[Bug target/67310] New: [PATCH] gcc 4.8.4 fails to compile with -march=native on VIA nano CPU

[Bug target/67310] New: [PATCH] gcc 4.8.4 fails to compile with -march=native on VIA nano CPU

[jol_indien at yahoo dot fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67310

            Bug ID: 67310
           Summary: [PATCH] gcc 4.8.4 fails to compile with -march=native
                    on VIA nano CPU
           Product: gcc
           Version: 4.8.4
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jol_indien at yahoo dot fr
  Target Milestone: ---

Created attachment 36234
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36234&action=edit
patch to properly detect VIA nano CPU

GCC 4.8.4 detects VIA nano CPU as a "core2" one and thus fails to compile any
executable when called with "-march=native":
echo 'int main(){return 0;}' > test.c && gcc -march=native  -O2   test.c -o
test && rm test.c test
test.c:1:0: error: CPU you selected does not support x86-64 instruction set
 int main(){return 0;}
 ^

The attached patch properly detects the VIA nano CPU and sets up the proper
compile flags, ie:
 -march=x86-64 -mcx16 -msahf -mno-movbe -mno-aes
 -mno-pclmul -mno-popcnt -mno-abm -mno-lwp -mno-fma -mno-fma4 -mno-xop
 -mno-bmi -mno-bmi2 -mno-tbm -mno-avx -mno-avx2 -msse3 -mssse3 -mno-sse4.2
 -mno-sse4.1 -mno-lzcnt -mno-rtm -mno-hle -mno-rdrnd -mno-f16c
 -mno-fsgsbase -mno-rdseed -mno-prfchw -mno-adx -mfxsr -mno-xsave
 -mno-xsaveopt --param l1-cache-size=64 --param l1-cache-line-size=64
 --param l2-cache-size=1024 -mtune=generic
which enables:  -mcx16 -mfxsr -mmmx -msahf -msse -msse2 -msse3 -mssse3

Of course, this does not give a full support of this CPU family but allows to
compile properly for it.

Tested with:
vendor_id       : CentaurHauls
cpu family      : 6
model           : 15
model name      : VIA Nano processor U2250 (1.6GHz Capable)
stepping        : 3

Please consider to apply this patch.

[Bug target/67310] [PATCH] gcc 4.8.4 fails to compile with -march=native on VIA nano CPU

[jol_indien at yahoo dot fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67310

jol_indien at yahoo dot fr changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #36234|0                           |1
        is obsolete|                            |

--- Comment #1 from jol_indien at yahoo dot fr ---
Created attachment 36239
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36239&action=edit
Minimal patch to properly compile on VIA nano CPU with "-march=native"

[Bug target/67310] [PATCH] gcc 4.8.4 fails to compile with -march=native on VIA nano CPU

[jol_indien at yahoo dot fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67310

--- Comment #2 from jol_indien at yahoo dot fr ---
This new version of the patch is:
* an optimisation, avoiding modifying code that does not need to be
* a bugfix, fixing "nocona" architecture detection

Please consider applying in recent gcc versions.

[Bug target/67310] [PATCH] gcc 4.8.4 fails to compile with -march=native on VIA nano CPU

[jol_indien at yahoo dot fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67310

--- Comment #3 from jol_indien at yahoo dot fr ---
Here are two new patches, one for gcc 4.8.x versions (tested with 4.8.4 &
4.8.5), one for 4.9+ versions (tested with 4.9.3).
This patch is safer, support of VIA Nano based on CPU vendor name instead of
"has_longmode" in the previous one.
The 4.9+ patch also applies for gcc 5.x; unfortunately, for any reason, I
cannot get the "host_detect_local_cpu" function being called with gcc 5.2 as if
-march=native, -mcpu=native and -mtune=native options were ignored by the
compiler.

[Bug target/67310] [PATCH] gcc 4.8.4 fails to compile with -march=native on VIA nano CPU

[jol_indien at yahoo dot fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67310

jol_indien at yahoo dot fr changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #36239|0                           |1
        is obsolete|                            |

--- Comment #4 from jol_indien at yahoo dot fr ---
Created attachment 36244
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36244&action=edit
patch to properly detect VIA nano CPU for gcc 4.8.x versions

[Bug target/67310] [PATCH] gcc 4.8.4 fails to compile with -march=native on VIA nano CPU

[jol_indien at yahoo dot fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67310

--- Comment #5 from jol_indien at yahoo dot fr ---
Created attachment 36245
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36245&action=edit
patch to properly detect VIA nano CPU for gcc 4.9+ versions

[Bug target/67310] [PATCH] gcc 4.8.4 fails to compile with -march=native on VIA nano CPU

[vapier at gentoo dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67310

--- Comment #6 from Mike Frysinger <vapier at gentoo dot org> ---
normally the gcc devs want patches posted to the gcc-patches@gcc.gnu.org
mailing list.  they don't review/comment on patches in bugs.