Mesa (master): freedreno/ir3: add support for a6xx 'merged' register set

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Module: Mesa
Branch: master
Commit: 70bf639328fa00d7875e82b43fb011b0687559c0
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=70bf639328fa00d7875e82b43fb011b0687559c0

Author: Rob Clark <robdclark at gmail.com>
Date:   Sat Aug 11 10:30:38 2018 -0400

freedreno/ir3: add support for a6xx 'merged' register set

Starting with a6xx, half and full precision registers conflict.  Which
makes things a bit more efficient, ie. if some parts of the shader are
heavy on half-precision and others on full precision, you don't have to
allocate the worst case for both.  But it means we need to setup some
additional conflicts.

Signed-off-by: Rob Clark <robdclark at gmail.com>

---

 src/gallium/drivers/freedreno/ir3/ir3.c    |  7 ++++++-
 src/gallium/drivers/freedreno/ir3/ir3_ra.c | 19 ++++++++++++++++++-
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/src/gallium/drivers/freedreno/ir3/ir3.c b/src/gallium/drivers/freedreno/ir3/ir3.c
index d1a73ddc72..3f1216bdaa 100644
--- a/src/gallium/drivers/freedreno/ir3/ir3.c
+++ b/src/gallium/drivers/freedreno/ir3/ir3.c
@@ -115,7 +115,12 @@ static uint32_t reg(struct ir3_register *reg, struct ir3_info *info,
 			/* ignore writes to dummy register r63.x */
 		} else if (max < 48) {
 			if (reg->flags & IR3_REG_HALF) {
-				info->max_half_reg = MAX2(info->max_half_reg, max);
+				if (info->gpu_id >= 600) {
+					/* starting w/ a6xx, half regs conflict with full regs: */
+					info->max_reg = MAX2(info->max_reg, (max+1)/2);
+				} else {
+					info->max_half_reg = MAX2(info->max_half_reg, max);
+				}
 			} else {
 				info->max_reg = MAX2(info->max_reg, max);
 			}
diff --git a/src/gallium/drivers/freedreno/ir3/ir3_ra.c b/src/gallium/drivers/freedreno/ir3/ir3_ra.c
index a1c048c4a1..f6605443e5 100644
--- a/src/gallium/drivers/freedreno/ir3/ir3_ra.c
+++ b/src/gallium/drivers/freedreno/ir3/ir3_ra.c
@@ -285,8 +285,25 @@ ir3_ra_alloc_reg_set(struct ir3_compiler *compiler)
 		}
 	}
 
+	/* starting a6xx, half precision regs conflict w/ full precision regs: */
+	if (compiler->gpu_id >= 600) {
+		/* because of transitivity, we can get away with just setting up
+		 * conflicts between the first class of full and half regs:
+		 */
+		for (unsigned j = 0; j < CLASS_REGS(0) / 2; j++) {
+			unsigned freg  = set->gpr_to_ra_reg[0][j];
+			unsigned hreg0 = set->gpr_to_ra_reg[HALF_OFFSET][(j * 2) + 0];
+			unsigned hreg1 = set->gpr_to_ra_reg[HALF_OFFSET][(j * 2) + 1];
+
+			ra_add_transitive_reg_conflict(set->regs, freg, hreg0);
+			ra_add_transitive_reg_conflict(set->regs, freg, hreg1);
+		}
 
-	ra_set_finalize(set->regs, q_values);
+		// TODO also need to update q_values, but for now:
+		ra_set_finalize(set->regs, NULL);
+	} else {
+		ra_set_finalize(set->regs, q_values);
+	}
 
 	ralloc_free(q_values);