metal : fix null-pipeline crash for F16 src1 mul_mat/mul_mat_id (#25648)

* metal : fail closed on mul_mat shapes with missing F16 kernels

* metal : abort on nil pipeline in encoder_set_pipeline

* metal : address review comments

* metal : share mul_mat mm dispatch with supports_op

ggml/src/ggml-metal/ggml-metal-common.cpp

@@ -1,10 +1,27 @@
 #include "ggml-metal-common.h"
 
+#include "ggml.h"
 #include "ggml-impl.h"
 #include "ggml-backend-impl.h"
 
 #include <vector>
 
+bool ggml_metal_op_mul_mat_use_mm(const struct ggml_tensor * op, bool has_simdgroup_mm) {
+    const int64_t ne00 = op->src[0]->ne[0];
+    const int64_t ne11 = op->src[1]->ne[1];
+
+    return !ggml_is_transposed(op->src[0]) &&
+           !ggml_is_transposed(op->src[1]) &&
+           has_simdgroup_mm && ne00 >= 64 && ne11 > 8;
+}
+
+bool ggml_metal_op_mul_mat_id_use_mm(const struct ggml_tensor * op, bool has_simdgroup_mm) {
+    const int64_t ne00 = op->src[0]->ne[0];
+    const int64_t ne21 = op->src[2]->ne[1];
+
+    return has_simdgroup_mm && ne00 >= 64 && ne21 >= 32;
+}
+
 // represents a memory range (i.e. an interval from a starting address p0 to an ending address p1 in a given buffer pb)
 // the type indicates whether it is a source range (i.e. ops read data from it) or a destination range (i.e. ops write data to it)
 struct ggml_mem_range {

ggml/src/ggml-metal/ggml-metal-common.h

@@ -47,6 +47,10 @@ bool ggml_mem_ranges_check(ggml_mem_ranges_t mrs, const struct ggml_tensor * ten
 //       if it proves to work well, we can start using it for other backends in the future
 void ggml_graph_optimize(struct ggml_cgraph * gf);
 
+// mat-mat vs mat-vec dispatch; used by both supports_op and ggml_metal_op_mul_mat*
+bool ggml_metal_op_mul_mat_use_mm   (const struct ggml_tensor * op, bool has_simdgroup_mm);
+bool ggml_metal_op_mul_mat_id_use_mm(const struct ggml_tensor * op, bool has_simdgroup_mm);
+
 #ifdef __cplusplus
 }
 #endif

ggml/src/ggml-metal/ggml-metal-device.m

@@ -3,6 +3,7 @@
 #import "ggml-impl.h"
 #import "ggml-backend-impl.h"
 #import "ggml-metal-impl.h"
+#import "ggml-metal-common.h"
 
 #include <Foundation/Foundation.h>
 
@@ -788,6 +789,10 @@ void ggml_metal_encoder_debug_group_pop (ggml_metal_encoder_t encoder) {
 }
 
 void ggml_metal_encoder_set_pipeline(ggml_metal_encoder_t encoder, struct ggml_metal_pipeline_with_params pipeline) {
+    if (!pipeline.pipeline) {
+        GGML_ABORT("%s: nil Metal pipeline (missing kernel; see compile_pipeline log above)\n", __func__);
+    }
+
     [encoder->obj setComputePipelineState:pipeline.pipeline->obj];
 }
 
@@ -1410,6 +1415,30 @@ void ggml_metal_device_get_memory(ggml_metal_device_t dev, size_t * free, size_t
     }
 }
 
+static bool ggml_metal_supports_mul_mat_op(
+        bool has_simdgroup_reduction,
+        const struct ggml_tensor * op,
+        bool src0_f16_has_mv,
+        bool mm_path) {
+    if (!has_simdgroup_reduction || op->src[0]->type == GGML_TYPE_NVFP4) {
+        return false;
+    }
+
+    if (op->src[1]->type != GGML_TYPE_F16) {
+        return true;
+    }
+
+    if (op->src[0]->type == GGML_TYPE_BF16) {
+        return false;
+    }
+
+    if (src0_f16_has_mv && op->src[0]->type == GGML_TYPE_F16) {
+        return true;
+    }
+
+    return mm_path;
+}
+
 bool ggml_metal_device_supports_op(ggml_metal_device_t dev, const struct ggml_tensor * op) {
     const bool has_simdgroup_mm        = dev->props.has_simdgroup_mm;
     const bool has_simdgroup_reduction = dev->props.has_simdgroup_reduction;
@@ -1713,9 +1742,15 @@ bool ggml_metal_device_supports_op(ggml_metal_device_t dev, const struct ggml_te
         case GGML_OP_GATED_DELTA_NET:
             return has_simdgroup_reduction && op->src[2]->ne[0] % 32 == 0;
         case GGML_OP_SOLVE_TRI:
+            return has_simdgroup_reduction && op->src[0]->type == GGML_TYPE_F32;
         case GGML_OP_MUL_MAT:
+            return ggml_metal_supports_mul_mat_op(
+                    has_simdgroup_reduction, op, true,
+                    ggml_metal_op_mul_mat_use_mm(op, has_simdgroup_mm));
         case GGML_OP_MUL_MAT_ID:
-            return has_simdgroup_reduction && op->src[0]->type != GGML_TYPE_NVFP4;
+            return ggml_metal_supports_mul_mat_op(
+                    has_simdgroup_reduction, op, false,
+                    ggml_metal_op_mul_mat_id_use_mm(op, has_simdgroup_mm));
         case GGML_OP_SET:
         case GGML_OP_CPY:
         case GGML_OP_DUP:

ggml/src/ggml-metal/ggml-metal-ops.cpp

@@ -2362,10 +2362,6 @@ int ggml_metal_op_mul_mat(ggml_metal_op_t ctx, int idx) {
     const int16_t r2 = ne12/ne02;
     const int16_t r3 = ne13/ne03;
 
-    // find the break-even point where the matrix-matrix kernel becomes more efficient compared
-    // to the matrix-vector kernel
-    const int ne11_mm_min = 8;
-
     // first try to use small-batch mat-mv kernels
     // these should be efficient for BS [2, ~8]
     if (op->src[1]->type == GGML_TYPE_F32 && (ne00%128 == 0) &&
@@ -2468,12 +2464,7 @@ int ggml_metal_op_mul_mat(ggml_metal_op_t ctx, int idx) {
         ggml_metal_encoder_set_buffer  (enc, ggml_metal_get_buffer_id(op),         3);
 
         ggml_metal_encoder_dispatch_threadgroups(enc, ((ne01 + r0ptg - 1)/r0ptg), ((ne11 + r1ptg - 1)/r1ptg), ne12*ne13, 32, nsg, 1);
-    } else if (
-        !ggml_is_transposed(op->src[0]) &&
-        !ggml_is_transposed(op->src[1]) &&
-        // for now the matrix-matrix multiplication kernel only works on A14+/M1+ SoCs
-        // AMD GPU and older A-chips will reuse matrix-vector multiplication kernel
-        props_dev->has_simdgroup_mm && ne00 >= 64 && ne11 > ne11_mm_min) {
+    } else if (ggml_metal_op_mul_mat_use_mm(op, props_dev->has_simdgroup_mm)) {
         //GGML_LOG_INFO("matrix: ne00 = %6d, ne01 = %6d, ne02 = %6d, ne11 = %6d, ne12 = %6d\n", ne00, ne01, ne02, ne11, ne12);
 
         // some Metal matrix data types require aligned pointers
@@ -2622,13 +2613,7 @@ int ggml_metal_op_mul_mat_id(ggml_metal_op_t ctx, int idx) {
     const uint32_t r2 = 1;
     const uint32_t r3 = 1;
 
-    // find the break-even point where the matrix-matrix kernel becomes more efficient compared
-    // to the matrix-vector kernel
-    // ne20 = n_used_experts
-    // ne21 = n_rows (batch size)
-    const int ne21_mm_id_min = 32;
-
-    if (props_dev->has_simdgroup_mm && ne00 >= 64 && (ne21 >= ne21_mm_id_min)) {
+    if (ggml_metal_op_mul_mat_id_use_mm(op, props_dev->has_simdgroup_mm)) {
         // some Metal matrix data types require aligned pointers
         // ref: https://developer.apple.com/metal/Metal-Shading-Language-Specification.pdf (Table 2.5)
         //switch (op->src[0]->type) {