From: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
To: Aldy Hernandez <aldyh@redhat.com>
Cc: rep.dot.nop@gmail.com, Andrew MacLeod <amacleod@redhat.com>,
GCC patches <gcc-patches@gcc.gnu.org>
Subject: Re: [COMMITTED] Kill second order relations in the path solver.
Date: Thu, 28 Oct 2021 01:55:30 +0200 [thread overview]
Message-ID: <20211028015530.6fd3ee60@nbbrfq> (raw)
In-Reply-To: <20211027181323.395724-1-aldyh@redhat.com>
On Wed, 27 Oct 2021 20:13:21 +0200
Aldy Hernandez via Gcc-patches <gcc-patches@gcc.gnu.org> wrote:
[would have to think about this some more but it's late here. Nits:]
> diff --git a/gcc/value-relation.cc b/gcc/value-relation.cc
> index 2acf375ca9a..0ad4f7a9495 100644
> --- a/gcc/value-relation.cc
> +++ b/gcc/value-relation.cc
> @@ -1297,8 +1297,9 @@ path_oracle::killing_def (tree ssa)
> fprintf (dump_file, "\n");
> }
>
> + unsigned v = SSA_NAME_VERSION (ssa);
> bitmap b = BITMAP_ALLOC (&m_bitmaps);
> - bitmap_set_bit (b, SSA_NAME_VERSION (ssa));
> + bitmap_set_bit (b, v);
> equiv_chain *ptr = (equiv_chain *) obstack_alloc (&m_chain_obstack,
> sizeof (equiv_chain));
> ptr->m_names = b;
> @@ -1306,6 +1307,24 @@ path_oracle::killing_def (tree ssa)
> ptr->m_next = m_equiv.m_next;
> m_equiv.m_next = ptr;
> bitmap_ior_into (m_equiv.m_names, b);
> +
> + // Walk the relation list an remove SSA from any relations.
s/an /and /
> + if (!bitmap_bit_p (m_relations.m_names, v))
> + return;
> +
> + bitmap_clear_bit (m_relations.m_names, v);
IIRC bitmap_clear_bit returns true if the bit was set, false otherwise,
so should be used as if(!bitmap_clear_bit) above.
I would not be surprised if this generates better code as we probably
do not grok to optimize the !bit_p else clear_bit combo. Shame (?).
> + relation_chain **prev = &(m_relations.m_head);
s/[()]//
thanks,
> + relation_chain *next = NULL;
> + for (relation_chain *ptr = m_relations.m_head; ptr; ptr = next)
> + {
> + gcc_checking_assert (*prev == ptr);
> + next = ptr->m_next;
> + if (SSA_NAME_VERSION (ptr->op1 ()) == v
> + || SSA_NAME_VERSION (ptr->op2 ()) == v)
> + *prev = ptr->m_next;
> + else
> + prev = &(ptr->m_next);
> + }
> }
>
> // Register relation K between SSA1 and SSA2, resolving unknowns by
next prev parent reply other threads:[~2021-10-27 23:55 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-27 18:13 Aldy Hernandez
2021-10-27 18:13 ` [COMMITTED] Reorder relation calculating code " Aldy Hernandez
2021-10-27 18:13 ` [COMMITTED] Kill known equivalences before a new assignment " Aldy Hernandez
2021-10-27 23:55 ` Bernhard Reutner-Fischer [this message]
2021-11-01 14:10 ` redundant bitmap_bit_p followed by bitmap_clear_bit [was: Re: [COMMITTED] Kill second order relations in the path solver.] Bernhard Reutner-Fischer
2021-11-01 14:21 ` Aldy Hernandez
2021-11-01 21:02 ` Bernhard Reutner-Fischer
2021-11-02 13:43 ` Richard Biener
2021-11-02 18:01 ` Richard Sandiford
2021-11-02 21:00 ` Bernhard Reutner-Fischer
2021-11-03 8:01 ` Richard Biener
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