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tree-optimization/110434 - avoid <retval> ={v} {CLOBBER} from NRV

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When NRV replaces a local variable with <retval> it also replaces
occurences in clobbers.  This leads to <retval> being clobbered
before the return of it which is strictly invalid but harmless in
practice since there's no pass after NRV which would remove
earlier stores.

The following fixes this nevertheless.

	PR tree-optimization/110434
	* tree-nrv.cc (pass_nrv::execute): Remove CLOBBERs of
	VAR we replace with <retval>.
This commit is contained in:
Richard Biener 2023-06-28 11:27:45 +02:00
parent c7e87e8243
commit 4bf76b5b6d
1 changed files with 11 additions and 1 deletions
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12
gcc/tree-nrv.cc
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@ -264,7 +264,17 @@ pass_nrv::execute (function *fun)
data.modified = 0;
walk_gimple_op (stmt, finalize_nrv_r, &wi);
if (data.modified)
update_stmt (stmt);
{
/* If this is a CLOBBER of VAR, remove it. */
if (gimple_clobber_p (stmt))
{
unlink_stmt_vdef (stmt);
gsi_remove (&gsi, true);
release_defs (stmt);
continue;
}
update_stmt (stmt);
}
gsi_next (&gsi);
}
}