[llvm] [OFFLOAD][L0] Fix PatternSize assert in L0QueueTy::memoryFill (PR #210867)

[Wenju He via llvm-commits]

https://github.com/wenju-he created https://github.com/llvm/llvm-project/pull/210867

The message was the opposite of the assert condition.

In addition, when PatternSize == Size the caller wants to fill the region with exactly one copy of the pattern, which is a valid operation.

The issue was found by AI.

Also check `Size % PatternSize == 0` per L0 spec.

>From cf5e4040ed0d62c9df702fdb7416a9277ca684fe Mon Sep 17 00:00:00 2001
From: Wenju He <wenju.he at intel.com>
Date: Tue, 21 Jul 2026 05:05:13 +0200
Subject: [PATCH] [OFFLOAD][L0] Fix PatternSize assert in L0QueueTy::memoryFill

The message was the opposite of the assert condition.

In addition, when PatternSize == Size the caller wants to fill the
region with exactly one copy of the pattern, which is a valid operation.

The issue was found by AI.

Also check `Size % PatternSize == 0` per L0 spec.
---
 offload/plugins-nextgen/level_zero/src/L0Queue.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/offload/plugins-nextgen/level_zero/src/L0Queue.cpp b/offload/plugins-nextgen/level_zero/src/L0Queue.cpp
index f9c5bf11286c5..767c84ff80fe7 100644
--- a/offload/plugins-nextgen/level_zero/src/L0Queue.cpp
+++ b/offload/plugins-nextgen/level_zero/src/L0Queue.cpp
@@ -65,12 +65,12 @@ Error L0QueueTy::dispatchLaunchKernel(ze_kernel_handle_t Kernel,
 
 Error L0QueueTy::memoryFill(void *Ptr, const void *Pattern, size_t PatternSize,
                             size_t Size) {
-  assert(PatternSize < Size && "PatternSize < Size is unsupported");
+  assert(PatternSize <= Size && "PatternSize > Size is unsupported");
 
   if (Size == 0 || PatternSize == 0)
     return Plugin::success();
 
-  if (llvm::isPowerOf2_64(PatternSize) &&
+  if (llvm::isPowerOf2_64(PatternSize) && (Size % PatternSize == 0) &&
       PatternSize <= Device.getMaxMemFillPatternSize()) {
     // Native L0 memory fill is possible directly.
     return memoryFillImpl(Ptr, Pattern, PatternSize, Size);