gcc: Backport fix of GCC Issue 80431 from version 12

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80431

This bug annoys me because I hit it when working on Nix. It causes
miscompilations in such a way that I am hard-pressed to think how a
program could inadvertainly rely on the bug (such that it would be
broken by the fix).

The bug is longstanding, and the (quite small) applies without
modification to many older GCCs. I have confirmed by running the test in
that commit that does indeed fix the bug with the backports too.

pkgs/development/compilers/gcc/10/default.nix

@@ -51,8 +51,14 @@ let majorVersion = "10";
 
     inherit (stdenv) buildPlatform hostPlatform targetPlatform;
 
-    patches = [ ]
-      ++ optional (targetPlatform != hostPlatform) ../libstdc++-target.patch
+    patches = [
+      # Fix https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80431
+      (fetchurl {
+        name = "fix-bug-80431.patch";
+        url = "https://gcc.gnu.org/git/?p=gcc.git;a=patch;h=de31f5445b12fd9ab9969dc536d821fe6f0edad0";
+        sha256 = "0sd52c898msqg7m316zp0ryyj7l326cjcn2y19dcxqp15r74qj0g";
+      })
+    ] ++ optional (targetPlatform != hostPlatform) ../libstdc++-target.patch
       ++ optional noSysDirs ../no-sys-dirs.patch
       ++ optional (noSysDirs && hostPlatform.isRiscV) ../no-sys-dirs-riscv.patch
       /* ++ optional (hostPlatform != buildPlatform) (fetchpatch { # XXX: Refine when this should be applied

pkgs/development/compilers/gcc/11/default.nix

@@ -51,8 +51,14 @@ let majorVersion = "11";
 
     inherit (stdenv) buildPlatform hostPlatform targetPlatform;
 
-    patches =
-         optional (targetPlatform != hostPlatform) ../libstdc++-target.patch
+    patches = [
+      # Fix https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80431
+      (fetchurl {
+        name = "fix-bug-80431.patch";
+        url = "https://gcc.gnu.org/git/?p=gcc.git;a=patch;h=de31f5445b12fd9ab9969dc536d821fe6f0edad0";
+        sha256 = "0sd52c898msqg7m316zp0ryyj7l326cjcn2y19dcxqp15r74qj0g";
+      })
+    ] ++ optional (targetPlatform != hostPlatform) ../libstdc++-target.patch
       ++ optional noSysDirs ../no-sys-dirs.patch
       ++ optional (noSysDirs && hostPlatform.isRiscV) ../no-sys-dirs-riscv.patch
       /* ++ optional (hostPlatform != buildPlatform) (fetchpatch { # XXX: Refine when this should be applied

pkgs/development/compilers/gcc/6/default.nix

@@ -64,6 +64,13 @@ let majorVersion = "6";
 
     patches = optionals (!stdenv.targetPlatform.isRedox) [
       ../use-source-date-epoch.patch ./0001-Fix-build-for-glibc-2.31.patch
+
+      # Fix https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80431
+      (fetchurl {
+        name = "fix-bug-80431.patch";
+        url = "https://gcc.gnu.org/git/?p=gcc.git;a=patch;h=de31f5445b12fd9ab9969dc536d821fe6f0edad0";
+        sha256 = "0sd52c898msqg7m316zp0ryyj7l326cjcn2y19dcxqp15r74qj0g";
+      })
     ] ++ optional (targetPlatform != hostPlatform) ../libstdc++-target.patch
       ++ optional noSysDirs ../no-sys-dirs.patch
       ++ optional langAda ../gnat-cflags.patch

pkgs/development/compilers/gcc/7/default.nix

@@ -56,6 +56,13 @@ let majorVersion = "7";
         ./gcc8-asan-glibc-2.34.patch
 
         ./0001-Fix-build-for-glibc-2.31.patch
+
+        # Fix https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80431
+        (fetchurl {
+          name = "fix-bug-80431.patch";
+          url = "https://gcc.gnu.org/git/?p=gcc.git;a=patch;h=de31f5445b12fd9ab9969dc536d821fe6f0edad0";
+          sha256 = "0sd52c898msqg7m316zp0ryyj7l326cjcn2y19dcxqp15r74qj0g";
+        })
       ]
       ++ optional (targetPlatform != hostPlatform) ../libstdc++-target.patch
       ++ optionals targetPlatform.isNetBSD [

pkgs/development/compilers/gcc/8/default.nix

@@ -46,8 +46,14 @@ let majorVersion = "8";
 
     inherit (stdenv) buildPlatform hostPlatform targetPlatform;
 
-    patches =
-         optional (targetPlatform != hostPlatform) ../libstdc++-target.patch
+    patches = [
+      # Fix https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80431
+      (fetchurl {
+        name = "fix-bug-80431.patch";
+        url = "https://gcc.gnu.org/git/?p=gcc.git;a=patch;h=de31f5445b12fd9ab9969dc536d821fe6f0edad0";
+        sha256 = "0sd52c898msqg7m316zp0ryyj7l326cjcn2y19dcxqp15r74qj0g";
+      })
+    ] ++ optional (targetPlatform != hostPlatform) ../libstdc++-target.patch
       ++ optional targetPlatform.isNetBSD ../libstdc++-netbsd-ctypes.patch
       ++ optional noSysDirs ../no-sys-dirs.patch
       /* ++ optional (hostPlatform != buildPlatform) (fetchpatch { # XXX: Refine when this should be applied

pkgs/development/compilers/gcc/9/default.nix

@@ -55,9 +55,14 @@ let majorVersion = "9";
 
     inherit (stdenv) buildPlatform hostPlatform targetPlatform;
 
-    patches =
-      [ ]
-      ++ optional (targetPlatform != hostPlatform) ../libstdc++-target.patch
+    patches = [
+      # Fix https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80431
+      (fetchurl {
+        name = "fix-bug-80431.patch";
+        url = "https://gcc.gnu.org/git/?p=gcc.git;a=patch;h=de31f5445b12fd9ab9969dc536d821fe6f0edad0";
+        sha256 = "0sd52c898msqg7m316zp0ryyj7l326cjcn2y19dcxqp15r74qj0g";
+      })
+    ] ++ optional (targetPlatform != hostPlatform) ../libstdc++-target.patch
       ++ optional targetPlatform.isNetBSD ../libstdc++-netbsd-ctypes.patch
       ++ optional noSysDirs ../no-sys-dirs.patch
       ++ optional (noSysDirs && hostPlatform.isRiscV) ../no-sys-dirs-riscv-gcc9.patch