Mesa (master): freedreno/ir3: insert extra move into phi

[Rob Clark]

Module: Mesa
Branch: master
Commit: 506b561ba7e3df2a7759dded684fae84bf459f65
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=506b561ba7e3df2a7759dded684fae84bf459f65

Author: Rob Clark <robclark at freedesktop.org>
Date:   Tue Apr  5 13:45:34 2016 -0400

freedreno/ir3: insert extra move into phi

We had an implicit assumption that the phi src was assigned in it's
source (pred) block leading into the phi.  But this is not true with
NIR, so we can't just ignore the source block specified in the
nir_phi_src.  Insert an extra mov in the source block.  If it is not
required the CP pass will take it back out again.

Fixes:

  ./tests/spec/glsl-1.10/execution/vs-call-in-nested-loop.shader_test
  ./tests/spec/glsl-1.10/execution/vs-inner-loop-modifies-outer-loop-var.shader_test

and probably others.

Signed-off-by: Rob Clark <robclark at freedesktop.org>

---

 src/gallium/drivers/freedreno/ir3/ir3_compiler_nir.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/gallium/drivers/freedreno/ir3/ir3_compiler_nir.c b/src/gallium/drivers/freedreno/ir3/ir3_compiler_nir.c
index 3f14412..245b61f 100644
--- a/src/gallium/drivers/freedreno/ir3/ir3_compiler_nir.c
+++ b/src/gallium/drivers/freedreno/ir3/ir3_compiler_nir.c
@@ -1661,6 +1661,16 @@ resolve_phis(struct ir3_compile *ctx, struct ir3_block *block)
 
 		foreach_list_typed(nir_phi_src, nsrc, node, &nphi->srcs) {
 			struct ir3_instruction *src = get_src(ctx, &nsrc->src)[0];
+
+			/* NOTE: src might not be in the same block as it comes from
+			 * according to the phi.. but in the end the backend assumes
+			 * it will be able to assign the same register to each (which
+			 * only works if it is assigned in the src block), so insert
+			 * an extra mov to make sure the phi src is assigned in the
+			 * block it comes from:
+			 */
+			src = ir3_MOV(get_block(ctx, nsrc->pred), src, TYPE_U32);
+
 			ir3_reg_create(instr, 0, IR3_REG_SSA)->instr = src;
 		}
 	}