i965: set size of txf_mcs payload vgrf properly

Previously we left the size of this vgrf as 1, which caused register
allocation to be subtly broken. If we were lucky we would explode in
the post-alloc instruction scheduler; if we were unlucky we'd just stomp
on someone else and get broken rendering.

Fixes crash when running `tesseract` with the following settings:

   msaa 4
   glineardepth 0

Also fixes the piglit test:

  arb_sample_shading-builtin-gl-sample-id

Signed-off-by: Chris Forbes <chrisf@ijw.co.nz>
Cc: Anuj Phogat <anuj.phogat@gmail.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=72859
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

diff --git a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
index 8e516a5812b2ea3c8b1153f6b0dea090a92a40c0..53cd0a1cf57bc216b3145b9c2f5aaaa276332464 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
@@ -1549,6 +1549,7 @@ fs_visitor::emit_mcs_fetch(ir_texture *ir, fs_reg coordinate, int sampler)
    }
 
    fs_inst *inst = emit(SHADER_OPCODE_TXF_MCS, dest, payload);
+   virtual_grf_sizes[payload.reg] = next.reg_offset;
    inst->base_mrf = -1;
    inst->mlen = next.reg_offset * reg_width;
    inst->header_present = false;