[Mlir-commits] [mlir] [mlir][ArmSME] Support 4-way widening outer products (PR #79288)

[Andrzej Warzyński]

================
@@ -291,6 +894,41 @@ func.func @outerproduct_widening_2way__bad_acc(%a0 : vector<[4]xf16>, %b0 : vect
 
 // -----
 
+// CHECK-LABEL: @outerproduct_widening_4way__bad_acc
+// CHECK-NOT: arm_sme.fmopa_4way
+// CHECK: arm_sme.outerproduct
+// CHECK: arm_sme.outerproduct
+// CHECK: arm_sme.outerproduct
+// CHECK: arm_sme.outerproduct
+// CHECK-NOT: arm_sme.fmopa_4way
+func.func @outerproduct_widening_4way__bad_acc(
+    %a0 : vector<[4]xi8>, %b0 : vector<[4]xi8>,
+    %a1 : vector<[4]xi8>, %b1 : vector<[4]xi8>,
+    %a2 : vector<[4]xi8>, %b2 : vector<[4]xi8>,
+    %a3 : vector<[4]xi8>, %b3 : vector<[4]xi8>) -> vector<[4]x[4]xi32> {
+  %a0_ext = arith.extsi %a0 : vector<[4]xi8> to vector<[4]xi32>
+  %b0_ext = arith.extsi %b0 : vector<[4]xi8> to vector<[4]xi32>
+
+  %a1_ext = arith.extsi %a1 : vector<[4]xi8> to vector<[4]xi32>
+  %b1_ext = arith.extsi %b1 : vector<[4]xi8> to vector<[4]xi32>
+
+  %a2_ext = arith.extsi %a2 : vector<[4]xi8> to vector<[4]xi32>
+  %b2_ext = arith.extsi %b2 : vector<[4]xi8> to vector<[4]xi32>
+
+  %a3_ext = arith.extsi %a3 : vector<[4]xi8> to vector<[4]xi32>
+  %b3_ext = arith.extsi %b3 : vector<[4]xi8> to vector<[4]xi32>
+
+  %0 = arm_sme.outerproduct %a0_ext, %b0_ext : vector<[4]xi32>, vector<[4]xi32>
+  %1 = arm_sme.outerproduct %a1_ext, %b1_ext acc(%0) : vector<[4]xi32>, vector<[4]xi32>
+  %2 = arm_sme.outerproduct %a2_ext, %b2_ext acc(%1) : vector<[4]xi32>, vector<[4]xi32>
+  // break chain
----------------
banach-space wrote:

```suggestion
  // Missing accumulate - breaks chain of use-def
```

https://github.com/llvm/llvm-project/pull/79288