[Bug middle-end/45274] __restrict__ type qualifier does not work on pointers to bitfields

2020-01-14 Thread pinskia at gcc dot gnu.org 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=45274

Andrew Pinski  changed:

   What|Removed |Added

   Assignee|rguenth at gcc dot gnu.org |pinskia at gcc dot 
gnu.org

--- Comment #5 from Andrew Pinski  ---
Mine.  With my bit-field lowering and a patch to reassociation to some handle
BIT_INSERT optimizations, we are able to optimize this to just load/store.

[Bug middle-end/45274] __restrict__ type qualifier does not work on pointers to bitfields

2016-06-29 Thread rguenth at gcc dot gnu.org 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=45274

Richard Biener  changed:

   What|Removed |Added

 Status|NEW |ASSIGNED
   Assignee|unassigned at gcc dot gnu.org  |rguenth at gcc dot 
gnu.org

--- Comment #4 from Richard Biener  ---
The alias-set issue doesn't occur since quite some time (it's using alias-set 1
for me).  Also restrict is working.

GCC 6 optimizes this on x86_64 to

foo:
.LFB0:
.cfi_startproc
movzbl  (%rdi), %edx
movzbl  (%rsi), %eax
movl%edx, %r8d
movl%edx, %ecx
andl$-4, %eax
andl$1, %r8d
andl$2, %ecx
orl %r8d, %eax
orl %ecx, %eax
movl%edx, %ecx
andl$8, %edx
andl$4, %ecx
andl$-13, %eax
orl %ecx, %eax
orl %edx, %eax
movb%al, (%rsi)
movl(%rdi), %eax
andl$-16, %eax
movl%eax, %edx
movl(%rsi), %eax
andl$15, %eax
orl %edx, %eax
movl%eax, (%rsi)
ret

thus it is doing a good job in piecewise copying of the struct.  It doesn't
detect that it can simply use a 32bit load/store.  But there are duplicates
in bugzilla for that issue.

Interestingly with some bitfield lowering work plus some match.pd hackery
I get that:

foo:
.LFB0:
.cfi_startproc
movl(%rdi), %eax
movl%eax, (%rsi)
ret

whee.

[Bug middle-end/45274] __restrict__ type qualifier does not work on pointers to bitfields

2011-04-11 Thread pinskia at gcc dot gnu.org 
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45274

Andrew Pinski pinskia at gcc dot gnu.org changed:

   What|Removed |Added

   Keywords||missed-optimization
 Target|powerpc64-unknown-linux-gnu |
   |, mips64-elf|

--- Comment #3 from Andrew Pinski pinskia at gcc dot gnu.org 2011-04-11 
20:13:25 UTC ---
(In reply to comment #1)
 I don't think this has anything to do with restrict and all with lowering
 bitfield accesses only during expansion, and at RTL level the bitfield
 operations being too big for combiner to optimize them.

No this is unrelated to the combiner not be able to optimize the bitfield
accesses.  Rather it is related to how store and loads happen on bitfields. We
don't try to keep track of individual bits for a change in the store.

[Bug middle-end/45274] __restrict__ type qualifier does not work on pointers to bitfields

2010-10-28 Thread pinskia at gcc dot gnu.org 
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45274

Andrew Pinski pinskia at gcc dot gnu.org changed:

   What|Removed |Added

 Target|powerpc64-unknown-linux-gnu |powerpc64-unknown-linux-gnu
   ||, mips64-elf
 Status|UNCONFIRMED |NEW
   Last reconfirmed||2010.10.28 20:05:42
 Ever Confirmed|0   |1

--- Comment #2 from Andrew Pinski pinskia at gcc dot gnu.org 2010-10-28 
20:05:42 UTC ---
Expand has the issue:

(insn 7 6 8 t2.c:7 (set (reg:SI 197)
(mem/s:SI (reg/v/f:DI 193 [ src ]) [0 S4 A32])) -1 (nil))

Notice the aliasing set of 0.

Confirmed.

[Bug middle-end/45274] __restrict__ type qualifier does not work on pointers to bitfields

2010-08-13 Thread jakub at gcc dot gnu dot org 


--- Comment #1 from jakub at gcc dot gnu dot org  2010-08-13 08:01 ---
I don't think this has anything to do with restrict and all with lowering
bitfield accesses only during expansion, and at RTL level the bitfield
operations being too big for combiner to optimize them.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45274