Previously, if we had a .z or .w component that could be compacted
to .y, we'd could overlook that opportunity.
Signed-off-by: Rob Clark <robdcl...@gmail.com>
---
src/compiler/nir/nir_linking_helpers.c | 30 ++++++++++++++++++++------
1 file changed, 23 insertions(+), 7 deletions(-)
diff --git a/src/compiler/nir/nir_linking_helpers.c
b/src/compiler/nir/nir_linking_helpers.c
index 1ab9c095657..ce368a3c132 100644
--- a/src/compiler/nir/nir_linking_helpers.c
+++ b/src/compiler/nir/nir_linking_helpers.c
@@ -431,12 +431,30 @@ compact_components(nir_shader *producer, nir_shader
*consumer, uint8_t *comps,
uint8_t interp = get_interp_type(var, type, default_to_smooth_interp);
for (; cursor[interp] < 32; cursor[interp]++) {
uint8_t cursor_used_comps = comps[cursor[interp]];
+ uint8_t unused_comps = ~cursor_used_comps;
- /* We couldn't find anywhere to pack the varying continue on. */
- if (cursor[interp] == location &&
- (var->data.location_frac == 0 ||
- cursor_used_comps & ((1 << (var->data.location_frac)) - 1)))
- break;
+ /* Don't search beyond our current location, we are just trying
+ * to pack later varyings to lower positions:
+ */
+ if (cursor[interp] == location) {
+ if (var->data.location_frac == 0)
+ break;
+
+ /* If not already aligned to slot, see if we can shift it up.
+ * Note that if we get this far it is a scalar so we know that
+ * shifting this var to any other open position won't conflict
+ * with it's current position.
+ */
+ unsigned p = ffs(unused_comps & 0xf);
+ if (!p)
+ break;
+
+ /* ffs returns 1 for bit zero: */
+ p--;
+
+ if (p >= var->data.location_frac)
+ break;
+ }
/* We can only pack varyings with matching interpolation types */
if (interp_type[cursor[interp]] != interp)
@@ -460,8 +478,6 @@ compact_components(nir_shader *producer, nir_shader
*consumer, uint8_t *comps,
if (!cursor_used_comps)
continue;
- uint8_t unused_comps = ~cursor_used_comps;
-
for (unsigned i = 0; i < 4; i++) {
uint8_t new_var_comps = 1 << i;
if (unused_comps & new_var_comps) {
--
2.19.2
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