[Bug target/21397] New: -march selects wrong arm_tune flags

[Bug target/21397] New: -march selects wrong arm_tune flags

[trauscher at loytec dot com]

When using -march, wrong tuning flags are selected.
E.g., -march=armv4t selects 'tune_flags' for arm600, instead of
arm7tdmi (or similar). The error is in arm_override_options().

When "-march" is given, (sel - all_architectures) is calculated.
In contrast, "-mcpu" calculates (sel -  all_cores). This
array index is stored in 'arm_tune' (arm.c:791)

In arm.c:909 tune_flags are always taken from all_cores so 
that the calculated index references the wrong array when
using "-march"

tune_flags = all_cores[(int)arm_tune].flags;

-- 
           Summary: -march selects wrong arm_tune flags
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: target
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: trauscher at loytec dot com
                CC: gcc-bugs at gcc dot gnu dot org
  GCC host triplet: i386-linux
GCC target triplet: arm-*-elf


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21397

[Bug target/21397] -march selects wrong arm_tune flags

[rearnsha at gcc dot gnu dot org]

------- Additional Comments From rearnsha at gcc dot gnu dot org  2005-05-08 23:47 -------
The -march flag is not supposed to alter the tuning.  Use -mtune or -mcpu, as
appropriate, if you want to do that.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21397

[Bug target/21397] -march selects wrong arm_tune flags

[trauscher at loytec dot com]

------- Additional Comments From trauscher at loytec dot com  2005-05-09 07:04 -------
The problem is that -march=xxx -mtune=yyy doesn't work.
The arm_override_option function scans the options
in the order -mtune, -march, -mcpu. So when -mtune is
given, 'arm_tune' first set by -mtune and then
overwritten with the wrong tune settings from -march.

I think, this problem was introduced between gcc-3.4.3 and
gcc-4.0.0. In 3.4.3 only -mtune sets 'arm_tune' where in
4.0.0 all three flags affect 'arm_tune'.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |UNCONFIRMED
         Resolution|INVALID                     |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21397

[Bug target/21397] arm: -march overrides -mtune

[rearnsha at gcc dot gnu dot org]

------- Additional Comments From rearnsha at gcc dot gnu dot org  2005-05-09 11:18 -------
Ah! I understand now.  Sorry, your initial report wasn't clear.  Yes, I agree
this is incorrect.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2005-05-09 11:18:37
               date|                            |
            Summary|-march selects wrong        |arm: -march overrides -mtune
                   |arm_tune flags              |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21397

[Bug target/21397] [4.0/4.1 regression] arm: -march overrides -mtune

[rearnsha at gcc dot gnu dot org]

------- Additional Comments From rearnsha at gcc dot gnu dot org  2005-05-09 14:04 -------
This is, of course, a regression from 3.4.x



-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |rearnsha at gcc dot gnu dot
                   |dot org                     |org
             Status|NEW                         |ASSIGNED
            Summary|arm: -march overrides -mtune|[4.0/4.1 regression] arm: -
                   |                            |march overrides -mtune


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21397

[Bug target/21397] [4.0/4.1 regression] arm: -march overrides -mtune

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2005-05-09 14:20 -------
Subject: Bug 21397

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	rearnsha@gcc.gnu.org	2005-05-09 14:15:51

Modified files:
	gcc            : ChangeLog 
	gcc/config/arm : arm.c 

Log message:
	PR target/21397
	* arm.c (ARM_OPT_SET_CPU, ARM_OPT_SET_ARCH, ARM_OPT_SET_TUNE): Define.
	(arm_override_options): Use them instead of manifest constants.  Don't
	allow -march to override the -mtune setting.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&r1=2.8670&r2=2.8671
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/config/arm/arm.c.diff?cvsroot=gcc&r1=1.451&r2=1.452



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21397

[Bug target/21397] [4.0/4.1 regression] arm: -march overrides -mtune

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2005-05-09 14:53 -------
Subject: Bug 21397

CVSROOT:	/cvs/gcc
Module name:	gcc
Branch: 	gcc-4_0-branch
Changes by:	rearnsha@gcc.gnu.org	2005-05-09 14:53:20

Modified files:
	gcc            : ChangeLog 
	gcc/config/arm : arm.c 

Log message:
	PR target/21397
	* arm.c (ARM_OPT_SET_CPU, ARM_OPT_SET_ARCH, ARM_OPT_SET_TUNE): Define.
	(arm_override_options): Use them instead of manifest constants.  Don't
	allow -march to override the -mtune setting.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=2.7592.2.232&r2=2.7592.2.233
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/config/arm/arm.c.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.430.2.1&r2=1.430.2.2



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21397

[Bug target/21397] [4.0/4.1 regression] arm: -march overrides -mtune

[rearnsha at gcc dot gnu dot org]

------- Additional Comments From rearnsha at gcc dot gnu dot org  2005-05-09 15:04 -------
fixed

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.0.1


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21397