault for conditional move.
> 
> In middle-end, now we don't support a conditional move if we knew that a load
> from A or B could trap or fault.

Predicated loads&stores on Itanium don't trap either. They are modeled via
COND_EXEC on RTL. The late if-conversion pass (the instance that runs after
reload) is capable of introducing them.

> To enable CFCMOV, we add a target HOOK TARGET_HAVE_CONDITIONAL_MOVE_MEM_NOTRAP
> in if-conversion pass to allow convert to cmov.

Considering the above, is the new hook really necessary? Can you model the new
instructions via (cond_exec () (set ...)) instead of (set (if_then_else ...)) ?

Alexander

  parent reply	other threads:[~2024-06-14 17:10 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20240614025749.743388-1-lingling.kong@intel.com>
2024-06-14  3:11 ` Kong, Lingling
2024-06-14  6:52   ` Richard Biener
2024-06-14  6:58     ` Liu, Hongtao
2024-06-14  8:10       ` Richard Biener
2024-06-14 17:10   ` Alexander Monakov [this message]
2024-06-14 17:22     ` Jeff Law
2024-06-17  3:04       ` Hongtao Liu
2024-06-18  7:40         ` [PATCH v2 0/2] " Kong, Lingling
     [not found] ` <20240614025749.743388-2-lingling.kong@intel.com>
2024-06-14  3:11   ` [PATCH 1/3] [APX CFCMOV] Add a new target hook: TARGET_HAVE_CONDITIONAL_MOVE_MEM_NOTRAP Kong, Lingling
     [not found] ` <20240614025749.743388-3-lingling.kong@intel.com>
2024-06-14  3:11   ` [PATCH 2/3] [APX CFCMOV] Support APX CFCMOV in if_convert pass Kong, Lingling
     [not found] ` <20240614025749.743388-4-lingling.kong@intel.com>
2024-06-14  3:11   ` [PATCH 3/3] [APX CFCMOV] Support APX CFCMOV in backend Kong, Lingling

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