[llvm-commits] [PATCH] Remove redundant register copies when inserting to Q registers on ARM

[Jakob Stoklund Olesen]

On Sep 3, 2012, at 1:19 AM, James Molloy <James.Molloy at arm.com> wrote:

> Hi Jakob,
> 
> Sure. Please find attached a patch which does just this.
> 
> OK to commit?

Hi James,

This masking code doesn't look right:

+      unsigned DLane = QLane & LaneMask;
+      unsigned DReg = TRI->getSubReg(QReg, ARM::dsub_0 +
+                                     ((QLane >> LaneShift) & LaneMask) );

Please add comments explaining what the various lanes and masks do.

/jakob