From 0db351113204a31905e7f0bb118ddd5f2178f484 Mon Sep 17 00:00:00 2001
From: Gaetan Lepage <gaetan@glepage.com>
Date: Thu, 23 Apr 2026 13:14:02 +0000
Subject: [PATCH] cudaPackages.cuda_crt: patch math_functions.h signatures

---
 .../cuda-modules/packages/cuda_crt.nix        | 31 ++++++++++++++++++-
 .../cuda-modules/packages/cuda_nvcc.nix       |  6 ++++
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/pkgs/development/cuda-modules/packages/cuda_crt.nix b/pkgs/development/cuda-modules/packages/cuda_crt.nix
index 3cf2246235bd..914967d7cc8d 100644
--- a/pkgs/development/cuda-modules/packages/cuda_crt.nix
+++ b/pkgs/development/cuda-modules/packages/cuda_crt.nix
@@ -1,10 +1,39 @@
-{ backendStdenv, buildRedist }:
+{
+  lib,
+  backendStdenv,
+  buildRedist,
+  glibc,
+}:
 buildRedist {
   redistName = "cuda";
   pname = "cuda_crt";
 
   outputs = [ "out" ];
 
+  # Fix compatibility with glibc 2.42:
+  # CUDA >= 13.0 fixed sinpi/cospi (using __NV_IEC_60559_FUNCS_EXCEPTION_SPECIFIER), but
+  # rsqrt/rsqrtf in math_functions.h still lack noexcept, conflicting with glibc 2.42's
+  # declarations.
+  postInstall = lib.optionalString (lib.versionAtLeast glibc.version "2.42") ''
+    nixLog "Patching math_functions.h rsqrt signatures to match glibc's ones"
+    substituteInPlace "''${!outputInclude:?}/include/crt/math_functions.h" \
+      --replace-fail \
+        "rsqrt(double x);" \
+        "rsqrt(double x) noexcept (true);" \
+      --replace-fail \
+        "rsqrtf(float x);" \
+        "rsqrtf(float x) noexcept (true);"
+
+    nixLog "Patching math_functions.hpp rsqrt signatures to match glibc's ones"
+    substituteInPlace "''${!outputInclude:?}/include/crt/math_functions.hpp" \
+      --replace-fail \
+        "__func__(double rsqrt(const double a))" \
+        "__func__(double rsqrt(const double a) throw())" \
+      --replace-fail \
+        "__func__(float rsqrtf(const float a))" \
+        "__func__(float rsqrtf(const float a) throw())"
+  '';
+
   brokenAssertions = [
     # TODO(@connorbaker): Build fails on x86 when using pkgsLLVM.
     #  .../include/crt/host_defines.h:67:2:
diff --git a/pkgs/development/cuda-modules/packages/cuda_nvcc.nix b/pkgs/development/cuda-modules/packages/cuda_nvcc.nix
index 404811ffa2f5..2bb34f2cf84f 100644
--- a/pkgs/development/cuda-modules/packages/cuda_nvcc.nix
+++ b/pkgs/development/cuda-modules/packages/cuda_nvcc.nix
@@ -168,6 +168,11 @@ buildRedist (finalAttrs: {
       # The cospi|sinpi|rsqrt function signatures in include/common/math_functions.h do not match
       # glibc 2.42's.
       # Indeed, there they are declared with noexcept(true) which is not the case in cuda_nvcc.
+      # - In CUDA < 13.0, sinpi/cospi/rsqrt all lack exception specifiers.
+      # - In CUDA >= 13.0, NVIDIA fixed sinpi/cospi (using __NV_IEC_60559_FUNCS_EXCEPTION_SPECIFIER)
+      #   but rsqrt/rsqrtf still lack noexcept, so we only patch those.
+      #   As the CRT headers (including math_functions.h) moved to the cuda_crt package, the glibc
+      #   2.42 compatibility patch is applied there instead.
       + lib.optionalString (cudaOlder "13.0" && lib.versionAtLeast glibc.version "2.42") ''
         nixLog "Patching math_functions.h signatures to match glibc's ones"
         substituteInPlace "''${!outputInclude:?}/include/crt/math_functions.h" \
@@ -213,6 +218,7 @@ buildRedist (finalAttrs: {
             "__func__(float cospif(const float a))" \
             "__func__(float cospif(const float a) throw())"
       ''
+
       # Fix clang CUDA compilation: host_defines.h redefines __noinline__ as
       # __attribute__((noinline)), which conflicts with libstdc++ >=12 using
       # __attribute__((__noinline__)) — the macro expands to