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Re: [PATCH] Improve overhead of tree-affine.c a bit
- From: Kyrill Tkachov <kyrylo dot tkachov at foss dot arm dot com>
- To: Richard Biener <rguenther at suse dot de>, "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
- Date: Mon, 10 Dec 2018 13:57:59 +0000
- Subject: Re: [PATCH] Improve overhead of tree-affine.c a bit
- References: <alpine.LSU.2.20.1812101440550.1827@zhemvz.fhfr.qr>
Hi Richard,
On 10/12/18 13:44, Richard Biener wrote:
When working on PR63184 I noticed that tree-affine.c is still one of
the gimple_assign_rhs_to_tree callers and does so quite aggressively
for no good reason. The following restricts it to the cases we
handle in tree_to_aff_combination, axing one unreachable case.
It also makes sure to cache expanded combinations with SSA names
as keys rather than a GENERIC conversion tree which isn't shared
anyways.
Bootstrapped and tested on x86_64-unknown-linux-gnu, object files
in gcc/ are the same patched/unpatched with the exception of
tree-affine.o.
Applied to trunk.
Richard.
2018-12-10 Richard Biener <rguenther@suse.de>
* tree-affine.c (tree_to_aff_combination): Remove unreachable
MEM_REF case.
(aff_combination_expand): Cache on SSA names, not possibly
on conversion trees. Avoid expanding cases we do not handle.
diff --git a/gcc/tree-affine.c b/gcc/tree-affine.c
index 96b479dfc4c..41c52ab468d 100644
--- a/gcc/tree-affine.c
+++ b/gcc/tree-affine.c
@@ -351,6 +351,7 @@ tree_to_aff_combination (tree expr, tree type, aff_tree *comb)
return;
case MEM_REF:
+ gcc_unreachable ();
if (TREE_CODE (TREE_OPERAND (expr, 0)) == ADDR_EXPR)
tree_to_aff_combination (TREE_OPERAND (TREE_OPERAND (expr, 0), 0),
type, comb);
The code after the gcc_unreachable is now dead and can be removed?
Thanks,
Kyrill
@@ -721,21 +722,39 @@ aff_combination_expand (aff_tree *comb ATTRIBUTE_UNUSED,
if (TREE_CODE_CLASS (code) == tcc_reference)
continue;
- if (!*cache)
- *cache = new hash_map<tree, name_expansion *>;
- name_expansion **slot = &(*cache)->get_or_insert (e);
- exp = *slot;
-
+ name_expansion **slot = NULL;
+ if (*cache)
+ slot = (*cache)->get (name);
+ exp = slot ? *slot : NULL;
if (!exp)
{
+ /* Only bother to handle cases tree_to_aff_combination will. */
+ switch (code)
+ {
+ case POINTER_PLUS_EXPR:
+ case PLUS_EXPR:
+ case MINUS_EXPR:
+ case MULT_EXPR:
+ case NEGATE_EXPR:
+ case BIT_NOT_EXPR:
+ CASE_CONVERT:
+ rhs = gimple_assign_rhs_to_tree (def);
+ break;
+ case ADDR_EXPR:
+ case INTEGER_CST:
+ case POLY_INT_CST:
+ rhs = gimple_assign_rhs1 (def);
+ break;
+ default:
+ continue;
+ }
+ tree_to_aff_combination (rhs, TREE_TYPE (name), ¤t);
exp = XNEW (struct name_expansion);
exp->in_progress = 1;
- *slot = exp;
- rhs = gimple_assign_rhs_to_tree (def);
- if (e != name)
- rhs = fold_convert (type, rhs);
-
- tree_to_aff_combination_expand (rhs, comb->type, ¤t, cache);
+ if (!*cache)
+ *cache = new hash_map<tree, name_expansion *>;
+ (*cache)->put (name, exp);
+ aff_combination_expand (¤t, cache);
exp->expansion = current;
exp->in_progress = 0;
}
@@ -746,6 +765,8 @@ aff_combination_expand (aff_tree *comb ATTRIBUTE_UNUSED,
gcc_assert (!exp->in_progress);
current = exp->expansion;
}
+ if (!useless_type_conversion_p (comb->type, current.type))
+ aff_combination_convert (¤t, comb->type);
/* Accumulate the new terms to TO_ADD, so that we do not modify
COMB while traversing it; include the term -coef * E, to remove