Mesa (master): freedreno/ir3: fix grouping issue w/ reverse swizzles

[Rob Clark]

Module: Mesa
Branch: master
Commit: 77a9107bf299faa738737ed105c1b5e5ac06d1ca
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=77a9107bf299faa738737ed105c1b5e5ac06d1ca

Author: Rob Clark <robclark at freedesktop.org>
Date:   Mon Apr 18 11:32:40 2016 -0400

freedreno/ir3: fix grouping issue w/ reverse swizzles

When we have something like:

   MOV OUT[n], IN[m].wzyx

the existing grouping code was missing a potential conflict.  Due to
input needing to be sequential scalar regs, we have:

 IN:  x <-> y <-> z <-> w

which would be grouped to:

 OUT: w <-> z2 <-> y2 <-> x  (where the 2 denotes a copy/mov)

but that can't actually work.  We need to realize that x and w are
already in the same chain, not just that they aren't both already in
new chain being built.

With this fixed, we probably no longer need the hack from f68f6c0.

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

---

 src/gallium/drivers/freedreno/ir3/ir3_group.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/src/gallium/drivers/freedreno/ir3/ir3_group.c b/src/gallium/drivers/freedreno/ir3/ir3_group.c
index cd59080..f229fe6 100644
--- a/src/gallium/drivers/freedreno/ir3/ir3_group.c
+++ b/src/gallium/drivers/freedreno/ir3/ir3_group.c
@@ -90,6 +90,22 @@ instr_insert_mov(void *arr, int idx, struct ir3_instruction *instr)
 }
 static struct group_ops instr_ops = { instr_get, instr_insert_mov };
 
+/* verify that cur != instr, but cur is also not in instr's neighbor-list: */
+static bool
+in_neighbor_list(struct ir3_instruction *instr, struct ir3_instruction *cur)
+{
+	if (!instr)
+		return false;
+
+	if (instr == cur)
+		return true;
+
+	for (instr = ir3_neighbor_first(instr); instr; instr = instr->cp.right)
+		if (instr == cur)
+			return true;
+
+	return false;
+}
 
 static void
 group_n(struct group_ops *ops, void *arr, unsigned n)
@@ -121,7 +137,7 @@ restart:
 
 			/* we also can't have an instr twice in the group: */
 			for (j = i + 1; (j < n) && !conflict; j++)
-				if (ops->get(arr, j) == instr)
+				if (in_neighbor_list(ops->get(arr, j), instr))
 					conflict = true;
 
 			if (conflict) {