GBE: Fix register liveness issue under simd mode.

GBE: Fix register liveness issue under simd mode.

As we run in SIMD mode with prediction mask to indicate active lanes,
If a vreg is defined in a loop, and there are som uses of the vreg out of the loop,
the define point may be run several times under *different* prediction mask.
For these kinds of vreg, we must extend the vreg liveness into the whole loop.
If we don't do this, it's liveness is killed before the def point inside loop.
If the vreg's corresponding physical reg is assigned to other vreg during the
killed period, and the instructions before kill point were re-executed with different prediction,
the inactive lanes of vreg maybe over-written. Then the out-of-loop use will got wrong data.

This patch fixes the HaarFixture case in opencv.

Signed-off-by: Ruiling Song <ruiling.song@intel.com>
Reviewed-by: Zhigang Gong <zhigang.gong@linux.intel.com>