i965/fs: Add a local common subexpression elimination pass.

Total instructions: 18210 -> 17836
49/163 programs affected (30.1%)
12888 -> 12514 instructions in affected programs (2.9% reduction)

This reduces Lightsmark's "Scale down filter" shader from 395
instructions to 283, a whopping 28%.  It also reduces register pressure
significantly: the SIMD8 program now uses 29 registers instead of 101,
giving us more than enough room for a SIMD16 program.

v2: Add && !inst->conditional_mod to the "skip some instructions" check.

Signed-off-by: Kenneth Graunke <[email protected]>
Reviewed-by: Ian Romanick <[email protected]>
Reviewed-by: Eric Anholt <[email protected]>

0 files changed, 0 insertions, 0 deletions