i965/vec4: Eliminate writes that are never read.
authorMatt Turner <mattst88@gmail.com>
Tue, 11 Mar 2014 20:16:37 +0000 (13:16 -0700)
committerMatt Turner <mattst88@gmail.com>
Mon, 24 Mar 2014 18:06:26 +0000 (11:06 -0700)
commit9cd51bb0c4608258199c69bc7738e72f055799d2
treeec2a160a77dab3b2e573c39859927ac3bfda4c10
parent1b8f143a2302739de90cb643d732e12b55d4e4eb
i965/vec4: Eliminate writes that are never read.

With an awful O(n^2) algorithm that searches previous instructions for
dead writes.

total instructions in shared programs: 805582 -> 788074 (-2.17%)
instructions in affected programs:     144561 -> 127053 (-12.11%)

Reviewed-by: Eric Anholt <eric@anholt.net>
src/mesa/drivers/dri/i965/brw_vec4.cpp