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Re: [PATCH, i386] PR 57927: -march=core-avx2 different than -march=native on INTEL Haswell (i7-4700K)


On Tue, 27 Aug 2013 19:41:09 +0200
Uros Bizjak <ubizjak@gmail.com> wrote:

> On Tue, Aug 27, 2013 at 7:36 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> 
> >>> As reported in [1] the host processor detection has not yet been updated
> >>> to recognize Intel Ivy Bridge and Haswell processors.
> >>> This small patch adds the detection of these processors and assumes
> >>> core-avx2 as march for unknown processors of the PENTIUMPRO family that
> >>> support AVX2.
> >>
> >> I have committed slightly improved (attached) patch that uses
> >> core-avx-i for IvyBridge and adds another IvyBridge model number.
> >> While there, I also reordered a bunch  of statements.
> >>
> >> Thanks,
> >> Uros.
> >
> > Page C-3 in ntel optimization guide shows:
> >
> > 06_3CH, 06_45H, 06_46H Intel microarchitecture Haswell
> > 06_3AH, 06_3EH Intel microarchitecture Ivy Bridge
> > 06_2AH, 06_2DH Intel microarchitecture Sandy Bridge
> > 06_25H, 06_2CH, 06_2FH Intel microarchitecture Westmere
> > 06_1AH, 06_1EH, 06_1FH, Intel microarchitecture Nehalem
> > 06_2EH
> > 06_17H, 06_1DH Enhanced Intel Core microarchitecture
> > 06_0FH Intel Core microarchitecture
> >
> > At least, we should add 0x45 and 0x46 to Haswell.
> 
> OK, the patch is pre-approved.

Can these changes be backported to 4.8 and the Ivy Bridge parts to 4.7 as
well? We've had a couple reports of bad -march=native results for Haswell on
4.7.  I can file PRs if you're interested.


-- 
Ryan Hill                        psn: dirtyepic_sk
   gcc-porting/toolchain/wxwidgets @ gentoo.org

47C3 6D62 4864 0E49 8E9E  7F92 ED38 BD49 957A 8463

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