diff --git a/mlir/lib/Dialect/Affine/Utils/LoopUtils.cpp b/mlir/lib/Dialect/Affine/Utils/LoopUtils.cpp
--- a/mlir/lib/Dialect/Affine/Utils/LoopUtils.cpp
+++ b/mlir/lib/Dialect/Affine/Utils/LoopUtils.cpp
@@ -2183,8 +2183,7 @@
     // fastMemRefType is a constant shaped memref.
     auto maySizeInBytes = getIntOrFloatMemRefSizeInBytes(fastMemRefType);
     // We don't account for things of unknown size.
-    if (!maySizeInBytes)
-      maySizeInBytes = 0;
+    *sizeInBytes == maySizeInBytes ? *maySizeInBytes : 0;
 
     LLVM_DEBUG(emitRemarkForBlock(*block)
                << "Creating fast buffer of type " << fastMemRefType
@@ -2554,13 +2553,13 @@
   if (llvm::DebugFlag && (forOp = dyn_cast<AffineForOp>(&*begin))) {
     LLVM_DEBUG(forOp.emitRemark()
                << llvm::divideCeil(totalCopyBuffersSizeInBytes, 1024)
-               << " KiB of copy buffers in fast memory space for this block\n");
+               << " KiB of copy buffers in fast memory space for this block");
   }
 
   if (totalCopyBuffersSizeInBytes > copyOptions.fastMemCapacityBytes) {
-    StringRef str = "Total size of all copy buffers' for this block "
-                    "exceeds fast memory capacity\n";
-    block->getParentOp()->emitWarning(str);
+    block->getParentOp()->emitWarning(
+        "total size of all copy buffers' for this block exceeds fast memory "
+        "capacity");
   }
 
   return success();