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* [Bug target/58523] New: ARM and AArch64: -fsection-anchors doesn't seem to work
@ 2013-09-25 6:20 b.grayson at samsung dot com
2013-09-25 6:28 ` [Bug target/58523] " pinskia at gcc dot gnu.org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: b.grayson at samsung dot com @ 2013-09-25 6:20 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58523
Bug ID: 58523
Summary: ARM and AArch64: -fsection-anchors doesn't seem to
work
Product: gcc
Version: 4.9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: b.grayson at samsung dot com
Target: arm, aarch64
Build: gcc-4.9-20130915-arm-linux-gnueabhihf,
gcc-aarch64-4.9-20130602/aarch64-linux-gnu-gcc
Created attachment 30890
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30890&action=edit
Test C file with two global variables, and a use of both of them
I've tried compiling with -fsection-anchors in several different releases of
gcc for ARM and now for aarch64, and it seems the optimization is not kicking
in for scenarios where it should. I looked through the gcc/config directories,
and the support seems to be there. Here is a simple testcase. The resulting
assembly (not posted here, according to bug-reporting guidelines) does a full
address-generation for variable a, and then again for variable b.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug target/58523] ARM and AArch64: -fsection-anchors doesn't seem to work
2013-09-25 6:20 [Bug target/58523] New: ARM and AArch64: -fsection-anchors doesn't seem to work b.grayson at samsung dot com
@ 2013-09-25 6:28 ` pinskia at gcc dot gnu.org
2013-09-25 6:29 ` pinskia at gcc dot gnu.org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2013-09-25 6:28 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58523
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution|--- |INVALID
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
It is due to them being common symbols which are never section anchored due to
they might be in another TU.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug target/58523] ARM and AArch64: -fsection-anchors doesn't seem to work
2013-09-25 6:20 [Bug target/58523] New: ARM and AArch64: -fsection-anchors doesn't seem to work b.grayson at samsung dot com
2013-09-25 6:28 ` [Bug target/58523] " pinskia at gcc dot gnu.org
@ 2013-09-25 6:29 ` pinskia at gcc dot gnu.org
2013-09-25 6:30 ` pinskia at gcc dot gnu.org
2013-09-25 6:55 ` b.grayson at samsung dot com
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2013-09-25 6:29 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58523
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #1)
> It is due to them being common symbols which are never section anchored due
> to they might be in another TU.
Use -fno-common or initialize those variables to 0.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug target/58523] ARM and AArch64: -fsection-anchors doesn't seem to work
2013-09-25 6:20 [Bug target/58523] New: ARM and AArch64: -fsection-anchors doesn't seem to work b.grayson at samsung dot com
2013-09-25 6:28 ` [Bug target/58523] " pinskia at gcc dot gnu.org
2013-09-25 6:29 ` pinskia at gcc dot gnu.org
@ 2013-09-25 6:30 ` pinskia at gcc dot gnu.org
2013-09-25 6:55 ` b.grayson at samsung dot com
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2013-09-25 6:30 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58523
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
With -fno-common,
arm LE produces:
movw r3, #:lower16:.LANCHOR0
movt r3, #:upper16:.LANCHOR0
ldmia r3, {r0, r3}
add r0, r0, r3
bx lr
AARCH64 produces:
adrp x1, .LANCHOR0
add x1, x1, :lo12:.LANCHOR0
ldr w2, [x1]
ldr w0, [x1,4]
add w0, w2, w0
ret
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug target/58523] ARM and AArch64: -fsection-anchors doesn't seem to work
2013-09-25 6:20 [Bug target/58523] New: ARM and AArch64: -fsection-anchors doesn't seem to work b.grayson at samsung dot com
` (2 preceding siblings ...)
2013-09-25 6:30 ` pinskia at gcc dot gnu.org
@ 2013-09-25 6:55 ` b.grayson at samsung dot com
3 siblings, 0 replies; 5+ messages in thread
From: b.grayson at samsung dot com @ 2013-09-25 6:55 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58523
Brian Grayson <b.grayson at samsung dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|RESOLVED |CLOSED
--- Comment #4 from Brian Grayson <b.grayson at samsung dot com> ---
Thanks for the rapid response. That does the trick, both in my testcase, and
in my larger program.
^ permalink raw reply [flat|nested] 5+ messages in thread
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2013-09-25 6:20 [Bug target/58523] New: ARM and AArch64: -fsection-anchors doesn't seem to work b.grayson at samsung dot com
2013-09-25 6:28 ` [Bug target/58523] " pinskia at gcc dot gnu.org
2013-09-25 6:29 ` pinskia at gcc dot gnu.org
2013-09-25 6:30 ` pinskia at gcc dot gnu.org
2013-09-25 6:55 ` b.grayson at samsung dot com
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