[PATCH] D32002: [X86] Improve large struct pass by value performance

[Zvi Rackover via Phabricator via llvm-commits]

zvi added a comment.

This LGTM, thanks!
Maybe better wait for other reviewers to give the final ok.



================
Comment at: lib/Target/X86/X86.td:508
   FeatureBMI2,
+  FeatureFastString,
   FeatureFMA,
----------------
courbet wrote:
> zvi wrote:
> > courbet wrote:
> > > RKSimon wrote:
> > > > Is this a Haswell feature in particular or the only target that has been tested?
> > > I've tested it on Haswell and Skylake. The Skylake model below actually uses HSWFeatures too, so I have not added it there again.
> > The Optimization Guide section @craig.topper  quoted above states that this feature is available starting from Ivy Bridge.
> Unfortunately I don't have an IvyBridge to measure it. Do we want to blindly trust the manual ? :)
I have no objection for limiting to Haswell and later.


https://reviews.llvm.org/D32002