cherry-pick fix shape check in density_prior_box, test=release/1.6 (#21474)

Author: jerrywgz

paddle/fluid/operators/detection/density_prior_box_op.cc

@@ -29,11 +29,23 @@ class DensityPriorBoxOp : public framework::OperatorWithKernel {
     PADDLE_ENFORCE(image_dims.size() == 4, "The layout of image is NCHW.");
     PADDLE_ENFORCE(input_dims.size() == 4, "The layout of input is NCHW.");
 
-    PADDLE_ENFORCE_LT(input_dims[2], image_dims[2],
-                      "The height of input must smaller than image.");
-
-    PADDLE_ENFORCE_LT(input_dims[3], image_dims[3],
-                      "The width of input must smaller than image.");
+    if (ctx->IsRuntime()) {
+      PADDLE_ENFORCE_LT(
+          input_dims[2], image_dims[2],
+          platform::errors::InvalidArgument(
+              "The input tensor Input's height"
+              "of DensityPriorBoxOp should be smaller than input tensor Image's"
+              "hight. But received Input's height = %d, Image's height = %d",
+              input_dims[2], image_dims[2]));
+
+      PADDLE_ENFORCE_LT(
+          input_dims[3], image_dims[3],
+          platform::errors::InvalidArgument(
+              "The input tensor Input's width"
+              "of DensityPriorBoxOp should be smaller than input tensor Image's"
+              "width. But received Input's width = %d, Image's width = %d",
+              input_dims[3], image_dims[3]));
+    }
     auto variances = ctx->Attrs().Get<std::vector<float>>("variances");
 
     auto fixed_sizes = ctx->Attrs().Get<std::vector<float>>("fixed_sizes");
@@ -55,10 +67,13 @@ class DensityPriorBoxOp : public framework::OperatorWithKernel {
       dim_vec[3] = 4;
       ctx->SetOutputDim("Boxes", framework::make_ddim(dim_vec));
       ctx->SetOutputDim("Variances", framework::make_ddim(dim_vec));
-    } else {
+    } else if (ctx->IsRuntime()) {
       int64_t dim0 = input_dims[2] * input_dims[3] * num_priors;
       ctx->SetOutputDim("Boxes", {dim0, 4});
       ctx->SetOutputDim("Variances", {dim0, 4});
+    } else {
+      ctx->SetOutputDim("Boxes", {-1, 4});
+      ctx->SetOutputDim("Variances", {-1, 4});
     }
   }