From: Rob Clark <robdclark@chromium.org>
Date: Mon, 27 Jan 2020 16:29:35 +0000 (-0800)
Subject: freedreno/ir3: simplify split from collect
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=752aeb7b3fe75b3c6ce8d9dadaba9c4111fa7254;p=mesa.git

freedreno/ir3: simplify split from collect

In some cases we need to split components out from what was already a
collect.  That was making it hard to DCE unused components of the
collect.  (Ie. unused components of fragcoord, etc)

So just detect this case and skip the chained collect+split.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3569>
---

diff --git a/src/freedreno/ir3/ir3_context.c b/src/freedreno/ir3/ir3_context.c
index 33e73bcb216..b44dc4a67f3 100644
--- a/src/freedreno/ir3/ir3_context.c
+++ b/src/freedreno/ir3/ir3_context.c
@@ -323,6 +323,16 @@ ir3_split_dest(struct ir3_block *block, struct ir3_instruction **dst,
 		return;
 	}
 
+	if (src->opc == OPC_META_COLLECT) {
+		debug_assert((base + n) < src->regs_count);
+
+		for (int i = 0; i < n; i++) {
+			dst[i] = ssa(src->regs[i + base + 1]);
+		}
+
+		return;
+	}
+
 	unsigned flags = dest_flags(src);
 
 	for (int i = 0, j = 0; i < n; i++) {