mirror/gcc
2
0
Fork 0
mirror of git://gcc.gnu.org/git/gcc.git synced 2025-04-21 14:30:59 +08:00
Code Issues Packages Projects Releases Wiki Activity

Ensure PHI equivalencies do not dominate the argument edge.

Browse Source 
When we create an equivalency between a PHI definition and an argument,
ensure the definition does not dominate the incoming argument edge.

	PR tree-optimization/108139
	PR tree-optimization/109462
	* gimple-range-cache.cc (ranger_cache::fill_block_cache): Remove
	equivalency check for PHI nodes.
	* gimple-range-fold.cc (fold_using_range::range_of_phi): Ensure def
	does not dominate single-arg equivalency edges.
This commit is contained in:
Andrew MacLeod 2023-04-12 13:10:55 -04:00
parent 52bb22bb5e
commit 9c2a5db997
2 changed files with 22 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
gcc/gimple-range-cache.cc
View File

@ -1220,7 +1220,7 @@ ranger_cache::fill_block_cache (tree name, basic_block bb, basic_block def_bb)
// See if any equivalences can refine it.
// PR 109462, like 108139 below, a one way equivalence introduced
// by a PHI node can also be through the definition side. Disallow it.
if (m_oracle && !is_a<gphi *> (SSA_NAME_DEF_STMT (name)))
if (m_oracle)
{
tree equiv_name;
relation_kind rel;
@ -1237,13 +1237,6 @@ ranger_cache::fill_block_cache (tree name, basic_block bb, basic_block def_bb)
if (!m_gori.has_edge_range_p (equiv_name))
continue;
// PR 108139. It is hazardous to assume an equivalence with
// a PHI is the same value. The PHI may be an equivalence
// via UNDEFINED arguments which is really a one way equivalence.
// PHIDEF == name, but name may not be == PHIDEF.
if (is_a<gphi *> (SSA_NAME_DEF_STMT (equiv_name)))
continue;
// Check if the equiv definition dominates this block
if (equiv_bb == bb ||
(equiv_bb && !dominated_by_p (CDI_DOMINATORS, bb, equiv_bb)))

23
gcc/gimple-range-fold.cc
View File

@ -795,9 +795,28 @@ fold_using_range::range_of_phi (vrange &r, gphi *phi, fur_source &src)
// If the PHI boils down to a single effective argument, look at it.
if (single_arg)
{
// Symbolic arguments are equivalences.
// Symbolic arguments can be equivalences.
if (gimple_range_ssa_p (single_arg))
src.register_relation (phi, VREL_EQ, phi_def, single_arg);
{
// Only allow the equivalence if the PHI definition does not
// dominate any incoming edge for SINGLE_ARG.
// See PR 108139 and 109462.
basic_block bb = gimple_bb (phi);
if (!dom_info_available_p (CDI_DOMINATORS))
single_arg = NULL;
else
for (x = 0; x < gimple_phi_num_args (phi); x++)
if (gimple_phi_arg_def (phi, x) == single_arg
&& dominated_by_p (CDI_DOMINATORS,
gimple_phi_arg_edge (phi, x)->src,
bb))
{
single_arg = NULL;
break;
}
if (single_arg)
src.register_relation (phi, VREL_EQ, phi_def, single_arg);
}
else if (src.get_operand (arg_range, single_arg)
&& arg_range.singleton_p ())
{