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DSE: Add LEN_MASK_STORE analysis into DSE and fix LEN_STORE

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Hi, Richi.

This patch is adding LEN_MASK_STORE into DSE.

My understanding is LEN_MASK_STORE is predicated by mask and len.
No matter len is constant or not, the ao_ref should be the same as MASK_STORE.

Wheras for LEN_STORE, when len is constant, we use (len - bias), otherwise, it's
the same as MASK_STORE/LEN_MASK_STORE.

Not sure whether I am on the same page with you, feel free to correct me.

Thanks.

gcc/ChangeLog:

	* tree-ssa-dse.cc (initialize_ao_ref_for_dse): Add LEN_MASK_STORE and
	fix LEN_STORE.
	(dse_optimize_stmt): Add LEN_MASK_STORE.
This commit is contained in:
Ju-Zhe Zhong 2023-06-26 15:43:42 +08:00 • committed by Pan Li
parent f0deeefebb
commit 38ead98b2f
1 changed files with 31 additions and 16 deletions
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47
gcc/tree-ssa-dse.cc
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@ -48,6 +48,7 @@ along with GCC; see the file COPYING3. If not see
#include "tree-ssa-loop-niter.h"
#include "cfgloop.h"
#include "tree-data-ref.h"
#include "internal-fn.h"
/* This file implements dead store elimination.
@ -157,23 +158,36 @@ initialize_ao_ref_for_dse (gimple *stmt, ao_ref *write, bool may_def_ok = false)
switch (gimple_call_internal_fn (stmt))
{
case IFN_LEN_STORE:
ao_ref_init_from_ptr_and_size
(write, gimple_call_arg (stmt, 0),
int_const_binop (MINUS_EXPR,
gimple_call_arg (stmt, 2),
gimple_call_arg (stmt, 4)));
return true;
case IFN_MASK_STORE:
/* We cannot initialize a must-def ao_ref (in all cases) but we
can provide a may-def variant. */
if (may_def_ok)
{
ao_ref_init_from_ptr_and_size
(write, gimple_call_arg (stmt, 0),
TYPE_SIZE_UNIT (TREE_TYPE (gimple_call_arg (stmt, 3))));
return true;
}
break;
case IFN_LEN_MASK_STORE:
{
int stored_value_index
= internal_fn_stored_value_index (gimple_call_internal_fn (stmt));
if (gimple_call_internal_fn (stmt) == IFN_LEN_STORE)
{
tree len = gimple_call_arg (stmt, 2);
tree bias = gimple_call_arg (stmt, 4);
if (tree_fits_uhwi_p (len))
{
ao_ref_init_from_ptr_and_size (write,
gimple_call_arg (stmt, 0),
int_const_binop (MINUS_EXPR,
len, bias));
return true;
}
}
/* We cannot initialize a must-def ao_ref (in all cases) but we
can provide a may-def variant. */
if (may_def_ok)
{
ao_ref_init_from_ptr_and_size (
write, gimple_call_arg (stmt, 0),
TYPE_SIZE_UNIT (
TREE_TYPE (gimple_call_arg (stmt, stored_value_index))));
return true;
}
break;
}
default:;
}
}
@ -1502,6 +1516,7 @@ dse_optimize_stmt (function *fun, gimple_stmt_iterator *gsi, sbitmap live_bytes)
{
case IFN_LEN_STORE:
case IFN_MASK_STORE:
case IFN_LEN_MASK_STORE:
{
enum dse_store_status store_status;
store_status = dse_classify_store (&ref, stmt, false, live_bytes);