There are a lot of dead statements in this testcase which a casts. These
were being added to the list of partial equivalences and causing some
serious compile time issues.
Rangers cache loops through equivalences when its propagating on-entry
values, so if the partial equivalence list is very large, it can consume
a lot of time. Typically, partial equivalence lists are small. In
this case, a lot of dead stmts were not removed, so there was no
redundancy elimination and it was causing an issue.
Bootstrapped on x86_64-pc-linux-gnu with no regressions. Pushed.
Andrew
From 425964b77ab5b9631e914965a7397303215c77a1 Mon Sep 17 00:00:00 2001
From: Andrew MacLeod <amacl...@redhat.com>
Date: Thu, 12 Oct 2023 17:06:36 -0400
Subject: [PATCH] Do not add partial equivalences with no uses.
PR tree-optimization/111622
* value-relation.cc (equiv_oracle::add_partial_equiv): Do not
register a partial equivalence if an operand has no uses.
---
gcc/value-relation.cc | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/gcc/value-relation.cc b/gcc/value-relation.cc
index fc792a4d5bc..0ed5f93d184 100644
--- a/gcc/value-relation.cc
+++ b/gcc/value-relation.cc
@@ -389,6 +389,9 @@ equiv_oracle::add_partial_equiv (relation_kind r, tree op1, tree op2)
// In either case, if PE2 has an entry, we simply do nothing.
if (pe2.members)
return;
+ // If there are no uses of op2, do not register.
+ if (has_zero_uses (op2))
+ return;
// PE1 is the LHS and already has members, so everything in the set
// should be a slice of PE2 rather than PE1.
pe2.code = pe_min (r, pe1.code);
@@ -406,6 +409,9 @@ equiv_oracle::add_partial_equiv (relation_kind r, tree op1, tree op2)
}
if (pe2.members)
{
+ // If there are no uses of op1, do not register.
+ if (has_zero_uses (op1))
+ return;
pe1.ssa_base = pe2.ssa_base;
// If pe2 is a 16 bit value, but only an 8 bit copy, we can't be any
// more than an 8 bit equivalence here, so choose MIN value.
@@ -415,6 +421,9 @@ equiv_oracle::add_partial_equiv (relation_kind r, tree op1, tree op2)
}
else
{
+ // If there are no uses of either operand, do not register.
+ if (has_zero_uses (op1) || has_zero_uses (op2))
+ return;
// Neither name has an entry, simply create op1 as slice of op2.
pe2.code = bits_to_pe (TYPE_PRECISION (TREE_TYPE (op2)));
if (pe2.code == VREL_VARYING)
--
2.41.0
