From 56dd94b14d4ee35a305b97c59028309562d9e326 Mon Sep 17 00:00:00 2001
From: whispers <dawnofmidnight@duck.com>
Date: Sat, 20 Dec 2025 12:02:58 -0500
Subject: [PATCH] intel-graphics-compiler: fix build with gcc 15

LLVM 16, which this release of IGC is based on, fails to build with
GCC 15 due to a missing include of `<cstdint>` and an include of
`<ciso646>` instead of `<version>`. We patch LLVM directly in order to
fix these build failures.

Additionally, a warning under `-Wfree-nonheap-object` is emitted within
LLVM, and causes compile failures due to `-Werror`. In accordance with
IGC disabling warnings where they originate from within LLVM (see
`IGC/common/LLVMWarningsPush.hpp`), we patch in an ignore for this
warning.
---
 ...low-llvm-free-nonheap-object-warning.patch | 14 +++++++++++
 .../gcc15-llvm-header-fixes.patch             | 25 +++++++++++++++++++
 .../in/intel-graphics-compiler/package.nix    | 10 ++++++++
 3 files changed, 49 insertions(+)
 create mode 100644 pkgs/by-name/in/intel-graphics-compiler/gcc15-allow-llvm-free-nonheap-object-warning.patch
 create mode 100644 pkgs/by-name/in/intel-graphics-compiler/gcc15-llvm-header-fixes.patch

diff --git a/pkgs/by-name/in/intel-graphics-compiler/gcc15-allow-llvm-free-nonheap-object-warning.patch b/pkgs/by-name/in/intel-graphics-compiler/gcc15-allow-llvm-free-nonheap-object-warning.patch
new file mode 100644
index 000000000000..90cd81176d12
--- /dev/null
+++ b/pkgs/by-name/in/intel-graphics-compiler/gcc15-allow-llvm-free-nonheap-object-warning.patch
@@ -0,0 +1,14 @@
+diff --git a/igc/IGC/common/LLVMWarningsPush.hpp b/igc/IGC/common/LLVMWarningsPush.hpp
+index 12874dfcc2..38acd80943 100644
+--- a/igc/IGC/common/LLVMWarningsPush.hpp
++++ b/igc/IGC/common/LLVMWarningsPush.hpp
+@@ -43,6 +43,9 @@
+ #if __GNUC__ > 8
+ #pragma GCC diagnostic ignored "-Winit-list-lifetime"
+ #endif
++#if __GNUC__ > 14
++#pragma GCC diagnostic ignored "-Wfree-nonheap-object"
++#endif
+ #endif
+ 
+ #if defined(_WIN32) || defined(_WIN64)
diff --git a/pkgs/by-name/in/intel-graphics-compiler/gcc15-llvm-header-fixes.patch b/pkgs/by-name/in/intel-graphics-compiler/gcc15-llvm-header-fixes.patch
new file mode 100644
index 000000000000..b60b995a726c
--- /dev/null
+++ b/pkgs/by-name/in/intel-graphics-compiler/gcc15-llvm-header-fixes.patch
@@ -0,0 +1,25 @@
+diff --git a/llvm-project/llvm/include/llvm/ADT/SmallVector.h b/llvm-project/llvm/include/llvm/ADT/SmallVector.h
+index 98dce89168..a52947e16e 100644
+--- a/llvm-project/llvm/include/llvm/ADT/SmallVector.h
++++ b/llvm-project/llvm/include/llvm/ADT/SmallVector.h
+@@ -19,6 +19,7 @@
+ #include <algorithm>
+ #include <cassert>
+ #include <cstddef>
++#include <cstdint>
+ #include <cstdlib>
+ #include <cstring>
+ #include <functional>
+diff --git a/llvm-project/llvm/include/llvm/Support/Threading.h b/llvm-project/llvm/include/llvm/Support/Threading.h
+index ba6c531ab4..78aa5e7be5 100644
+--- a/llvm-project/llvm/include/llvm/Support/Threading.h
++++ b/llvm-project/llvm/include/llvm/Support/Threading.h
+@@ -18,7 +18,7 @@
+ #include "llvm/ADT/StringRef.h"
+ #include "llvm/Config/llvm-config.h" // for LLVM_ON_UNIX
+ #include "llvm/Support/Compiler.h"
+-#include <ciso646> // So we can check the C++ standard lib macros.
++#include <version> // So we can check the C++ standard lib macros.
+ #include <optional>
+ 
+ #if defined(_MSC_VER)
diff --git a/pkgs/by-name/in/intel-graphics-compiler/package.nix b/pkgs/by-name/in/intel-graphics-compiler/package.nix
index d3d217f9591d..2b70443cec1c 100644
--- a/pkgs/by-name/in/intel-graphics-compiler/package.nix
+++ b/pkgs/by-name/in/intel-graphics-compiler/package.nix
@@ -66,6 +66,16 @@ stdenv.mkDerivation rec {
     # https://github.com/intel/intel-graphics-compiler/commit/4f0123a7d67fb716b647f0ba5c1ab550abf2f97d
     # https://github.com/intel/intel-graphics-compiler/pull/364
     ./bump-cmake.patch
+
+    # Fix for GCC 15 by adding a previously-implicit `#include <cstdint>` and
+    # replacing `<ciso646>` with `<version>` in the the llvm directory. Based
+    # on https://github.com/intel/intel-graphics-compiler/pull/383.
+    ./gcc15-llvm-header-fixes.patch
+
+    # Fix for GCC 15 by disabling `-Werror` for `-Wfree-nonheap-object`
+    # warnings within LLVM. This is in accordance with IGC disabling warnings
+    # that originate from within LLVM (see `IGC/common/LLVMWarningsPush.hpp`).
+    ./gcc15-allow-llvm-free-nonheap-object-warning.patch
   ];
 
   sourceRoot = ".";