From 5f7ff1085a591a499981c06474f24908ae6d5d85 Mon Sep 17 00:00:00 2001
From: Eman Resu <78693624+quatquatt@users.noreply.github.com>
Date: Sun, 3 May 2026 00:44:51 -0400
Subject: [PATCH 1/2] gcc: pass result of lib.systems.equals around rather than
 recomputing

---
 pkgs/development/compilers/gcc/all.nix        | 26 ++++------
 .../compilers/gcc/common/builder.nix          |  3 +-
 .../compilers/gcc/common/checksum.nix         | 11 ++---
 .../compilers/gcc/common/configure-flags.nix  | 19 +++----
 .../compilers/gcc/common/dependencies.nix     |  8 +--
 .../gcc/common/extra-target-flags.nix         |  9 ++--
 .../compilers/gcc/common/libgcc.nix           | 24 ++++-----
 .../compilers/gcc/common/pre-configure.nix    | 25 ++++------
 pkgs/development/compilers/gcc/default.nix    | 49 +++++++++++--------
 .../compilers/gcc/patches/default.nix         |  7 ++-
 10 files changed, 80 insertions(+), 101 deletions(-)

diff --git a/pkgs/development/compilers/gcc/all.nix b/pkgs/development/compilers/gcc/all.nix
index 26fa34c03c30..6445bee64264 100644
--- a/pkgs/development/compilers/gcc/all.nix
+++ b/pkgs/development/compilers/gcc/all.nix
@@ -13,6 +13,9 @@
 
 let
   versions = import ./versions.nix;
+  buildIsHost = lib.systems.equals stdenv.buildPlatform stdenv.hostPlatform;
+  buildIsTarget = lib.systems.equals stdenv.buildPlatform stdenv.targetPlatform;
+  hostIsTarget = lib.systems.equals stdenv.hostPlatform stdenv.targetPlatform;
   gccForMajorMinorVersion =
     majorMinorVersion:
     let
@@ -24,18 +27,13 @@ let
           callPackage ./default.nix {
             inherit noSysDirs;
             inherit majorMinorVersion;
+            _systemInfo = {
+              inherit buildIsHost hostIsTarget;
+            };
             reproducibleBuild = true;
             profiledCompiler = false;
-            libcCross =
-              if !lib.systems.equals stdenv.targetPlatform stdenv.buildPlatform then
-                targetPackages.libc or pkgs.libc
-              else
-                null;
-            threadsCross =
-              if !lib.systems.equals stdenv.targetPlatform stdenv.buildPlatform then
-                targetPackages.threads or pkgs.threads
-              else
-                { };
+            libcCross = if !buildIsTarget then targetPackages.libc or pkgs.libc else null;
+            threadsCross = if !buildIsTarget then targetPackages.threads or pkgs.threads else { };
             isl = if stdenv.hostPlatform.isDarwin then null else isl_0_20;
             # do not allow version skew when cross-building gcc
             #
@@ -56,13 +54,7 @@ let
             # Let's fix both problems by requiring the same compiler version for
             # cross-case.
             stdenv =
-              if
-                (
-                  (!lib.systems.equals stdenv.targetPlatform stdenv.buildPlatform)
-                  || (!lib.systems.equals stdenv.hostPlatform stdenv.targetPlatform)
-                )
-                && stdenv.cc.isGNU
-              then
+              if (!buildIsTarget || !hostIsTarget) && stdenv.cc.isGNU then
                 overrideCC stdenv buildPackages."gcc${majorVersion}"
               else
                 stdenv;
diff --git a/pkgs/development/compilers/gcc/common/builder.nix b/pkgs/development/compilers/gcc/common/builder.nix
index edd28a26ce95..e1e8a96ea8a3 100644
--- a/pkgs/development/compilers/gcc/common/builder.nix
+++ b/pkgs/development/compilers/gcc/common/builder.nix
@@ -3,11 +3,12 @@
   stdenv,
   enableMultilib,
   targetConfig,
+  hostIsTarget,
 }:
 
 let
   forceLibgccToBuildCrtStuff = import ./libgcc-buildstuff.nix { inherit lib stdenv; };
-  isCross = !lib.systems.equals stdenv.targetPlatform stdenv.hostPlatform;
+  isCross = !hostIsTarget;
 in
 
 # We don't support multilib and cross at the same time
diff --git a/pkgs/development/compilers/gcc/common/checksum.nix b/pkgs/development/compilers/gcc/common/checksum.nix
index a283d281c9ed..45c5e4340305 100644
--- a/pkgs/development/compilers/gcc/common/checksum.nix
+++ b/pkgs/development/compilers/gcc/common/checksum.nix
@@ -5,17 +5,12 @@
   langC,
   langCC,
   runtimeShell,
+  buildIsHost,
+  hostIsTarget,
 }:
 
 let
-  enableChecksum =
-    (
-      with stdenv;
-      lib.systems.equals buildPlatform hostPlatform && lib.systems.equals hostPlatform targetPlatform
-    )
-    && langC
-    && langCC
-    && !stdenv.hostPlatform.isDarwin;
+  enableChecksum = buildIsHost && hostIsTarget && langC && langCC && !stdenv.hostPlatform.isDarwin;
 in
 (
   pkg:
diff --git a/pkgs/development/compilers/gcc/common/configure-flags.nix b/pkgs/development/compilers/gcc/common/configure-flags.nix
index e2c735c0751f..66099c229743 100644
--- a/pkgs/development/compilers/gcc/common/configure-flags.nix
+++ b/pkgs/development/compilers/gcc/common/configure-flags.nix
@@ -32,7 +32,8 @@
   langObjCpp,
   langJit,
   langRust ? false,
-  disableBootstrap ? (!lib.systems.equals stdenv.targetPlatform stdenv.hostPlatform),
+  hostIsTarget,
+  disableBootstrap ? (!hostIsTarget),
 }:
 
 assert !enablePlugin -> disableGdbPlugin;
@@ -48,7 +49,6 @@ assert !enablePlugin -> disableGdbPlugin;
 
 let
   inherit (stdenv)
-    buildPlatform
     hostPlatform
     targetPlatform
     ;
@@ -56,9 +56,8 @@ let
   # See https://github.com/NixOS/nixpkgs/pull/209870#issuecomment-1500550903
   disableBootstrap' = disableBootstrap && !langFortran && !langGo;
 
-  crossMingw = (!lib.systems.equals targetPlatform hostPlatform) && targetPlatform.isMinGW;
-  crossDarwin =
-    (!lib.systems.equals targetPlatform hostPlatform) && targetPlatform.libc == "libSystem";
+  crossMingw = !hostIsTarget && targetPlatform.isMinGW;
+  crossDarwin = !hostIsTarget && targetPlatform.libc == "libSystem";
 
   crossConfigureFlags =
     # Ensure that -print-prog-name is able to find the correct programs.
@@ -247,20 +246,18 @@ let
     ++ lib.optional (isl != null) "--with-isl=${isl}"
 
     # Ada options, gcc can't build the runtime library for a cross compiler
-    ++ lib.optional langAda (
-      if lib.systems.equals hostPlatform targetPlatform then "--enable-libada" else "--disable-libada"
-    )
+    ++ lib.optional langAda (if hostIsTarget then "--enable-libada" else "--disable-libada")
 
     ++ import ../common/platform-flags.nix {
       inherit (stdenv) targetPlatform;
       inherit lib;
     }
-    ++ lib.optionals (!lib.systems.equals targetPlatform hostPlatform) crossConfigureFlags
+    ++ lib.optionals (!hostIsTarget) crossConfigureFlags
     ++ lib.optional disableBootstrap' "--disable-bootstrap"
 
     # Platform-specific flags
     ++ lib.optional (
-      lib.systems.equals targetPlatform hostPlatform && targetPlatform.isx86_32
+      hostIsTarget && targetPlatform.isx86_32
     ) "--with-arch=${stdenv.hostPlatform.parsed.cpu.name}"
     ++ lib.optional (targetPlatform.isNetBSD || targetPlatform.isCygwin) "--disable-libssp" # Provided by libc.
     ++ lib.optionals hostPlatform.isSunOS [
@@ -277,7 +274,7 @@ let
       lib.optional (targetPlatform.libc == "musl")
         # musl at least, disable: https://git.buildroot.net/buildroot/commit/?id=873d4019f7fb00f6a80592224236b3ba7d657865
         "--disable-libmpx"
-    ++ lib.optionals (lib.systems.equals targetPlatform hostPlatform && targetPlatform.libc == "musl") [
+    ++ lib.optionals (hostIsTarget && targetPlatform.libc == "musl") [
       "--disable-libsanitizer"
       "--disable-symvers"
       "libat_cv_have_ifunc=no"
diff --git a/pkgs/development/compilers/gcc/common/dependencies.nix b/pkgs/development/compilers/gcc/common/dependencies.nix
index c9e85c0d99fb..9d8feadde99e 100644
--- a/pkgs/development/compilers/gcc/common/dependencies.nix
+++ b/pkgs/development/compilers/gcc/common/dependencies.nix
@@ -27,11 +27,13 @@
   cargo,
   withoutTargetLibc ? null,
   threadsCross ? null,
+  buildIsHost,
+  hostIsTarget,
 }:
 
 let
   inherit (lib) optionals;
-  inherit (stdenv) buildPlatform hostPlatform targetPlatform;
+  inherit (stdenv) buildPlatform targetPlatform;
 in
 
 {
@@ -56,12 +58,12 @@ in
   # same for all gcc's
   depsBuildTarget =
     (
-      if lib.systems.equals hostPlatform buildPlatform then
+      if buildIsHost then
         [
           targetPackages.stdenv.cc.bintools # newly-built gcc will be used
         ]
       else
-        assert lib.systems.equals targetPlatform hostPlatform;
+        assert hostIsTarget;
         [
           # build != host == target
           stdenv.cc
diff --git a/pkgs/development/compilers/gcc/common/extra-target-flags.nix b/pkgs/development/compilers/gcc/common/extra-target-flags.nix
index 437a015dbf7b..fa078b87ff67 100644
--- a/pkgs/development/compilers/gcc/common/extra-target-flags.nix
+++ b/pkgs/development/compilers/gcc/common/extra-target-flags.nix
@@ -4,12 +4,9 @@
   withoutTargetLibc,
   libcCross,
   threadsCross,
+  hostIsTarget,
 }:
 
-let
-  inherit (stdenv) hostPlatform targetPlatform;
-in
-
 {
   # For non-cross builds these flags are currently assigned in builder.sh.
   # It would be good to consolidate the generation of makeFlags
@@ -18,7 +15,7 @@ in
     let
       mkFlags =
         dep:
-        lib.optionals ((!lib.systems.equals targetPlatform hostPlatform) && dep != null) (
+        lib.optionals (!hostIsTarget && dep != null) (
           [
             "-O2 -idirafter ${lib.getDev dep}${dep.incdir or "/include"}"
           ]
@@ -35,7 +32,7 @@ in
     let
       mkFlags =
         dep:
-        lib.optionals ((!lib.systems.equals targetPlatform hostPlatform) && dep != null) (
+        lib.optionals (!hostIsTarget && dep != null) (
           [
             "-Wl,-L${lib.getLib dep}${dep.libdir or "/lib"}"
           ]
diff --git a/pkgs/development/compilers/gcc/common/libgcc.nix b/pkgs/development/compilers/gcc/common/libgcc.nix
index c9f6a7793344..d937775d54f0 100644
--- a/pkgs/development/compilers/gcc/common/libgcc.nix
+++ b/pkgs/development/compilers/gcc/common/libgcc.nix
@@ -10,6 +10,7 @@
   hostPlatform,
   withoutTargetLibc,
   libcCross,
+  hostIsTarget,
 }:
 
 assert !stdenv.targetPlatform.hasSharedLibraries -> !enableShared;
@@ -24,27 +25,20 @@ lib.pipe drv
         pkg:
         pkg.overrideAttrs (
           previousAttrs:
-          lib.optionalAttrs
-            (
-              (!lib.systems.equals targetPlatform hostPlatform)
-              && (enableShared || targetPlatform.isMinGW)
-              && withoutTargetLibc
-            )
-            {
-              makeFlags = [
-                "all-gcc"
-                "all-target-libgcc"
-              ];
-              installTargets = "install-gcc install-target-libgcc";
-            }
+          lib.optionalAttrs (!hostIsTarget && (enableShared || targetPlatform.isMinGW) && withoutTargetLibc) {
+            makeFlags = [
+              "all-gcc"
+              "all-target-libgcc"
+            ];
+            installTargets = "install-gcc install-target-libgcc";
+          }
         )
       )
 
     ]
     ++ (
       let
-        targetPlatformSlash =
-          if lib.systems.equals hostPlatform targetPlatform then "" else "${targetPlatform.config}/";
+        targetPlatformSlash = if hostIsTarget then "" else "${targetPlatform.config}/";
 
         # If we are building a cross-compiler and the target libc provided
         # to us at build time has a libgcc, use that instead of building a
diff --git a/pkgs/development/compilers/gcc/common/pre-configure.nix b/pkgs/development/compilers/gcc/common/pre-configure.nix
index 806cbfc5b115..39c9d73fa232 100644
--- a/pkgs/development/compilers/gcc/common/pre-configure.nix
+++ b/pkgs/development/compilers/gcc/common/pre-configure.nix
@@ -14,6 +14,8 @@
   enableShared,
   enableMultilib,
   pkgsBuildTarget,
+  buildIsHost,
+  hostIsTarget,
 }:
 
 assert langAda -> gnat-bootstrap != null;
@@ -39,7 +41,7 @@ lib.optionalString (hostPlatform.isSunOS && hostPlatform.is64bit) ''
       langFortran
       && (
 
-        (!lib.systems.equals buildPlatform hostPlatform) && (lib.systems.equals hostPlatform targetPlatform)
+        !buildIsHost && hostIsTarget
       )
     )
     ''
@@ -57,12 +59,9 @@ lib.optionalString (hostPlatform.isSunOS && hostPlatform.is64bit) ''
 # HACK: if host and target config are the same, but the platforms are
 # actually different we need to convince the configure script that it
 # is in fact building a cross compiler although it doesn't believe it.
-+
-  lib.optionalString
-    (targetPlatform.config == hostPlatform.config && (!lib.systems.equals targetPlatform hostPlatform))
-    ''
-      substituteInPlace configure --replace is_cross_compiler=no is_cross_compiler=yes
-    ''
++ lib.optionalString (targetPlatform.config == hostPlatform.config && !hostIsTarget) ''
+  substituteInPlace configure --replace is_cross_compiler=no is_cross_compiler=yes
+''
 
 # Normally (for host != target case) --without-headers automatically
 # enables 'inhibit_libc=true' in gcc's gcc/configure.ac. But case of
@@ -71,11 +70,7 @@ lib.optionalString (hostPlatform.isSunOS && hostPlatform.is64bit) ''
 # We explicitly inhibit libc headers use in this case as well.
 +
   lib.optionalString
-    (
-      (!lib.systems.equals targetPlatform hostPlatform)
-      && withoutTargetLibc
-      && targetPlatform.config == hostPlatform.config
-    )
+    (!hostIsTarget && withoutTargetLibc && targetPlatform.config == hostPlatform.config)
     ''
       export inhibit_libc=true
     ''
@@ -93,6 +88,6 @@ lib.optionalString (hostPlatform.isSunOS && hostPlatform.is64bit) ''
   done
 ''
 
-+ lib.optionalString (
-  (!lib.systems.equals targetPlatform hostPlatform) && withoutTargetLibc && enableShared
-) (import ./libgcc-buildstuff.nix { inherit lib stdenv; })
++ lib.optionalString (!hostIsTarget && withoutTargetLibc && enableShared) (
+  import ./libgcc-buildstuff.nix { inherit lib stdenv; }
+)
diff --git a/pkgs/development/compilers/gcc/default.nix b/pkgs/development/compilers/gcc/default.nix
index f7a19a73673b..b7089add88f2 100644
--- a/pkgs/development/compilers/gcc/default.nix
+++ b/pkgs/development/compilers/gcc/default.nix
@@ -35,8 +35,14 @@
   zlib ? null,
   libucontext ? null,
   gnat-bootstrap ? null,
+  # Allows only computing system equality once across every file responsible for
+  # building gcc. Not part of the public API
+  _systemInfo ? {
+    buildIsHost = lib.systems.equals stdenv.buildPlatform stdenv.hostPlatform;
+    hostIsTarget = lib.systems.equals stdenv.hostPlatform stdenv.targetPlatform;
+  },
   enableMultilib ? false,
-  enablePlugin ? (lib.systems.equals stdenv.hostPlatform stdenv.buildPlatform), # Whether to support user-supplied plug-ins
+  enablePlugin ? _systemInfo.buildIsHost, # Whether to support user-supplied plug-ins
   name ? "gcc",
   libcCross ? null,
   threadsCross ? { }, # for MinGW
@@ -75,6 +81,8 @@ let
     versions
     ;
 
+  inherit (_systemInfo) buildIsHost hostIsTarget;
+
   gccVersions = import ./versions.nix;
   version = gccVersions.fromMajorMinor majorMinorVersion;
 
@@ -98,21 +106,16 @@ let
   disableBootstrap = !stdenv.hostPlatform.isDarwin && !profiledCompiler;
 
   inherit (stdenv) buildPlatform hostPlatform targetPlatform;
-  targetConfig =
-    if (!lib.systems.equals targetPlatform hostPlatform) then targetPlatform.config else null;
+  targetConfig = if (!hostIsTarget) then targetPlatform.config else null;
 
   patches = callFile ./patches { };
 
   # Cross-gcc settings (build == host != target)
-  crossMingw = (!lib.systems.equals targetPlatform hostPlatform) && targetPlatform.isMinGW;
+  crossMingw = (!hostIsTarget) && targetPlatform.isMinGW;
   stageNameAddon = optionalString withoutTargetLibc "-nolibc";
-  crossNameAddon = optionalString (
-    !lib.systems.equals targetPlatform hostPlatform
-  ) "${targetPlatform.config}${stageNameAddon}-";
+  crossNameAddon = optionalString (!hostIsTarget) "${targetPlatform.config}${stageNameAddon}-";
 
-  targetPrefix = lib.optionalString (
-    !lib.systems.equals stdenv.targetPlatform stdenv.hostPlatform
-  ) "${stdenv.targetPlatform.config}-";
+  targetPrefix = lib.optionalString (!hostIsTarget) "${stdenv.targetPlatform.config}-";
 
   callFile = callPackageWith {
     # lets
@@ -184,6 +187,8 @@ let
       which
       zlib
       ;
+
+    inherit buildIsHost hostIsTarget;
   };
 
 in
@@ -267,7 +272,7 @@ pipe
         substituteInPlace libgfortran/configure \
           --replace "-install_name \\\$rpath/\\\$soname" "-install_name ''${!outputLib}/lib/\\\$soname"
       ''
-      + (optionalString ((!lib.systems.equals targetPlatform hostPlatform) || stdenv.cc.libc != null)
+      + (optionalString ((!hostIsTarget) || stdenv.cc.libc != null)
         # On NixOS, use the right path to the dynamic linker instead of
         # `/lib/ld*.so'.
         (
@@ -337,11 +342,7 @@ pipe
         let
           target =
             optionalString profiledCompiler "profiled"
-            + optionalString (
-              (lib.systems.equals targetPlatform hostPlatform)
-              && (lib.systems.equals hostPlatform buildPlatform)
-              && !disableBootstrap
-            ) "bootstrap";
+            + optionalString (hostIsTarget && buildIsHost && !disableBootstrap) "bootstrap";
         in
         optional (target != "") target;
 
@@ -371,13 +372,11 @@ pipe
         # compiler (after the specs for the cross-gcc are created). Having
         # LIBRARY_PATH= makes gcc read the specs from ., and the build breaks.
 
-        CPATH = optionals (lib.systems.equals targetPlatform hostPlatform) (
+        CPATH = optionals hostIsTarget (
           makeSearchPathOutput "dev" "include" ([ ] ++ optional (zlib != null) zlib)
         );
 
-        LIBRARY_PATH = optionals (lib.systems.equals targetPlatform hostPlatform) (
-          makeLibraryPath (optional (zlib != null) zlib)
-        );
+        LIBRARY_PATH = optionals hostIsTarget (makeLibraryPath (optional (zlib != null) zlib));
 
         NIX_LDFLAGS = optionalString hostPlatform.isSunOS "-lm";
 
@@ -439,10 +438,18 @@ pipe
         langJit
         targetPlatform
         hostPlatform
+        hostIsTarget
         withoutTargetLibc
         enableShared
         libcCross
         ;
     })
-    (callPackage ./common/checksum.nix { inherit langC langCC; })
+    (callPackage ./common/checksum.nix {
+      inherit
+        langC
+        langCC
+        buildIsHost
+        hostIsTarget
+        ;
+    })
   ]
diff --git a/pkgs/development/compilers/gcc/patches/default.nix b/pkgs/development/compilers/gcc/patches/default.nix
index 2e412802742e..0c4117bae3db 100644
--- a/pkgs/development/compilers/gcc/patches/default.nix
+++ b/pkgs/development/compilers/gcc/patches/default.nix
@@ -23,6 +23,8 @@
   fetchurl,
   withoutTargetLibc,
   threadsCross,
+  buildIsHost,
+  hostIsTarget,
 }:
 
 let
@@ -36,10 +38,7 @@ let
   # aarch64-darwin, as it breaks building a foreign one:
   # https://github.com/iains/gcc-12-branch/issues/18
   canApplyIainsDarwinPatches =
-    stdenv.hostPlatform.isDarwin
-    && stdenv.hostPlatform.isAarch64
-    && (lib.systems.equals buildPlatform hostPlatform)
-    && (lib.systems.equals hostPlatform targetPlatform);
+    stdenv.hostPlatform.isDarwin && stdenv.hostPlatform.isAarch64 && buildIsHost && hostIsTarget;
 
   inherit (lib) optionals optional;
 in

From 5c17c2d6ce9797ed7501792677071638f759de49 Mon Sep 17 00:00:00 2001
From: Eman Resu <78693624+quatquatt@users.noreply.github.com>
Date: Mon, 11 May 2026 13:39:04 -0400
Subject: [PATCH 2/2] gcc: remove unused variables

---
 pkgs/development/compilers/gcc/all.nix     | 2 +-
 pkgs/development/compilers/gcc/default.nix | 7 -------
 2 files changed, 1 insertion(+), 8 deletions(-)

diff --git a/pkgs/development/compilers/gcc/all.nix b/pkgs/development/compilers/gcc/all.nix
index 6445bee64264..e47e31a1b5f2 100644
--- a/pkgs/development/compilers/gcc/all.nix
+++ b/pkgs/development/compilers/gcc/all.nix
@@ -9,7 +9,7 @@
   isl_0_20,
   noSysDirs,
   wrapCC,
-}@args:
+}:
 
 let
   versions = import ./versions.nix;
diff --git a/pkgs/development/compilers/gcc/default.nix b/pkgs/development/compilers/gcc/default.nix
index b7089add88f2..96e74e4708e4 100644
--- a/pkgs/development/compilers/gcc/default.nix
+++ b/pkgs/development/compilers/gcc/default.nix
@@ -65,9 +65,6 @@
 let
   inherit (lib)
     callPackageWith
-    filter
-    getBin
-    maintainers
     makeLibraryPath
     makeSearchPathOutput
     mapAttrs
@@ -76,8 +73,6 @@ let
     optionals
     optionalString
     pipe
-    platforms
-    versionAtLeast
     versions
     ;
 
@@ -87,8 +82,6 @@ let
   version = gccVersions.fromMajorMinor majorMinorVersion;
 
   majorVersion = versions.major version;
-  atLeast14 = versionAtLeast version "14";
-  is14 = majorVersion == "14";
   is13 = majorVersion == "13";
 
   # releases have a form: MAJOR.MINOR.MICRO, like 14.2.1