From adacaa3e170adf77b6c363e9ba80f63bfcc5bf5d Mon Sep 17 00:00:00 2001
From: nimlgen <138685161+nimlgen@users.noreply.github.com>
Date: Fri, 14 Aug 2026 16:23:59 +0300
Subject: [PATCH] hcq2 fix hangs (#17529)

---
 tinygrad/renderer/cstyle.py | 1 +
 tinygrad/renderer/llvmir.py | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/tinygrad/renderer/cstyle.py b/tinygrad/renderer/cstyle.py
index e25ab0c605..3b555ac177 100644
--- a/tinygrad/renderer/cstyle.py
+++ b/tinygrad/renderer/cstyle.py
@@ -264,6 +264,7 @@ class ClangRenderer(CStyleLanguage):
   nan = '__builtin_nanf("")'
 
   # language options
+  barrier = "__atomic_thread_fence(__ATOMIC_SEQ_CST);"
   buffer_suffix = " restrict"
   type_map = {dtypes.bool:"_Bool", dtypes.half:"__fp16"}
   code_for_op = {**({k:v for k,v in CStyleLanguage.code_for_op.items() if k not in [Ops.EXP2, Ops.SIN, Ops.LOG2, Ops.TRUNC, Ops.RECIPROCAL]}),
diff --git a/tinygrad/renderer/llvmir.py b/tinygrad/renderer/llvmir.py
index 05f6e72033..838e1c95f0 100644
--- a/tinygrad/renderer/llvmir.py
+++ b/tinygrad/renderer/llvmir.py
@@ -142,7 +142,7 @@ base_rewrite = PatternMatcher([
   (UPat(Ops.IF, name="x"), lambda ctx,x: f"  br i1 {ctx[x.src[0]]}, label %ifbody_{ctx[x][1:]}, label %ifskip_{ctx[x][1:]}\nifbody_{ctx[x][1:]}:"),
   (UPat(Ops.ENDIF, name="x"), lambda ctx,x: f"  br label %ifskip_{ctx[x.src[0]][1:]}\nifskip_{ctx[x.src[0]][1:]}:"),
 
-  (UPat(Ops.BARRIER), lambda ctx: "")
+  (UPat(Ops.BARRIER), lambda ctx: "  fence seq_cst")
 ])
 
 class LLVMRenderer(Renderer):