diff --git a/pkgs/development/compilers/llvm/5/fix-gcc9.patch b/pkgs/development/compilers/llvm/5/fix-gcc9.patch
new file mode 100644
index 00000000000..eaf71f1468d
--- /dev/null
+++ b/pkgs/development/compilers/llvm/5/fix-gcc9.patch
@@ -0,0 +1,33 @@
+diff --git a/lib/Target/Mips/MipsFastISel.cpp b/lib/Target/Mips/MipsFastISel.cpp
+index f79cb0e6..c6279046 100644
+--- a/lib/Target/Mips/MipsFastISel.cpp
++++ b/lib/Target/Mips/MipsFastISel.cpp
+@@ -70,6 +70,7 @@
+ #include <cassert>
+ #include <cstdint>
+ #include <new>
++#include <array>
+ 
+ #define DEBUG_TYPE "mips-fastisel"
+ 
+@@ -1309,13 +1310,13 @@ bool MipsFastISel::fastLowerArguments() {
+     return false;
+   }
+ 
+-  const ArrayRef<MCPhysReg> GPR32ArgRegs = {Mips::A0, Mips::A1, Mips::A2,
+-                                            Mips::A3};
+-  const ArrayRef<MCPhysReg> FGR32ArgRegs = {Mips::F12, Mips::F14};
+-  const ArrayRef<MCPhysReg> AFGR64ArgRegs = {Mips::D6, Mips::D7};
+-  ArrayRef<MCPhysReg>::iterator NextGPR32 = GPR32ArgRegs.begin();
+-  ArrayRef<MCPhysReg>::iterator NextFGR32 = FGR32ArgRegs.begin();
+-  ArrayRef<MCPhysReg>::iterator NextAFGR64 = AFGR64ArgRegs.begin();
++   std::array<MCPhysReg, 4> GPR32ArgRegs = {{Mips::A0, Mips::A1, Mips::A2,
++                                            Mips::A3}};
++   std::array<MCPhysReg, 2> FGR32ArgRegs = {{Mips::F12, Mips::F14}};
++   std::array<MCPhysReg, 2> AFGR64ArgRegs = {{Mips::D6, Mips::D7}};
++   auto NextGPR32 = GPR32ArgRegs.begin();
++   auto NextFGR32 = FGR32ArgRegs.begin();
++   auto NextAFGR64 = AFGR64ArgRegs.begin();
+ 
+   struct AllocatedReg {
+     const TargetRegisterClass *RC;
diff --git a/pkgs/development/compilers/llvm/5/llvm.nix b/pkgs/development/compilers/llvm/5/llvm.nix
index 2fe7df7695b..a99b3fa96ae 100644
--- a/pkgs/development/compilers/llvm/5/llvm.nix
+++ b/pkgs/development/compilers/llvm/5/llvm.nix
@@ -49,6 +49,13 @@ stdenv.mkDerivation ({
       name = "llvm-gcc8-type-mismatch.patch";
       sha256 = "0ga2123aclq3x9w72d0rm0az12m8c1i4r1106vh701hf4cghgbch";
     })
+    ./fix-gcc9.patch
+    #(fetchpatch {
+    #  name = "llvm-fix-gcc9.patch";
+    #  url = "https://reviews.llvm.org/file/data/zs3ck5ryvc5n672fd2kw/PHID-FILE-byoqefzwmkd7qnlip4v2/file";
+    #  sha256 = "0injj1hqgrbcbihhwp2nbal88jfykad30r54f2cdcx7gws2fcy8i";
+    #  stripLen = 1;
+    #})
   ];
   postPatch = stdenv.lib.optionalString stdenv.isDarwin ''
     substituteInPlace cmake/modules/AddLLVM.cmake \