[Bug middle-end/23985] New: [ARM] Wrong code generation with -O2

[Bug middle-end/23985] New: [ARM] Wrong code generation with -O2

[raj dot khem at gmail dot com]

GCC 3.4.3 and 3.4.4 generated wrong code at -O2 and -Os opt level for the
attached testcase. If I user -O1 the test case works fine.

Secondly it also works fine if I specify -O2 -fno-if-convertion2

Thirdly If I comment out

newinfo->fig->shape = *&shape;

line in the testcase it works fine agains.

The testcase can be compile and linked and runtime outputs should match

correct output should be 1
alpha.style = 1
correct output should be 2
alpha.style = 2

in wrong code case. It prints.

correct output should be 1
alpha.style = 254
correct output should be 2
alpha.style = 2

The testcase works fine with GCC 4.0 and CVS Trunk GCC

-- 
           Summary: [ARM] Wrong code generation with -O2
           Product: gcc
           Version: 3.4.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: raj dot khem at gmail dot com
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: arm-unknown-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23985

[Bug middle-end/23985] [ARM] Wrong code generation with -O2

[raj dot khem at gmail dot com]

------- Additional Comments From raj dot khem at gmail dot com  2005-09-20 19:31 -------
Created an attachment (id=9782)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=9782&action=view)
Failing testcase


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23985

[Bug rtl-optimization/23985] [ARM] Wrong code generation with -O2

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|middle-end                  |rtl-optimization
           Keywords|                            |wrong-code


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23985

[Bug middle-end/23985] [ARM] Wrong code generation with -O2

[raj dot khem at gmail dot com]

------- Additional Comments From raj dot khem at gmail dot com  2005-09-20 19:37 -------
It fails on GCC 3.3.1 similarily.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|rtl-optimization            |middle-end
           Keywords|wrong-code                  |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23985

[Bug rtl-optimization/23985] [ARM] Wrong code generation with -O2

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|middle-end                  |rtl-optimization
           Keywords|                            |wrong-code
      Known to fail|                            |3.3.1 3.4.3


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23985

[Bug rtl-optimization/23985] [ARM] Wrong code generation with -O2

[rearnsha at gcc dot gnu dot org]

------- Additional Comments From rearnsha at gcc dot gnu dot org  2005-09-30 10:13 -------
Confirmed by visual inspection of the assembly code.

What seems to be happening is this:

After if conversion we have (pseudo code)

a ? alpha.style = 1
a ? ...
!a ? alpha.style = 2
!a ? ...

inlined_memcpy(newinfo->fig->alpha, alpha, sizeof (alpha)

and this is transformed by the scheduler into 

a ? alpha.style = 1
a ? ...
!a ? ...
inlined_memcpy(newinfo->fig->alpha, alpha, sizeof (alpha))
!a ? alpha.style = 2

That is, alpha.style is only set to 2 after alpha has been copied elsewhere.

Disabling sched-2 also avoids the problem.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
      Known to fail|3.3.1 3.4.3                 |3.3.1 3.4.3 3.4.5
   Last reconfirmed|0000-00-00 00:00:00         |2005-09-30 10:13:03
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23985

[Bug rtl-optimization/23985] [3.4 regression] Memory aliasing information incorrect in inlined memcpy

[rearnsha at gcc dot gnu dot org]

------- Additional Comments From rearnsha at gcc dot gnu dot org  2005-09-30 10:58 -------
testing a fix

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |rearnsha at gcc dot gnu dot
                   |dot org                     |org
             Status|NEW                         |ASSIGNED
            Summary|[ARM] Wrong code generation |[3.4 regression] Memory
                   |with -O2                    |aliasing information
                   |                            |incorrect in inlined memcpy


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23985

[Bug target/23985] [3.4 regression] Memory aliasing information incorrect in inlined memcpy

[rearnsha at gcc dot gnu dot org]

------- Additional Comments From rearnsha at gcc dot gnu dot org  2005-09-30 10:59 -------
This is a bug in the arm backend.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|rtl-optimization            |target


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23985

[Bug target/23985] [3.4 regression] Memory aliasing information incorrect in inlined memcpy

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2005-10-01 13:31 -------
Subject: Bug 23985

CVSROOT:	/cvs/gcc
Module name:	gcc
Branch: 	gcc-3_4-branch
Changes by:	rearnsha@gcc.gnu.org	2005-10-01 13:31:39

Modified files:
	gcc            : ChangeLog 
	gcc/config/arm : arm-protos.h arm.c arm.md 

Log message:
	PR target/23985
	Back-port 2004-08-19  Richard Henderson  <rth@redhat.com>
	* config/arm/arm.c (arm_gen_load_multiple): Use
	adjust_automodify_address.  Take base memory and offset instead
	of unchanging/struct/scalar bits.
	(arm_gen_store_multiple): Likewise.
	(arm_gen_movstrqi): Use adjust_automodify_address.
	* config/arm/arm-protos.h: Update decls.
	* config/arm/arm.md (load_multiple): Update arm_gen_load_multiple call.
	(store_multiple): Similarly.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&only_with_tag=gcc-3_4-branch&r1=2.2326.2.918&r2=2.2326.2.919
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/config/arm/arm-protos.h.diff?cvsroot=gcc&only_with_tag=gcc-3_4-branch&r1=1.61.4.1&r2=1.61.4.2
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/config/arm/arm.c.diff?cvsroot=gcc&only_with_tag=gcc-3_4-branch&r1=1.317.4.9&r2=1.317.4.10
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/config/arm/arm.md.diff?cvsroot=gcc&only_with_tag=gcc-3_4-branch&r1=1.154.4.3&r2=1.154.4.4



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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23985

[Bug target/23985] [3.4 regression] Memory aliasing information incorrect in inlined memcpy

[rearnsha at gcc dot gnu dot org]

------- Additional Comments From rearnsha at gcc dot gnu dot org  2005-10-01 13:33 -------
Fixed.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |3.4.5


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23985