message: The wide-const must be lower priority than the Relu - and all other
  ops which might otherwise look for a constant.
diff: @@ -25,6 +25,7 @@ namespace poplarplugin {
  static const char* names[] = {
  "const_slice_update",
  "const_slice",
  + "wide_const",
  "relu",
  "sigmoid",
  "biasadd_broadcast",
  @@ -39,7 +40,6 @@ static const char* names[] = {
  "bernoulli",
  "avgpool_same",
  "avgpool_valid",
  - "wide_const",
  "depthwise_conv",
  };
  @@ -62,6 +62,10 @@ static const std::vector<HloMatcherPattern> patterns = {
  {{HloOpcode::kDynamicSlice, true, nullptr, {-1, 1}},
  {HloOpcode::kConstant, true, nullptr, {}}},
  + // Broadcast scalar constant (must precede Relu)
  + {{HloOpcode::kBroadcast, true, nullptr, {1}},
  + {HloOpcode::kConstant, true, IsScalarConstant, {}}},
  +
  // Relu
  {{HloOpcode::kMaximum, true, nullptr, {-1, 1}},
  {HloOpcode::kConstant, true, IsConstantZero, {}}},
  @@ -150,10 +154,6 @@ static const std::vector<HloMatcherPattern> patterns = {
  {HloOpcode::kConstant, true, nullptr, {}},
  {HloOpcode::kConstant, true, nullptr, {}}},
  - // Broadcast scalar constant
  - {{HloOpcode::kBroadcast, true, nullptr, {1}},
  - {HloOpcode::kConstant, true, IsScalarConstant, {}}},
  -
  // Depthwise convolution (forward pass)
  {{HloOpcode::kConvolution, true, nullptr, {-1, 1}},
  {HloOpcode::kReshape, true, nullptr, {2}},
  