Re: [Patch, i386] Support BMI and BMI2 targets in multiversioning

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Sun, Jan 25, 2015 at 10:37 AM, Uros Bizjak <ubizjak@gmail.com> wrote:
> On Sun, Jan 25, 2015 at 7:23 PM, Uros Bizjak <ubizjak@gmail.com> wrote:
>> On Sat, Jan 24, 2015 at 11:49 AM, Allan Sandfeld Jensen
>> <allan@carewolf.com> wrote:
>>> On Saturday 24 January 2015, Uros Bizjak wrote:
>>>> On Mon, Jan 12, 2015 at 6:02 PM, Uros Bizjak <ubizjak@gmail.com> wrote:
>>>> > Hello!
>>>> >
>>>> >>> On Wed, Dec 31, 2014 at 01:28:47PM +0100, Allan Sandfeld Jensen wrote:
>>>> >>> > I recently wanted to use multiversioning for BMI2 specific extensions
>>>> >>> > PDEP/PEXT, and noticed it wasn't there. So I wrote this patch to add
>>>> >>> > it, and also added AES, F16C and BMI1 for completeness.
>>>> >>>
>>>> >>> AES nor F16C doesn't make any sense IMHO for multiversioning, you need
>>>> >>> special intrinsics for that anyway and when you use them, the function
>>>> >>> will fail to compile without those features.
>>>> >>> Multiversioning only makes sense for ISA features the compiler uses for
>>>> >>> normal C/C++ code without any intrinsics.
>>>> >>
>>>> >> Patch reduced to just adding BMI and BMI2 multiversioning:
>>>> > +2014-12-29  Allan Sandfeld Jensen  <sandfeld@kde.org>
>>>> > +
>>>> > + * config/i386/i386.c (get_builtin_code_for_version): Add
>>>> > + support for BMI and BMI2 multiversion functions.
>>>> >
>>>> > +2014-12-29  Allan Sandfeld Jensen  <sandfeld@kde.org>
>>>> > +
>>>> > + * gcc.target/i386/funcspec-5.c: Test new multiversion targets.
>>>> > + * g++.dg/ext/mv17.C: Test BMI/BMI2 multiversion dispatcher.
>>>> >
>>>> > +2014-12-29  Allan Sandfeld Jensen  <sandfeld@kde.org>
>>>> > +
>>>> > + * config/i386/cpuinfo.c (enum processor_features): Add FEATURE_BMI and
>>>> > + FEATURE_BMI2.
>>>> > + (get_available_features): Detect FEATURE_BMI and FEATURE_BMI2.
>>>> >
>>>> > OK for mainline
>>>>
>>>> Allan, did you commit the patch to mainline? I don't see it in SVN logs.
>>>>
>>>> (If you don't have SVN commit access, please mention it in the patch
>>>> submission, so someone will commit the patch for you).
>>>>
>>> Sorry. I don't have SVN commit access.
>>
>> Committed with a bunch of fixes (e.g. missing fold_builtin_cpu part in
>> gcc/config/i386/i386.c, and mv17.C test didn't compile at all due to
>> missing parenthesis).
>
> ... and now with committed ChangeLog and patch.
>
> gcc/ChangeLog:
>
>     * config/i386/i386.c (get_builtin_code_for_version): Add
>     support for BMI and BMI2 multiversion functions.
>     (fold_builtin_cpu): Add F_BMI and F_BMI2.
>
> libgcc/ChangeLog:
>
>     * config/i386/cpuinfo.c (enum processor_features): Add FEATURE_BMI and
>     FEATURE_BMI2.
>     (get_available_features): Detect FEATURE_BMI and FEATURE_BMI2.
>
> testsuite/ChangeLog:
>
>     * gcc.target/i386/funcspec-5.c: Test new multiversion targets.
>     * g++.dg/ext/mv17.C: Test BMI/BMI2 multiversion dispatcher.
>

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 9ec40cb..441911d 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -34289,15 +34289,18 @@ get_builtin_code_for_version (tree decl, tree *predica
te_list)
     P_PROC_SSE4_A,
     P_SSE4_1,
     P_SSE4_2,
-    P_PROC_SSE4_2,
     P_POPCNT,
+    P_PROC_SSE4_2,
     P_AVX,
     P_PROC_AVX,
+    P_BMI,
+    P_PROC_BMI,
     P_FMA4,
     P_XOP,
     P_PROC_XOP,
     P_FMA,
     P_PROC_FMA,
+    P_BMI2,
     P_AVX2,
     P_PROC_AVX2,
     P_AVX512F,

This changed the priority of P_POPCNT and caused

FAIL: g++.dg/ext/mv1.C  -std=gnu++98 execution test
FAIL: g++.dg/ext/mv1.C  -std=gnu++11 execution test
FAIL: g++.dg/ext/mv1.C  -std=gnu++14 execution test

on Nehalem and Westmere machines:

mv1.exe: /export/gnu/import/git/sources/gcc/gcc/testsuite/g++.dg/ext/mv1.C:51:
int main(): Assertion `val == 5' failed.

since "val" is 6 now.


-- 
H.J.