neon mlal qs8 rsum use addw instead of mlal

- remove vone which was being lengthened with mlal and then multiplied by the input - use sliced accumulators for 16 bit accumulation - rename functions from neon_mlal to neon_addw - add const to mask variable in remainder handler for addw and neondot microkernels PiperOrigin-RevId: 635029345
umadevimcw · May 18, 2024 · fcb3669 · fcb3669
1 parent aee04e1
commit fcb3669
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Showing 23 changed files with 335 additions and 321 deletions.
diff --git a/bench/qs8-rsum-minmax-fp32.cc b/bench/qs8-rsum-minmax-fp32.cc
@@ -38,8 +38,8 @@ BENCHMARK_CAPTURE(qs8_rsum, scalar_imagic_u4,
   ->UseRealTime();
 
 #if XNN_ARCH_ARM || XNN_ARCH_ARM64
-  BENCHMARK_CAPTURE(qs8_rsum, neon_mlal_u16,
-                    xnn_qs8_rsum_minmax_fp32_ukernel__neon_mlal_u16,
+  BENCHMARK_CAPTURE(qs8_rsum, neon_addw_u16,
+                    xnn_qs8_rsum_minmax_fp32_ukernel__neon_addw_u16,
                     xnn_init_qs8_avgpool_minmax_fp32_neon_params,
                     benchmark::utils::CheckNEON)
     ->Apply(BenchmarkRSUM)
@@ -48,8 +48,8 @@ BENCHMARK_CAPTURE(qs8_rsum, scalar_imagic_u4,
 
 
 #if XNN_ARCH_ARM || XNN_ARCH_ARM64
-  BENCHMARK_CAPTURE(qs8_rsum, neon_mlal_u32,
-                    xnn_qs8_rsum_minmax_fp32_ukernel__neon_mlal_u32,
+  BENCHMARK_CAPTURE(qs8_rsum, neon_addw_u32,
+                    xnn_qs8_rsum_minmax_fp32_ukernel__neon_addw_u32,
                     xnn_init_qs8_avgpool_minmax_fp32_neon_params,
                     benchmark::utils::CheckNEON)
     ->Apply(BenchmarkRSUM)
@@ -58,8 +58,8 @@ BENCHMARK_CAPTURE(qs8_rsum, scalar_imagic_u4,
 
 
 #if XNN_ARCH_ARM || XNN_ARCH_ARM64
-  BENCHMARK_CAPTURE(qs8_rsum, neon_mlal_u64,
-                    xnn_qs8_rsum_minmax_fp32_ukernel__neon_mlal_u64,
+  BENCHMARK_CAPTURE(qs8_rsum, neon_addw_u64,
+                    xnn_qs8_rsum_minmax_fp32_ukernel__neon_addw_u64,
                     xnn_init_qs8_avgpool_minmax_fp32_neon_params,
                     benchmark::utils::CheckNEON)
     ->Apply(BenchmarkRSUM)
@@ -68,8 +68,8 @@ BENCHMARK_CAPTURE(qs8_rsum, scalar_imagic_u4,
 
 
 #if XNN_ARCH_ARM || XNN_ARCH_ARM64
-  BENCHMARK_CAPTURE(qs8_rsum, neon_mlal_u16_acc2,
-                    xnn_qs8_rsum_minmax_fp32_ukernel__neon_mlal_u16_acc2,
+  BENCHMARK_CAPTURE(qs8_rsum, neon_addw_u16_acc2,
+                    xnn_qs8_rsum_minmax_fp32_ukernel__neon_addw_u16_acc2,
                     xnn_init_qs8_avgpool_minmax_fp32_neon_params,
                     benchmark::utils::CheckNEON)
     ->Apply(BenchmarkRSUM)
@@ -78,8 +78,8 @@ BENCHMARK_CAPTURE(qs8_rsum, scalar_imagic_u4,
 
 
 #if XNN_ARCH_ARM || XNN_ARCH_ARM64
-  BENCHMARK_CAPTURE(qs8_rsum, neon_mlal_u32_acc2,
-                    xnn_qs8_rsum_minmax_fp32_ukernel__neon_mlal_u32_acc2,
+  BENCHMARK_CAPTURE(qs8_rsum, neon_addw_u32_acc2,
+                    xnn_qs8_rsum_minmax_fp32_ukernel__neon_addw_u32_acc2,
                     xnn_init_qs8_avgpool_minmax_fp32_neon_params,
                     benchmark::utils::CheckNEON)
     ->Apply(BenchmarkRSUM)
@@ -88,8 +88,8 @@ BENCHMARK_CAPTURE(qs8_rsum, scalar_imagic_u4,
 
 
 #if XNN_ARCH_ARM || XNN_ARCH_ARM64
-  BENCHMARK_CAPTURE(qs8_rsum, neon_mlal_u64_acc2,
-                    xnn_qs8_rsum_minmax_fp32_ukernel__neon_mlal_u64_acc2,
+  BENCHMARK_CAPTURE(qs8_rsum, neon_addw_u64_acc2,
+                    xnn_qs8_rsum_minmax_fp32_ukernel__neon_addw_u64_acc2,
                     xnn_init_qs8_avgpool_minmax_fp32_neon_params,
                     benchmark::utils::CheckNEON)
     ->Apply(BenchmarkRSUM)
@@ -98,8 +98,8 @@ BENCHMARK_CAPTURE(qs8_rsum, scalar_imagic_u4,
 
 
 #if XNN_ARCH_ARM || XNN_ARCH_ARM64
-  BENCHMARK_CAPTURE(qs8_rsum, neon_mlal_u32_acc4,
-                    xnn_qs8_rsum_minmax_fp32_ukernel__neon_mlal_u32_acc4,
+  BENCHMARK_CAPTURE(qs8_rsum, neon_addw_u32_acc4,
+                    xnn_qs8_rsum_minmax_fp32_ukernel__neon_addw_u32_acc4,
                     xnn_init_qs8_avgpool_minmax_fp32_neon_params,
                     benchmark::utils::CheckNEON)
     ->Apply(BenchmarkRSUM)
@@ -108,8 +108,8 @@ BENCHMARK_CAPTURE(qs8_rsum, scalar_imagic_u4,
 
 
 #if XNN_ARCH_ARM || XNN_ARCH_ARM64
-  BENCHMARK_CAPTURE(qs8_rsum, neon_mlal_u64_acc4,
-                    xnn_qs8_rsum_minmax_fp32_ukernel__neon_mlal_u64_acc4,
+  BENCHMARK_CAPTURE(qs8_rsum, neon_addw_u64_acc4,
+                    xnn_qs8_rsum_minmax_fp32_ukernel__neon_addw_u64_acc4,
                     xnn_init_qs8_avgpool_minmax_fp32_neon_params,
                     benchmark::utils::CheckNEON)
     ->Apply(BenchmarkRSUM)

diff --git a/cmake/gen/neon_microkernels.cmake b/cmake/gen/neon_microkernels.cmake
@@ -684,14 +684,14 @@ SET(ALL_NEON_MICROKERNEL_SRCS
   src/qs8-requantization/qs8-requantization-rndna-neon.c
   src/qs8-requantization/qs8-requantization-rndnu-neon-mull.c
   src/qs8-requantization/qs8-requantization-rndnu-neon-qdmulh.c
-  src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-u16-acc2.c
-  src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-u16.c
-  src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-u32-acc2.c
-  src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-u32-acc4.c
-  src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-u32.c
-  src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-u64-acc2.c
-  src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-u64-acc4.c
-  src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-u64.c
+  src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-addw-u16-acc2.c
+  src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-addw-u16.c
+  src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-addw-u32-acc2.c
+  src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-addw-u32-acc4.c
+  src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-addw-u32.c
+  src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-addw-u64-acc2.c
+  src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-addw-u64-acc4.c
+  src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-addw-u64.c
   src/qs8-vadd/gen/qs8-vadd-minmax-neon-ld64-u8.c
   src/qs8-vadd/gen/qs8-vadd-minmax-neon-ld64-u16.c
   src/qs8-vadd/gen/qs8-vadd-minmax-neon-ld64-u24.c

diff --git a/gen/neon_microkernels.bzl b/gen/neon_microkernels.bzl
@@ -680,14 +680,14 @@ ALL_NEON_MICROKERNEL_SRCS = [
     "src/qs8-requantization/qs8-requantization-rndna-neon.c",
     "src/qs8-requantization/qs8-requantization-rndnu-neon-mull.c",
     "src/qs8-requantization/qs8-requantization-rndnu-neon-qdmulh.c",
-    "src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-u16-acc2.c",
-    "src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-u16.c",
-    "src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-u32-acc2.c",
-    "src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-u32-acc4.c",
-    "src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-u32.c",
-    "src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-u64-acc2.c",
-    "src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-u64-acc4.c",
-    "src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-u64.c",
+    "src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-addw-u16-acc2.c",
+    "src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-addw-u16.c",
+    "src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-addw-u32-acc2.c",
+    "src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-addw-u32-acc4.c",
+    "src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-addw-u32.c",
+    "src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-addw-u64-acc2.c",
+    "src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-addw-u64-acc4.c",
+    "src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-addw-u64.c",
     "src/qs8-vadd/gen/qs8-vadd-minmax-neon-ld64-u8.c",
     "src/qs8-vadd/gen/qs8-vadd-minmax-neon-ld64-u16.c",
     "src/qs8-vadd/gen/qs8-vadd-minmax-neon-ld64-u24.c",

diff --git a/scripts/generate-qs8-rsum.sh b/scripts/generate-qs8-rsum.sh
@@ -10,16 +10,16 @@ tools/xngen src/qs8-rsum/scalar.c.in -D CHANNEL_TILE=2 -D ACCUMULATORS=1 -D REQU
 tools/xngen src/qs8-rsum/scalar.c.in -D CHANNEL_TILE=4 -D ACCUMULATORS=1 -D REQUANTIZATION=FP32 -D VARIANT=IMAGIC -D WASM=0 -o src/qs8-rsum/gen/qs8-rdsum-minmax-fp32-scalar-imagic-u4-acc1.c &
 
 ################################## ARM NEON ###################################
-tools/xngen src/qs8-rsum/neon-mlal.c.in -D ACCUMULATORS=1 -D CHANNEL_TILE=16  -D REQUANTIZATION=FP32 -D ARMV8=0 -o src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-u16.c &
-tools/xngen src/qs8-rsum/neon-mlal.c.in -D ACCUMULATORS=1 -D CHANNEL_TILE=32  -D REQUANTIZATION=FP32 -D ARMV8=0 -o src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-u32.c &
-tools/xngen src/qs8-rsum/neon-mlal.c.in -D ACCUMULATORS=1 -D CHANNEL_TILE=64  -D REQUANTIZATION=FP32 -D ARMV8=0 -o src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-u64.c &
+tools/xngen src/qs8-rsum/neon-addw.c.in -D ACCUMULATORS=1 -D CHANNEL_TILE=16  -D REQUANTIZATION=FP32 -D ARMV8=0 -o src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-addw-u16.c &
+tools/xngen src/qs8-rsum/neon-addw.c.in -D ACCUMULATORS=1 -D CHANNEL_TILE=32  -D REQUANTIZATION=FP32 -D ARMV8=0 -o src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-addw-u32.c &
+tools/xngen src/qs8-rsum/neon-addw.c.in -D ACCUMULATORS=1 -D CHANNEL_TILE=64  -D REQUANTIZATION=FP32 -D ARMV8=0 -o src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-addw-u64.c &
 
-tools/xngen src/qs8-rsum/neon-mlal.c.in -D ACCUMULATORS=2 -D CHANNEL_TILE=16  -D REQUANTIZATION=FP32 -D ARMV8=0 -o src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-u16-acc2.c &
-tools/xngen src/qs8-rsum/neon-mlal.c.in -D ACCUMULATORS=2 -D CHANNEL_TILE=32  -D REQUANTIZATION=FP32 -D ARMV8=0 -o src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-u32-acc2.c &
-tools/xngen src/qs8-rsum/neon-mlal.c.in -D ACCUMULATORS=2 -D CHANNEL_TILE=64  -D REQUANTIZATION=FP32 -D ARMV8=0 -o src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-u64-acc2.c &
+tools/xngen src/qs8-rsum/neon-addw.c.in -D ACCUMULATORS=2 -D CHANNEL_TILE=16  -D REQUANTIZATION=FP32 -D ARMV8=0 -o src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-addw-u16-acc2.c &
+tools/xngen src/qs8-rsum/neon-addw.c.in -D ACCUMULATORS=2 -D CHANNEL_TILE=32  -D REQUANTIZATION=FP32 -D ARMV8=0 -o src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-addw-u32-acc2.c &
+tools/xngen src/qs8-rsum/neon-addw.c.in -D ACCUMULATORS=2 -D CHANNEL_TILE=64  -D REQUANTIZATION=FP32 -D ARMV8=0 -o src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-addw-u64-acc2.c &
 
-tools/xngen src/qs8-rsum/neon-mlal.c.in -D ACCUMULATORS=4 -D CHANNEL_TILE=32  -D REQUANTIZATION=FP32 -D ARMV8=0 -o src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-u32-acc4.c &
-tools/xngen src/qs8-rsum/neon-mlal.c.in -D ACCUMULATORS=4 -D CHANNEL_TILE=64  -D REQUANTIZATION=FP32 -D ARMV8=0 -o src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-u64-acc4.c &
+tools/xngen src/qs8-rsum/neon-addw.c.in -D ACCUMULATORS=4 -D CHANNEL_TILE=32  -D REQUANTIZATION=FP32 -D ARMV8=0 -o src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-addw-u32-acc4.c &
+tools/xngen src/qs8-rsum/neon-addw.c.in -D ACCUMULATORS=4 -D CHANNEL_TILE=64  -D REQUANTIZATION=FP32 -D ARMV8=0 -o src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neon-addw-u64-acc4.c &
 
 tools/xngen src/qs8-rsum/neondot.c.in -D ACCUMULATORS=1 -D CHANNEL_TILE=16  -D REQUANTIZATION=FP32 -o src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neondot-u16.c &
 tools/xngen src/qs8-rsum/neondot.c.in -D ACCUMULATORS=1 -D CHANNEL_TILE=32  -D REQUANTIZATION=FP32 -o src/qs8-rsum/gen/qs8-rsum-minmax-fp32-neondot-u32.c &

diff --git a/.../gen/qs8-rsum-minmax-fp32-neon-u16-acc2.c → ...qs8-rsum-minmax-fp32-neon-addw-u16-acc2.c b/.../gen/qs8-rsum-minmax-fp32-neon-u16-acc2.c → ...qs8-rsum-minmax-fp32-neon-addw-u16-acc2.c
@@ -1,5 +1,5 @@
 // Auto-generated file. Do not edit!
-//   Template: src/qs8-rsum/neon-mlal.c.in
+//   Template: src/qs8-rsum/neon-addw.c.in
 //   Generator: tools/xngen
 //
 // Copyright 2024 Google LLC
@@ -15,7 +15,7 @@
 #include <xnnpack/math.h>
 #include <xnnpack/reduce.h>
 
-void xnn_qs8_rsum_minmax_fp32_ukernel__neon_mlal_u16_acc2(
+void xnn_qs8_rsum_minmax_fp32_ukernel__neon_addw_u16_acc2(
     size_t batch,
     const int8_t* input,
     int8_t* output,
@@ -25,7 +25,8 @@ void xnn_qs8_rsum_minmax_fp32_ukernel__neon_mlal_u16_acc2(
   assert(input != NULL);
   assert(output != NULL);
 
-  int8x8_t vone = vdup_n_s8(1);
+  // 256 int8s may be summed into an int16 before overflowing.
+  // There are 8 lanes in the accumulator register and 2 registers.
   int num_batches = batch  >> 9;
   int32x4_t vacc0 = vmovq_n_s32(0);
   int32x4_t vacc1 = vmovq_n_s32(0);
@@ -36,8 +37,8 @@ void xnn_qs8_rsum_minmax_fp32_ukernel__neon_mlal_u16_acc2(
       const int8x8_t vt0 = vld1_s8(input); input += 8;
       const int8x8_t vt1 = vld1_s8(input); input += 8;
 
-      vacc16_0 = vmlal_s8(vacc16_0, vt0, vone);
-      vacc16_1 = vmlal_s8(vacc16_1, vt1, vone);
+      vacc16_0 = vaddw_s8(vacc16_0, vt0);
+      vacc16_1 = vaddw_s8(vacc16_1, vt1);
     }
     vacc0 = vaddq_s32(vacc0, vaddq_s32(vmovl_s16(vget_low_s16(vacc16_0)), vmovl_s16(vget_high_s16(vacc16_0))));
     vacc1 = vaddq_s32(vacc1, vaddq_s32(vmovl_s16(vget_low_s16(vacc16_1)), vmovl_s16(vget_high_s16(vacc16_1))));
@@ -49,18 +50,18 @@ void xnn_qs8_rsum_minmax_fp32_ukernel__neon_mlal_u16_acc2(
     for (; batch >= 16; batch -= 16) {
       const int8x8_t vt0 = vld1_s8(input); input += 8;
       const int8x8_t vt1 = vld1_s8(input); input += 8;
-      vacc16_0 = vmlal_s8(vacc16_0, vt0, vone);
-      vacc16_1 = vmlal_s8(vacc16_1, vt1, vone);
+      vacc16_0 = vaddw_s8(vacc16_0, vt0);
+      vacc16_1 = vaddw_s8(vacc16_1, vt1);
     }
     vacc16_0 = vaddq_s16(vacc16_0, vacc16_1);
     for (; batch >= 8; batch -= 8) {
       const int8x8_t vt = vld1_s8(input); input += 8;
-      vacc16_0 = vmlal_s8(vacc16_0, vt, vone);
+      vacc16_0 = vaddw_s8(vacc16_0, vt);
     }
     if (XNN_UNLIKELY(batch != 0)) {
-      int8x8_t vt = vld1_s8(input);
-      vone = vld1_s8(&params->fp32_neon.mask_table[15 - batch]);
-      vacc16_0 = vmlal_s8(vacc16_0, vt, vone);
+      const int8x8_t vt = vld1_s8(input);
+      const int8x8_t vmask = vld1_s8(&params->fp32_neon.mask_table[15 - batch]);
+      vacc16_0 = vmlal_s8(vacc16_0, vt, vmask);
     }
     vacc0 = vaddq_s32(vacc0, vaddq_s32(vmovl_s16(vget_low_s16(vacc16_0)), vmovl_s16(vget_high_s16(vacc16_0))));
   }

diff --git a/...-rsum/gen/qs8-rsum-minmax-fp32-neon-u16.c → .../gen/qs8-rsum-minmax-fp32-neon-addw-u16.c b/...-rsum/gen/qs8-rsum-minmax-fp32-neon-u16.c → .../gen/qs8-rsum-minmax-fp32-neon-addw-u16.c
@@ -1,5 +1,5 @@
 // Auto-generated file. Do not edit!
-//   Template: src/qs8-rsum/neon-mlal.c.in
+//   Template: src/qs8-rsum/neon-addw.c.in
 //   Generator: tools/xngen
 //
 // Copyright 2024 Google LLC
@@ -15,7 +15,7 @@
 #include <xnnpack/math.h>
 #include <xnnpack/reduce.h>
 
-void xnn_qs8_rsum_minmax_fp32_ukernel__neon_mlal_u16(
+void xnn_qs8_rsum_minmax_fp32_ukernel__neon_addw_u16(
     size_t batch,
     const int8_t* input,
     int8_t* output,
@@ -25,7 +25,8 @@ void xnn_qs8_rsum_minmax_fp32_ukernel__neon_mlal_u16(
   assert(input != NULL);
   assert(output != NULL);
 
-  int8x8_t vone = vdup_n_s8(1);
+  // 256 int8s may be summed into an int16 before overflowing.
+  // There are 8 lanes in the accumulator register and 1 registers.
   int num_batches = batch  >> 8;
   int32x4_t vacc0 = vmovq_n_s32(0);
   for (; num_batches > 0; --num_batches) {
@@ -34,8 +35,8 @@ void xnn_qs8_rsum_minmax_fp32_ukernel__neon_mlal_u16(
       const int8x8_t vt0 = vld1_s8(input); input += 8;
       const int8x8_t vt1 = vld1_s8(input); input += 8;
 
-      vacc16_0 = vmlal_s8(vacc16_0, vt0, vone);
-      vacc16_0 = vmlal_s8(vacc16_0, vt1, vone);
+      vacc16_0 = vaddw_s8(vacc16_0, vt0);
+      vacc16_0 = vaddw_s8(vacc16_0, vt1);
     }
     vacc0 = vaddq_s32(vacc0, vaddq_s32(vmovl_s16(vget_low_s16(vacc16_0)), vmovl_s16(vget_high_s16(vacc16_0))));
     batch -= 256;
@@ -45,17 +46,17 @@ void xnn_qs8_rsum_minmax_fp32_ukernel__neon_mlal_u16(
     for (; batch >= 16; batch -= 16) {
       const int8x8_t vt0 = vld1_s8(input); input += 8;
       const int8x8_t vt1 = vld1_s8(input); input += 8;
-      vacc16_0 = vmlal_s8(vacc16_0, vt0, vone);
-      vacc16_0 = vmlal_s8(vacc16_0, vt1, vone);
+      vacc16_0 = vaddw_s8(vacc16_0, vt0);
+      vacc16_0 = vaddw_s8(vacc16_0, vt1);
     }
     for (; batch >= 8; batch -= 8) {
       const int8x8_t vt = vld1_s8(input); input += 8;
-      vacc16_0 = vmlal_s8(vacc16_0, vt, vone);
+      vacc16_0 = vaddw_s8(vacc16_0, vt);
     }
     if (XNN_UNLIKELY(batch != 0)) {
-      int8x8_t vt = vld1_s8(input);
-      vone = vld1_s8(&params->fp32_neon.mask_table[15 - batch]);
-      vacc16_0 = vmlal_s8(vacc16_0, vt, vone);
+      const int8x8_t vt = vld1_s8(input);
+      const int8x8_t vmask = vld1_s8(&params->fp32_neon.mask_table[15 - batch]);
+      vacc16_0 = vmlal_s8(vacc16_0, vt, vmask);
     }
     vacc0 = vaddq_s32(vacc0, vaddq_s32(vmovl_s16(vget_low_s16(vacc16_0)), vmovl_s16(vget_high_s16(vacc16_0))));
   }

diff --git a/.../gen/qs8-rsum-minmax-fp32-neon-u32-acc2.c → ...qs8-rsum-minmax-fp32-neon-addw-u32-acc2.c b/.../gen/qs8-rsum-minmax-fp32-neon-u32-acc2.c → ...qs8-rsum-minmax-fp32-neon-addw-u32-acc2.c
@@ -1,5 +1,5 @@
 // Auto-generated file. Do not edit!
-//   Template: src/qs8-rsum/neon-mlal.c.in
+//   Template: src/qs8-rsum/neon-addw.c.in
 //   Generator: tools/xngen
 //
 // Copyright 2024 Google LLC
@@ -15,7 +15,7 @@
 #include <xnnpack/math.h>
 #include <xnnpack/reduce.h>
 
-void xnn_qs8_rsum_minmax_fp32_ukernel__neon_mlal_u32_acc2(
+void xnn_qs8_rsum_minmax_fp32_ukernel__neon_addw_u32_acc2(
     size_t batch,
     const int8_t* input,
     int8_t* output,
@@ -25,7 +25,8 @@ void xnn_qs8_rsum_minmax_fp32_ukernel__neon_mlal_u32_acc2(
   assert(input != NULL);
   assert(output != NULL);
 
-  int8x8_t vone = vdup_n_s8(1);
+  // 256 int8s may be summed into an int16 before overflowing.
+  // There are 8 lanes in the accumulator register and 2 registers.
   int num_batches = batch  >> 9;
   int32x4_t vacc0 = vmovq_n_s32(0);
   int32x4_t vacc1 = vmovq_n_s32(0);
@@ -38,10 +39,10 @@ void xnn_qs8_rsum_minmax_fp32_ukernel__neon_mlal_u32_acc2(
       const int8x8_t vt2 = vld1_s8(input); input += 8;
       const int8x8_t vt3 = vld1_s8(input); input += 8;
 
-      vacc16_0 = vmlal_s8(vacc16_0, vt0, vone);
-      vacc16_1 = vmlal_s8(vacc16_1, vt1, vone);
-      vacc16_0 = vmlal_s8(vacc16_0, vt2, vone);
-      vacc16_1 = vmlal_s8(vacc16_1, vt3, vone);
+      vacc16_0 = vaddw_s8(vacc16_0, vt0);
+      vacc16_1 = vaddw_s8(vacc16_1, vt1);
+      vacc16_0 = vaddw_s8(vacc16_0, vt2);
+      vacc16_1 = vaddw_s8(vacc16_1, vt3);
     }
     vacc0 = vaddq_s32(vacc0, vaddq_s32(vmovl_s16(vget_low_s16(vacc16_0)), vmovl_s16(vget_high_s16(vacc16_0))));
     vacc1 = vaddq_s32(vacc1, vaddq_s32(vmovl_s16(vget_low_s16(vacc16_1)), vmovl_s16(vget_high_s16(vacc16_1))));
@@ -55,20 +56,20 @@ void xnn_qs8_rsum_minmax_fp32_ukernel__neon_mlal_u32_acc2(
       const int8x8_t vt1 = vld1_s8(input); input += 8;
       const int8x8_t vt2 = vld1_s8(input); input += 8;
       const int8x8_t vt3 = vld1_s8(input); input += 8;
-      vacc16_0 = vmlal_s8(vacc16_0, vt0, vone);
-      vacc16_1 = vmlal_s8(vacc16_1, vt1, vone);
-      vacc16_0 = vmlal_s8(vacc16_0, vt2, vone);
-      vacc16_1 = vmlal_s8(vacc16_1, vt3, vone);
+      vacc16_0 = vaddw_s8(vacc16_0, vt0);
+      vacc16_1 = vaddw_s8(vacc16_1, vt1);
+      vacc16_0 = vaddw_s8(vacc16_0, vt2);
+      vacc16_1 = vaddw_s8(vacc16_1, vt3);
     }
     vacc16_0 = vaddq_s16(vacc16_0, vacc16_1);
     for (; batch >= 8; batch -= 8) {
       const int8x8_t vt = vld1_s8(input); input += 8;
-      vacc16_0 = vmlal_s8(vacc16_0, vt, vone);
+      vacc16_0 = vaddw_s8(vacc16_0, vt);
     }
     if (XNN_UNLIKELY(batch != 0)) {
-      int8x8_t vt = vld1_s8(input);
-      vone = vld1_s8(&params->fp32_neon.mask_table[15 - batch]);
-      vacc16_0 = vmlal_s8(vacc16_0, vt, vone);
+      const int8x8_t vt = vld1_s8(input);
+      const int8x8_t vmask = vld1_s8(&params->fp32_neon.mask_table[15 - batch]);
+      vacc16_0 = vmlal_s8(vacc16_0, vt, vmask);
     }
     vacc0 = vaddq_s32(vacc0, vaddq_s32(vmovl_s16(vget_low_s16(vacc16_0)), vmovl_s16(vget_high_s16(vacc16_0))));
   }