Simplify some code and add release assertions to help debug a crash in an application.

PiperOrigin-RevId: 361953871

3 files changed, 26 insertions, 9 deletions

diff --git a/ruy/kernel_common.h b/ruy/kernel_common.h
index 9509b8f..cff243b 100644
--- a/ruy/kernel_common.h
+++ b/ruy/kernel_common.h
@@ -177,6 +177,8 @@ void MakeKernelParams8bit(const PMat<std::int8_t>& lhs,
   params->prod_zp_depth = lhs.zero_point * rhs.zero_point * depth;
   params->flags |= RUY_ASM_FLAG_NEEDS_LEFT_SHIFT;
   if (mul_params.multiplier_fixedpoint_perchannel()) {
+    // Temporary release-assert to debug some crashes in an application.
+    RUY_CHECK(mul_params.multiplier_exponent_perchannel());
     params->flags |= RUY_ASM_FLAG_HAS_PERCHANNEL;
     params->multiplier_fixedpoint =
         mul_params.multiplier_fixedpoint_perchannel();
@@ -200,6 +202,11 @@ void MakeKernelParams8bit(const PMat<std::int8_t>& lhs,
   params->dst_type_id = DstTypeId<DstScalar>::kValue;
   params->dst_base_ptr =
       dst->data.get() + start_col * dst->layout.stride + start_row;
+
+  // Temporary release-asserts to debug some crashes in an application.
+  RUY_CHECK(params->multiplier_fixedpoint);
+  RUY_CHECK(params->multiplier_exponent);
+  RUY_CHECK(params->bias);
 }
 
 template <int LhsCols, int RhsCols>
diff --git a/ruy/mul_params.h b/ruy/mul_params.h
index 3535a75..42a5700 100644
--- a/ruy/mul_params.h
+++ b/ruy/mul_params.h
@@ -247,14 +247,22 @@ struct MulParamsStorage<std::int32_t, DstScalar> final {
   static_assert(sizeof(DstScalar) < sizeof(AccumScalar), "");
 
   const AccumScalar* bias = nullptr;
-  union {
-    const AccumScalar* multiplier_fixedpoint_perchannel = nullptr;
-    AccumScalar multiplier_fixedpoint;
-  };
-  union {
-    const int* multiplier_exponent_perchannel = nullptr;
-    int multiplier_exponent;
-  };
+  // union {  // This used to be a union, temporarily flattened to debug a crash
+  const AccumScalar* multiplier_fixedpoint_perchannel = nullptr;
+  // Let the default multiplier be effecively a multiplication by 1, so that
+  // the matmul behaves as a (saturating) plain integer matmul. Unfortunately
+  // 1 is not exactly representable in fixedpoint with 0 integer bits, but
+  // using the highest representable value is a sufficiently good
+  // approximation: since this specialization of MulParams is for the case
+  // where DstScalar is at least 2x narrower than MulScalar, the values
+  // for which there would be a difference will get saturated anyway.
+  AccumScalar multiplier_fixedpoint = 0;
+  //};
+  // union {  // This used to be a union, temporarily flattened to debug a crash
+  const int* multiplier_exponent_perchannel = nullptr;
+  // See the above comment about the default value of multiplier_fixedpoint.
+  int multiplier_exponent = 0;
+  // };
   DstScalar clamp_min = std::numeric_limits<DstScalar>::lowest();
   DstScalar clamp_max = std::numeric_limits<DstScalar>::max();
   ChannelDimension channel_dimension = ChannelDimension::kRow;
diff --git a/ruy/trmul_params.h b/ruy/trmul_params.h
index e68d909..486a6c6 100644
--- a/ruy/trmul_params.h
+++ b/ruy/trmul_params.h
@@ -53,7 +53,9 @@ constexpr int kMaxMulParamsSize =
                                 kMaxMulParamsSizeQuantizedIntegerCase));
 
 // OK to adjust as needed, but we want to avoid unnecessarily inflating that.
-static_assert(kMaxMulParamsSize <= 32, "");
+// Temporarily bumped from 32 to 48 as part of temporarily not using unions
+// in MulParams.
+static_assert(kMaxMulParamsSize <= 48, "");
 
 // Type-erased data needed for implementing TrMul.
 struct TrMulParams {