From 33a700be91be8adbcaf480c22e2eb4319ed29159 Mon Sep 17 00:00:00 2001
From: Jose Maria Casanova Crespo <jmcasanova@igalia.com>
Date: Sat, 7 Feb 2026 18:28:19 +0100
Subject: [PATCH] broadcom/compiler: hardware-accelerated 4x8-bit dot products
 on V3D 7.1+

VIR instructions and nir_to_vir implementation of 4x8-bit dot products
using native HW accelerated ALU instructions.

setnnmode instructions are marked as having side effects.

Assisted-by: Claude Opus 4.6
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/41255>
---
 src/broadcom/compiler/nir_to_vir.c   | 18 ++++++++++++++++++
 src/broadcom/compiler/v3d_compiler.h |  7 +++++++
 src/broadcom/compiler/vir.c          |  4 ++++
 3 files changed, 29 insertions(+)

diff --git a/src/broadcom/compiler/nir_to_vir.c b/src/broadcom/compiler/nir_to_vir.c
index 5db99c2e3f6..13e5d88fb82 100644
--- a/src/broadcom/compiler/nir_to_vir.c
+++ b/src/broadcom/compiler/nir_to_vir.c
@@ -1829,6 +1829,24 @@ ntq_emit_alu(struct v3d_compile *c, nir_alu_instr *instr)
                 vir_set_unpack(c->defs[result.index], 0, V3D71_QPU_UNPACK_MAX0);
                 break;
 
+        case nir_op_udot_4x8_uadd:
+                assert(c->devinfo->ver >= 71);
+                vir_SETNNMODE_UU(c);
+                result = vir_ADD(c, vir_V8DOT(c, src[0], src[1]), src[2]);
+                break;
+
+        case nir_op_sdot_4x8_iadd:
+                assert(c->devinfo->ver >= 71);
+                vir_SETNNMODE_SS(c);
+                result = vir_ADD(c, vir_V8DOT(c, src[0], src[1]), src[2]);
+                break;
+
+        case nir_op_sudot_4x8_iadd:
+                assert(c->devinfo->ver >= 71);
+                vir_SETNNMODE_SU(c);
+                result = vir_ADD(c, vir_V8DOT(c, src[0], src[1]), src[2]);
+                break;
+
         default:
                 mesa_loge("Unknown NIR ALU inst: %s",
                           nir_instr_as_str(&instr->instr, NULL));
diff --git a/src/broadcom/compiler/v3d_compiler.h b/src/broadcom/compiler/v3d_compiler.h
index c1e290744a5..0b6ebeae86d 100644
--- a/src/broadcom/compiler/v3d_compiler.h
+++ b/src/broadcom/compiler/v3d_compiler.h
@@ -1506,6 +1506,13 @@ VIR_M_ALU1(FUNPACKSNORMHI)
 VIR_M_ALU1(VFTOUNORM10LO)
 VIR_M_ALU1(VFTOUNORM10HI)
 
+/* V3D 7.1 v8dot and its signedness configuration */
+VIR_M_ALU2(V8DOT)
+VIR_A_NODST_0(SETNNMODE_UU)
+VIR_A_NODST_0(SETNNMODE_SU)
+VIR_A_NODST_0(SETNNMODE_US)
+VIR_A_NODST_0(SETNNMODE_SS)
+
 static inline struct qinst *
 vir_MOV_cond(struct v3d_compile *c, enum v3d_qpu_cond cond,
              struct qreg dest, struct qreg src)
diff --git a/src/broadcom/compiler/vir.c b/src/broadcom/compiler/vir.c
index ca06b450e14..d2c3615b7a2 100644
--- a/src/broadcom/compiler/vir.c
+++ b/src/broadcom/compiler/vir.c
@@ -65,6 +65,10 @@ vir_has_side_effects(struct v3d_compile *c, struct qinst *inst)
                 case V3D_QPU_A_STVPMP:
                 case V3D_QPU_A_VPMWT:
                 case V3D_QPU_A_TMUWT:
+                case V3D_QPU_A_SETNNMODE_UU:
+                case V3D_QPU_A_SETNNMODE_SU:
+                case V3D_QPU_A_SETNNMODE_US:
+                case V3D_QPU_A_SETNNMODE_SS:
                         return true;
                 default:
                         break;