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tree-optimization/113494 - Fix two observed regressions with r14-8206

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The following handles the situation where we lack a loop-closed
PHI for a virtual operand because a loop exit goes to a code
region not having any virtual use (an endless loop).  It also
handles the situation of edge redirection re-allocating a PHI node
in the destination block so we have to re-lookup that before
populating the new PHI argument.

	PR tree-optimization/113494
	* tree-vect-loop-manip.cc (slpeel_tree_duplicate_loop_to_edge_cfg):
	Handle endless loop on exit.  Handle re-allocated PHI.
This commit is contained in:
Richard Biener 2024-01-19 09:23:48 +01:00
parent 3670fb86bc
commit 6ce7008cfa
1 changed files with 21 additions and 5 deletions
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26
gcc/tree-vect-loop-manip.cc
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@ -1629,11 +1629,17 @@ slpeel_tree_duplicate_loop_to_edge_cfg (class loop *loop, edge loop_exit,
alt_loop_exit_block = split_edge (exit);
if (!need_virtual_phi)
continue;
if (vphi_def && !vphi)
vphi = create_phi_node (copy_ssa_name (vphi_def),
alt_loop_exit_block);
if (vphi_def)
add_phi_arg (vphi, vphi_def, exit, UNKNOWN_LOCATION);
{
if (!vphi)
vphi = create_phi_node (copy_ssa_name (vphi_def),
alt_loop_exit_block);
else
/* Edge redirection might re-allocate the PHI node
so we have to rediscover it. */
vphi = get_virtual_phi (alt_loop_exit_block);
add_phi_arg (vphi, vphi_def, exit, UNKNOWN_LOCATION);
}
}
set_immediate_dominator (CDI_DOMINATORS, new_preheader,
@ -1748,7 +1754,17 @@ slpeel_tree_duplicate_loop_to_edge_cfg (class loop *loop, edge loop_exit,
if (virtual_operand_p (alt_arg))
{
gphi *vphi = get_virtual_phi (alt_loop_exit_block);
alt_arg = gimple_phi_result (vphi);
/* ??? When the exit yields to a path without
any virtual use we can miss a LC PHI for the
live virtual operand. Simply choosing the
one live at the start of the loop header isn't
correct, but we should get here only with
early-exit vectorization which will move all
defs after the main exit, so leave a temporarily
wrong virtual operand in place. This happens
for gcc.c-torture/execute/20150611-1.c */
if (vphi)
alt_arg = gimple_phi_result (vphi);
}
edge main_e = single_succ_edge (alt_loop_exit_block);
SET_PHI_ARG_DEF_ON_EDGE (to_phi, main_e, alt_arg);