Re: redundant bitmap_bit_p followed by bitmap_clear_bit [was: Re: [COMMITTED] Kill second order relations in the path solver.]
On Tue, Nov 2, 2021 at 10:00 PM Bernhard Reutner-Fischer
wrote:
>
> On 2 November 2021 14:43:38 CET, Richard Biener
> wrote:
> >On Mon, Nov 1, 2021 at 10:02 PM Bernhard Reutner-Fischer via
> >Gcc-patches wrote:
> >>
> >> On Mon, 1 Nov 2021 15:21:03 +0100
> >> Aldy Hernandez wrote:
> >>
> >> > I'm not convinced this makes the code clearer to read, especially if
> >> > it's not on a critical path. But if you feel strongly, please submit
> >> > a patch ;-).
> >>
> >> No i don't feel strongly about it.
> >> Compiling e.g. -O2 ira.o
> >> # Overhead Samples Command Shared Object Symbol
> >> # ... . .
> >> #
> >>100.00% 4197 cc1plus cc1plus[.] mark_reachable_blocks
> >>100.00% 22000 cc1plus cc1plus[.]
> >> path_oracle::killing_def
> >> and the mark_elimination is reload.
> >> So it's not just a handful of calls saved but some. And it would be
> >> smaller code as it saves a call. Well maybe another day.
> >
> >Note that single bit set/clear are already implemented as test && set/clear.
> >Note that unfortunately the sbitmap bitmap_set/clear_bit overloads do not
> >return the previous state of the bit. Maybe providing
>
> All 3 spots here, dse, ira and killing_def do not look at the bit but use it
> as a bool, fwiw.
> These 3 are the only users I (resp coccinelle) found who do the redundant
> bitmap_bit_p, bitmap_clear_bit.
>
> >bitmap_test_and_set_bit () and bitmap_test_and_clear_bit () would be
> >better (but note we currently return true when the bit changed, not when
> >it was set).
>
> A big portion of users of bitmap_bit_p could use a bitmap_bit_p that returns
> bool as is.
> The rest would know the bit they asked for, no?
> Hence bitmap_bit_p could be changed to return a bool rather easily. testb
> instead of testl on x86_64 fwiw.
> thanks,
Yes, I think bitmap_bit_p returns [0, 1] already, 'int' is just some
pre-bool standard return type...
I'm going to test a patch changing the signature.
Richard.
>
> >
> >Richard.
> >
> >> thanks,
> >> >
> >> > Aldy
> >> >
> >> > On Mon, Nov 1, 2021 at 3:10 PM Bernhard Reutner-Fischer
> >> > wrote:
> >> > >
> >> > > On Thu, 28 Oct 2021 01:55:30 +0200
> >> > > Bernhard Reutner-Fischer wrote:
> >> > >
> >> > > > On Wed, 27 Oct 2021 20:13:21 +0200
> >> > > > Aldy Hernandez via Gcc-patches wrote:
> >> > >
> >> > > > > @@ -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.
> >> > >
> >> > > > > + relation_chain **prev = &(m_relations.m_head);
> >> > > >
> >> > > > s/[()]//
> >> > > > thanks,
> >> > >
> >> > > There seems to be two other spots where a redundant bitmap_bit_p checks
> >> > > if we want to bitmap_clear_bit. In dse and ira.
> >> > > Like:
> >> > > $ cat ~/coccinelle/gcc_bitmap_bit_p-0.cocci ; echo EOF
> >> > > // replace redundant bitmap_bit_p() bitmap_clear_bit with the latter
> >> > > @ rule1 @
> >> > > identifier fn;
> >> > > expression bitmap, bit;
> >> > > @@
> >> > >
> >> > > fn(...) {
> >> > > <...
> >> > > (
> >> > > -if (bitmap_bit_p (bitmap, bit))
> >> > > +if (bitmap_clear_bit (bitmap, bit))
> >> > > {
> >> > > ...
> >> > > - bitmap_clear_bit (bitmap, bit);
> >> > > ...
> >> > > }
> >> > > |
> >> > > -if (bitmap_bit_p (bitmap, bit))
> >> > > +if (bitmap_clear_bit (bitmap, bit))
> >> > > {
> >> > > ...
> >> > > }
> >> > > ...
> >> > > -bitmap_clear_bit (bitmap, bit);
> >> > > )
> >> > > ...>
> >> > > }
> >> > > EOF
> >> > > $ find gcc/ -type f -a \( -name "*.c" -o -name "*.cc" \) -a \( ! -path
> >> > > "gcc/testsuite/*" -a ! -path "gcc/contrib/*" \) -exec spatch -sp_file
> >> > > ~/coccinelle/gcc_bitmap_bit_p-0.cocci --show-diff {} \;
> >> > > diff =
> >> > > --- gcc/dse.c
> >> > > +++ /tmp/cocci-output-1104419-443759-dse.c
> >> > > @@ -3238,9 +3238,8 @@ mark_reachable_blocks (sbitmap unreachab
> >> > >edge e;
> >> > >edge_iterator ei;
> >> > >
> >> > > - if (bitmap_bit_p (unreachable_blocks, bb->index))
> >> > > + if (bitmap_clear_bit(unreachable_blocks, bb->index))
> >> > > {
> >> > > - bitmap_clear_bit (unreachable_blocks, bb->index);
> >> > >FOR_EACH_EDGE (e, ei, bb->preds)
> >> > > {
> >> > > mark_reachable_blocks (unreachable_blocks, e->src);
> >> > > diff =
> >> > > --- gcc/ira.c
> >> > > +++ /tmp/cocci-output-1104678-d8679a-ira.c
> >> > > @@ -2944,17 +2944,15 @@
Re: redundant bitmap_bit_p followed by bitmap_clear_bit [was: Re: [COMMITTED] Kill second order relations in the path solver.]
On 2 November 2021 14:43:38 CET, Richard Biener
wrote:
>On Mon, Nov 1, 2021 at 10:02 PM Bernhard Reutner-Fischer via
>Gcc-patches wrote:
>>
>> On Mon, 1 Nov 2021 15:21:03 +0100
>> Aldy Hernandez wrote:
>>
>> > I'm not convinced this makes the code clearer to read, especially if
>> > it's not on a critical path. But if you feel strongly, please submit
>> > a patch ;-).
>>
>> No i don't feel strongly about it.
>> Compiling e.g. -O2 ira.o
>> # Overhead Samples Command Shared Object Symbol
>> # ... . .
>> #
>>100.00% 4197 cc1plus cc1plus[.] mark_reachable_blocks
>>100.00% 22000 cc1plus cc1plus[.]
>> path_oracle::killing_def
>> and the mark_elimination is reload.
>> So it's not just a handful of calls saved but some. And it would be
>> smaller code as it saves a call. Well maybe another day.
>
>Note that single bit set/clear are already implemented as test && set/clear.
>Note that unfortunately the sbitmap bitmap_set/clear_bit overloads do not
>return the previous state of the bit. Maybe providing
All 3 spots here, dse, ira and killing_def do not look at the bit but use it as
a bool, fwiw.
These 3 are the only users I (resp coccinelle) found who do the redundant
bitmap_bit_p, bitmap_clear_bit.
>bitmap_test_and_set_bit () and bitmap_test_and_clear_bit () would be
>better (but note we currently return true when the bit changed, not when
>it was set).
A big portion of users of bitmap_bit_p could use a bitmap_bit_p that returns
bool as is.
The rest would know the bit they asked for, no?
Hence bitmap_bit_p could be changed to return a bool rather easily. testb
instead of testl on x86_64 fwiw.
thanks,
>
>Richard.
>
>> thanks,
>> >
>> > Aldy
>> >
>> > On Mon, Nov 1, 2021 at 3:10 PM Bernhard Reutner-Fischer
>> > wrote:
>> > >
>> > > On Thu, 28 Oct 2021 01:55:30 +0200
>> > > Bernhard Reutner-Fischer wrote:
>> > >
>> > > > On Wed, 27 Oct 2021 20:13:21 +0200
>> > > > Aldy Hernandez via Gcc-patches wrote:
>> > >
>> > > > > @@ -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.
>> > >
>> > > > > + relation_chain **prev = &(m_relations.m_head);
>> > > >
>> > > > s/[()]//
>> > > > thanks,
>> > >
>> > > There seems to be two other spots where a redundant bitmap_bit_p checks
>> > > if we want to bitmap_clear_bit. In dse and ira.
>> > > Like:
>> > > $ cat ~/coccinelle/gcc_bitmap_bit_p-0.cocci ; echo EOF
>> > > // replace redundant bitmap_bit_p() bitmap_clear_bit with the latter
>> > > @ rule1 @
>> > > identifier fn;
>> > > expression bitmap, bit;
>> > > @@
>> > >
>> > > fn(...) {
>> > > <...
>> > > (
>> > > -if (bitmap_bit_p (bitmap, bit))
>> > > +if (bitmap_clear_bit (bitmap, bit))
>> > > {
>> > > ...
>> > > - bitmap_clear_bit (bitmap, bit);
>> > > ...
>> > > }
>> > > |
>> > > -if (bitmap_bit_p (bitmap, bit))
>> > > +if (bitmap_clear_bit (bitmap, bit))
>> > > {
>> > > ...
>> > > }
>> > > ...
>> > > -bitmap_clear_bit (bitmap, bit);
>> > > )
>> > > ...>
>> > > }
>> > > EOF
>> > > $ find gcc/ -type f -a \( -name "*.c" -o -name "*.cc" \) -a \( ! -path
>> > > "gcc/testsuite/*" -a ! -path "gcc/contrib/*" \) -exec spatch -sp_file
>> > > ~/coccinelle/gcc_bitmap_bit_p-0.cocci --show-diff {} \;
>> > > diff =
>> > > --- gcc/dse.c
>> > > +++ /tmp/cocci-output-1104419-443759-dse.c
>> > > @@ -3238,9 +3238,8 @@ mark_reachable_blocks (sbitmap unreachab
>> > >edge e;
>> > >edge_iterator ei;
>> > >
>> > > - if (bitmap_bit_p (unreachable_blocks, bb->index))
>> > > + if (bitmap_clear_bit(unreachable_blocks, bb->index))
>> > > {
>> > > - bitmap_clear_bit (unreachable_blocks, bb->index);
>> > >FOR_EACH_EDGE (e, ei, bb->preds)
>> > > {
>> > > mark_reachable_blocks (unreachable_blocks, e->src);
>> > > diff =
>> > > --- gcc/ira.c
>> > > +++ /tmp/cocci-output-1104678-d8679a-ira.c
>> > > @@ -2944,17 +2944,15 @@ mark_elimination (int from, int to)
>> > >FOR_EACH_BB_FN (bb, cfun)
>> > > {
>> > >r = DF_LR_IN (bb);
>> > > - if (bitmap_bit_p (r, from))
>> > > + if (bitmap_clear_bit(r, from))
>> > > {
>> > > - bitmap_clear_bit (r, from);
>> > > bitmap_set_bit (r, to);
>> > > }
>> > >if (! df_live)
>> > > continue;
>> > >r = DF_LIVE_IN (bb);
>> > > - if (bitmap_bit_p (r, from))
>> > > + if (bitmap_clear_bit(r, from))
>> > >
Re: redundant bitmap_bit_p followed by bitmap_clear_bit [was: Re: [COMMITTED] Kill second order relations in the path solver.]
Richard Biener via Gcc-patches writes: > On Mon, Nov 1, 2021 at 10:02 PM Bernhard Reutner-Fischer via > Gcc-patches wrote: >> >> On Mon, 1 Nov 2021 15:21:03 +0100 >> Aldy Hernandez wrote: >> >> > I'm not convinced this makes the code clearer to read, especially if >> > it's not on a critical path. But if you feel strongly, please submit >> > a patch ;-). >> >> No i don't feel strongly about it. >> Compiling e.g. -O2 ira.o >> # Overhead Samples Command Shared Object Symbol >> # ... . . >> # >>100.00% 4197 cc1plus cc1plus[.] mark_reachable_blocks >>100.00% 22000 cc1plus cc1plus[.] >> path_oracle::killing_def >> and the mark_elimination is reload. >> So it's not just a handful of calls saved but some. And it would be >> smaller code as it saves a call. Well maybe another day. > > Note that single bit set/clear are already implemented as test && set/clear. > Note that unfortunately the sbitmap bitmap_set/clear_bit overloads do not > return the previous state of the bit. +1 that it would good if the sbitmap versions behaved like the bitmap versions. Always low-key bothered me that they didn't do this when I hit it, but never got round to do anything about it... Bitmap operations consistently show up high in the profiles, so IMO using the return value of bitmap_set_bit and bitmap_clear_bit should be the preferred style. Not all uses are performance-critical, of course, but code tends to get copied around. Having all code do it the fast way reduces the risk that slow code gets copied to code that needs to be fast. :-) > Maybe providing bitmap_test_and_set_bit () and > bitmap_test_and_clear_bit () would be better (but note we currently > return true when the bit changed, not when it was set). Yeah, maybe it's just familiarity, but I find the: if (bitmap_set_bit (bb, i)) ...something changed... thing easier to follow than: if (!bitmap_test_and_set_bit (bb, i)) ...something changed... Thanks, Richard
Re: redundant bitmap_bit_p followed by bitmap_clear_bit [was: Re: [COMMITTED] Kill second order relations in the path solver.]
On Mon, Nov 1, 2021 at 10:02 PM Bernhard Reutner-Fischer via
Gcc-patches wrote:
>
> On Mon, 1 Nov 2021 15:21:03 +0100
> Aldy Hernandez wrote:
>
> > I'm not convinced this makes the code clearer to read, especially if
> > it's not on a critical path. But if you feel strongly, please submit
> > a patch ;-).
>
> No i don't feel strongly about it.
> Compiling e.g. -O2 ira.o
> # Overhead Samples Command Shared Object Symbol
> # ... . .
> #
>100.00% 4197 cc1plus cc1plus[.] mark_reachable_blocks
>100.00% 22000 cc1plus cc1plus[.] path_oracle::killing_def
> and the mark_elimination is reload.
> So it's not just a handful of calls saved but some. And it would be
> smaller code as it saves a call. Well maybe another day.
Note that single bit set/clear are already implemented as test && set/clear.
Note that unfortunately the sbitmap bitmap_set/clear_bit overloads do not
return the previous state of the bit. Maybe providing
bitmap_test_and_set_bit () and bitmap_test_and_clear_bit () would be
better (but note we currently return true when the bit changed, not when
it was set).
Richard.
> thanks,
> >
> > Aldy
> >
> > On Mon, Nov 1, 2021 at 3:10 PM Bernhard Reutner-Fischer
> > wrote:
> > >
> > > On Thu, 28 Oct 2021 01:55:30 +0200
> > > Bernhard Reutner-Fischer wrote:
> > >
> > > > On Wed, 27 Oct 2021 20:13:21 +0200
> > > > Aldy Hernandez via Gcc-patches wrote:
> > >
> > > > > @@ -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.
> > >
> > > > > + relation_chain **prev = &(m_relations.m_head);
> > > >
> > > > s/[()]//
> > > > thanks,
> > >
> > > There seems to be two other spots where a redundant bitmap_bit_p checks
> > > if we want to bitmap_clear_bit. In dse and ira.
> > > Like:
> > > $ cat ~/coccinelle/gcc_bitmap_bit_p-0.cocci ; echo EOF
> > > // replace redundant bitmap_bit_p() bitmap_clear_bit with the latter
> > > @ rule1 @
> > > identifier fn;
> > > expression bitmap, bit;
> > > @@
> > >
> > > fn(...) {
> > > <...
> > > (
> > > -if (bitmap_bit_p (bitmap, bit))
> > > +if (bitmap_clear_bit (bitmap, bit))
> > > {
> > > ...
> > > - bitmap_clear_bit (bitmap, bit);
> > > ...
> > > }
> > > |
> > > -if (bitmap_bit_p (bitmap, bit))
> > > +if (bitmap_clear_bit (bitmap, bit))
> > > {
> > > ...
> > > }
> > > ...
> > > -bitmap_clear_bit (bitmap, bit);
> > > )
> > > ...>
> > > }
> > > EOF
> > > $ find gcc/ -type f -a \( -name "*.c" -o -name "*.cc" \) -a \( ! -path
> > > "gcc/testsuite/*" -a ! -path "gcc/contrib/*" \) -exec spatch -sp_file
> > > ~/coccinelle/gcc_bitmap_bit_p-0.cocci --show-diff {} \;
> > > diff =
> > > --- gcc/dse.c
> > > +++ /tmp/cocci-output-1104419-443759-dse.c
> > > @@ -3238,9 +3238,8 @@ mark_reachable_blocks (sbitmap unreachab
> > >edge e;
> > >edge_iterator ei;
> > >
> > > - if (bitmap_bit_p (unreachable_blocks, bb->index))
> > > + if (bitmap_clear_bit(unreachable_blocks, bb->index))
> > > {
> > > - bitmap_clear_bit (unreachable_blocks, bb->index);
> > >FOR_EACH_EDGE (e, ei, bb->preds)
> > > {
> > > mark_reachable_blocks (unreachable_blocks, e->src);
> > > diff =
> > > --- gcc/ira.c
> > > +++ /tmp/cocci-output-1104678-d8679a-ira.c
> > > @@ -2944,17 +2944,15 @@ mark_elimination (int from, int to)
> > >FOR_EACH_BB_FN (bb, cfun)
> > > {
> > >r = DF_LR_IN (bb);
> > > - if (bitmap_bit_p (r, from))
> > > + if (bitmap_clear_bit(r, from))
> > > {
> > > - bitmap_clear_bit (r, from);
> > > bitmap_set_bit (r, to);
> > > }
> > >if (! df_live)
> > > continue;
> > >r = DF_LIVE_IN (bb);
> > > - if (bitmap_bit_p (r, from))
> > > + if (bitmap_clear_bit(r, from))
> > > {
> > > - bitmap_clear_bit (r, from);
> > > bitmap_set_bit (r, to);
> > > }
> > > }
> > > # in ira.c one would have to fixup the curly braces manually
> > > PS: coccinelle seems to ruin the spaces before braces in the '+' even
> > > though i have written them correctly according to GNU style..
> > >
> >
>
Re: redundant bitmap_bit_p followed by bitmap_clear_bit [was: Re: [COMMITTED] Kill second order relations in the path solver.]
On Mon, 1 Nov 2021 15:21:03 +0100
Aldy Hernandez wrote:
> I'm not convinced this makes the code clearer to read, especially if
> it's not on a critical path. But if you feel strongly, please submit
> a patch ;-).
No i don't feel strongly about it.
Compiling e.g. -O2 ira.o
# Overhead Samples Command Shared Object Symbol
# ... . .
#
100.00% 4197 cc1plus cc1plus[.] mark_reachable_blocks
100.00% 22000 cc1plus cc1plus[.] path_oracle::killing_def
and the mark_elimination is reload.
So it's not just a handful of calls saved but some. And it would be
smaller code as it saves a call. Well maybe another day.
thanks,
>
> Aldy
>
> On Mon, Nov 1, 2021 at 3:10 PM Bernhard Reutner-Fischer
> wrote:
> >
> > On Thu, 28 Oct 2021 01:55:30 +0200
> > Bernhard Reutner-Fischer wrote:
> >
> > > On Wed, 27 Oct 2021 20:13:21 +0200
> > > Aldy Hernandez via Gcc-patches wrote:
> >
> > > > @@ -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.
> >
> > > > + relation_chain **prev = &(m_relations.m_head);
> > >
> > > s/[()]//
> > > thanks,
> >
> > There seems to be two other spots where a redundant bitmap_bit_p checks
> > if we want to bitmap_clear_bit. In dse and ira.
> > Like:
> > $ cat ~/coccinelle/gcc_bitmap_bit_p-0.cocci ; echo EOF
> > // replace redundant bitmap_bit_p() bitmap_clear_bit with the latter
> > @ rule1 @
> > identifier fn;
> > expression bitmap, bit;
> > @@
> >
> > fn(...) {
> > <...
> > (
> > -if (bitmap_bit_p (bitmap, bit))
> > +if (bitmap_clear_bit (bitmap, bit))
> > {
> > ...
> > - bitmap_clear_bit (bitmap, bit);
> > ...
> > }
> > |
> > -if (bitmap_bit_p (bitmap, bit))
> > +if (bitmap_clear_bit (bitmap, bit))
> > {
> > ...
> > }
> > ...
> > -bitmap_clear_bit (bitmap, bit);
> > )
> > ...>
> > }
> > EOF
> > $ find gcc/ -type f -a \( -name "*.c" -o -name "*.cc" \) -a \( ! -path
> > "gcc/testsuite/*" -a ! -path "gcc/contrib/*" \) -exec spatch -sp_file
> > ~/coccinelle/gcc_bitmap_bit_p-0.cocci --show-diff {} \;
> > diff =
> > --- gcc/dse.c
> > +++ /tmp/cocci-output-1104419-443759-dse.c
> > @@ -3238,9 +3238,8 @@ mark_reachable_blocks (sbitmap unreachab
> >edge e;
> >edge_iterator ei;
> >
> > - if (bitmap_bit_p (unreachable_blocks, bb->index))
> > + if (bitmap_clear_bit(unreachable_blocks, bb->index))
> > {
> > - bitmap_clear_bit (unreachable_blocks, bb->index);
> >FOR_EACH_EDGE (e, ei, bb->preds)
> > {
> > mark_reachable_blocks (unreachable_blocks, e->src);
> > diff =
> > --- gcc/ira.c
> > +++ /tmp/cocci-output-1104678-d8679a-ira.c
> > @@ -2944,17 +2944,15 @@ mark_elimination (int from, int to)
> >FOR_EACH_BB_FN (bb, cfun)
> > {
> >r = DF_LR_IN (bb);
> > - if (bitmap_bit_p (r, from))
> > + if (bitmap_clear_bit(r, from))
> > {
> > - bitmap_clear_bit (r, from);
> > bitmap_set_bit (r, to);
> > }
> >if (! df_live)
> > continue;
> >r = DF_LIVE_IN (bb);
> > - if (bitmap_bit_p (r, from))
> > + if (bitmap_clear_bit(r, from))
> > {
> > - bitmap_clear_bit (r, from);
> > bitmap_set_bit (r, to);
> > }
> > }
> > # in ira.c one would have to fixup the curly braces manually
> > PS: coccinelle seems to ruin the spaces before braces in the '+' even
> > though i have written them correctly according to GNU style..
> >
>
Re: redundant bitmap_bit_p followed by bitmap_clear_bit [was: Re: [COMMITTED] Kill second order relations in the path solver.]
I'm not convinced this makes the code clearer to read, especially if
it's not on a critical path. But if you feel strongly, please submit
a patch ;-).
Aldy
On Mon, Nov 1, 2021 at 3:10 PM Bernhard Reutner-Fischer
wrote:
>
> On Thu, 28 Oct 2021 01:55:30 +0200
> Bernhard Reutner-Fischer wrote:
>
> > On Wed, 27 Oct 2021 20:13:21 +0200
> > Aldy Hernandez via Gcc-patches wrote:
>
> > > @@ -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.
>
> > > + relation_chain **prev = &(m_relations.m_head);
> >
> > s/[()]//
> > thanks,
>
> There seems to be two other spots where a redundant bitmap_bit_p checks
> if we want to bitmap_clear_bit. In dse and ira.
> Like:
> $ cat ~/coccinelle/gcc_bitmap_bit_p-0.cocci ; echo EOF
> // replace redundant bitmap_bit_p() bitmap_clear_bit with the latter
> @ rule1 @
> identifier fn;
> expression bitmap, bit;
> @@
>
> fn(...) {
> <...
> (
> -if (bitmap_bit_p (bitmap, bit))
> +if (bitmap_clear_bit (bitmap, bit))
> {
> ...
> - bitmap_clear_bit (bitmap, bit);
> ...
> }
> |
> -if (bitmap_bit_p (bitmap, bit))
> +if (bitmap_clear_bit (bitmap, bit))
> {
> ...
> }
> ...
> -bitmap_clear_bit (bitmap, bit);
> )
> ...>
> }
> EOF
> $ find gcc/ -type f -a \( -name "*.c" -o -name "*.cc" \) -a \( ! -path
> "gcc/testsuite/*" -a ! -path "gcc/contrib/*" \) -exec spatch -sp_file
> ~/coccinelle/gcc_bitmap_bit_p-0.cocci --show-diff {} \;
> diff =
> --- gcc/dse.c
> +++ /tmp/cocci-output-1104419-443759-dse.c
> @@ -3238,9 +3238,8 @@ mark_reachable_blocks (sbitmap unreachab
>edge e;
>edge_iterator ei;
>
> - if (bitmap_bit_p (unreachable_blocks, bb->index))
> + if (bitmap_clear_bit(unreachable_blocks, bb->index))
> {
> - bitmap_clear_bit (unreachable_blocks, bb->index);
>FOR_EACH_EDGE (e, ei, bb->preds)
> {
> mark_reachable_blocks (unreachable_blocks, e->src);
> diff =
> --- gcc/ira.c
> +++ /tmp/cocci-output-1104678-d8679a-ira.c
> @@ -2944,17 +2944,15 @@ mark_elimination (int from, int to)
>FOR_EACH_BB_FN (bb, cfun)
> {
>r = DF_LR_IN (bb);
> - if (bitmap_bit_p (r, from))
> + if (bitmap_clear_bit(r, from))
> {
> - bitmap_clear_bit (r, from);
> bitmap_set_bit (r, to);
> }
>if (! df_live)
> continue;
>r = DF_LIVE_IN (bb);
> - if (bitmap_bit_p (r, from))
> + if (bitmap_clear_bit(r, from))
> {
> - bitmap_clear_bit (r, from);
> bitmap_set_bit (r, to);
> }
> }
> # in ira.c one would have to fixup the curly braces manually
> PS: coccinelle seems to ruin the spaces before braces in the '+' even
> though i have written them correctly according to GNU style..
>
redundant bitmap_bit_p followed by bitmap_clear_bit [was: Re: [COMMITTED] Kill second order relations in the path solver.]
On Thu, 28 Oct 2021 01:55:30 +0200
Bernhard Reutner-Fischer wrote:
> On Wed, 27 Oct 2021 20:13:21 +0200
> Aldy Hernandez via Gcc-patches wrote:
> > @@ -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.
> > + relation_chain **prev = &(m_relations.m_head);
>
> s/[()]//
> thanks,
There seems to be two other spots where a redundant bitmap_bit_p checks
if we want to bitmap_clear_bit. In dse and ira.
Like:
$ cat ~/coccinelle/gcc_bitmap_bit_p-0.cocci ; echo EOF
// replace redundant bitmap_bit_p() bitmap_clear_bit with the latter
@ rule1 @
identifier fn;
expression bitmap, bit;
@@
fn(...) {
<...
(
-if (bitmap_bit_p (bitmap, bit))
+if (bitmap_clear_bit (bitmap, bit))
{
...
- bitmap_clear_bit (bitmap, bit);
...
}
|
-if (bitmap_bit_p (bitmap, bit))
+if (bitmap_clear_bit (bitmap, bit))
{
...
}
...
-bitmap_clear_bit (bitmap, bit);
)
...>
}
EOF
$ find gcc/ -type f -a \( -name "*.c" -o -name "*.cc" \) -a \( ! -path
"gcc/testsuite/*" -a ! -path "gcc/contrib/*" \) -exec spatch -sp_file
~/coccinelle/gcc_bitmap_bit_p-0.cocci --show-diff {} \;
diff =
--- gcc/dse.c
+++ /tmp/cocci-output-1104419-443759-dse.c
@@ -3238,9 +3238,8 @@ mark_reachable_blocks (sbitmap unreachab
edge e;
edge_iterator ei;
- if (bitmap_bit_p (unreachable_blocks, bb->index))
+ if (bitmap_clear_bit(unreachable_blocks, bb->index))
{
- bitmap_clear_bit (unreachable_blocks, bb->index);
FOR_EACH_EDGE (e, ei, bb->preds)
{
mark_reachable_blocks (unreachable_blocks, e->src);
diff =
--- gcc/ira.c
+++ /tmp/cocci-output-1104678-d8679a-ira.c
@@ -2944,17 +2944,15 @@ mark_elimination (int from, int to)
FOR_EACH_BB_FN (bb, cfun)
{
r = DF_LR_IN (bb);
- if (bitmap_bit_p (r, from))
+ if (bitmap_clear_bit(r, from))
{
- bitmap_clear_bit (r, from);
bitmap_set_bit (r, to);
}
if (! df_live)
continue;
r = DF_LIVE_IN (bb);
- if (bitmap_bit_p (r, from))
+ if (bitmap_clear_bit(r, from))
{
- bitmap_clear_bit (r, from);
bitmap_set_bit (r, to);
}
}
# in ira.c one would have to fixup the curly braces manually
PS: coccinelle seems to ruin the spaces before braces in the '+' even
though i have written them correctly according to GNU style..
