diff --git a/llvm-project/0001-libc-Fix-build-when-__FE_DENORM-is-defined.patch b/llvm-project/0001-libc-Fix-build-when-__FE_DENORM-is-defined.patch
new file mode 100644
index 0000000..8d7ef53
--- /dev/null
+++ b/llvm-project/0001-libc-Fix-build-when-__FE_DENORM-is-defined.patch
@@ -0,0 +1,49 @@
+From 122da690b39a67cd6e6bce4b9ad3ac1470cc1ed5 Mon Sep 17 00:00:00 2001
+From: Alex Brachet <abrachet@google.com>
+Date: Wed, 8 Jun 2022 16:21:53 +0000
+Subject: [PATCH] [libc] Fix build when __FE_DENORM is defined
+
+[nd: drop hunk that doesn't apply to 14.0.1 due to missing
+  commit 805899e68a83 ("[libc] Change FEnv to use MXCSR as source of truth")]
+
+Differential revision: https://reviews.llvm.org/D127222
+---
+ libc/src/__support/FPUtil/x86_64/FEnvImpl.h | 10 +++++-----
+ 1 file changed, 5 insertions(+), 5 deletions(-)
+
+diff --git a/libc/src/__support/FPUtil/x86_64/FEnvImpl.h b/libc/src/__support/FPUtil/x86_64/FEnvImpl.h
+index 846996ec93af..6bac3e9e6a0f 100644
+--- a/libc/src/__support/FPUtil/x86_64/FEnvImpl.h
++++ b/libc/src/__support/FPUtil/x86_64/FEnvImpl.h
+@@ -73,7 +73,7 @@ static inline uint16_t get_status_value_for_except(int excepts) {
+   // bit flags in the control registers.
+   return (excepts & FE_INVALID ? ExceptionFlags::INVALID : 0) |
+ #ifdef __FE_DENORM
+-         (excepts & __FE_DENORM ? ExceptionFlags::Denormal : 0) |
++         (excepts & __FE_DENORM ? ExceptionFlags::DENORMAL : 0) |
+ #endif // __FE_DENORM
+          (excepts & FE_DIVBYZERO ? ExceptionFlags::DIV_BY_ZERO : 0) |
+          (excepts & FE_OVERFLOW ? ExceptionFlags::OVERFLOW : 0) |
+@@ -84,7 +84,7 @@ static inline uint16_t get_status_value_for_except(int excepts) {
+ static inline int exception_status_to_macro(uint16_t status) {
+   return (status & ExceptionFlags::INVALID ? FE_INVALID : 0) |
+ #ifdef __FE_DENORM
+-         (status & ExceptionFlags::Denormal ? __FE_DENORM : 0) |
++         (status & ExceptionFlags::DENORMAL ? __FE_DENORM : 0) |
+ #endif // __FE_DENORM
+          (status & ExceptionFlags::DIV_BY_ZERO ? FE_DIVBYZERO : 0) |
+          (status & ExceptionFlags::OVERFLOW ? FE_OVERFLOW : 0) |
+@@ -273,8 +273,8 @@ static inline int raise_except(int excepts) {
+   if (status_value & internal::ExceptionFlags::INEXACT)
+     raise_helper(internal::ExceptionFlags::INEXACT);
+ #ifdef __FE_DENORM
+-  if (statusValue & internal::ExceptionFlags::Denormal) {
+-    raiseHelper(internal::ExceptionFlags::Denormal);
++  if (status_value & internal::ExceptionFlags::DENORMAL) {
++    raise_helper(internal::ExceptionFlags::DENORMAL);
+   }
+ #endif // __FE_DENORM
+ 
+-- 
+2.37.0.144.g8ac04bfd2-goog
+
diff --git a/llvm-project/Dockerfile.epoch3 b/llvm-project/Dockerfile.epoch3
index 6752f25..229e1ea 100644
--- a/llvm-project/Dockerfile.epoch3
+++ b/llvm-project/Dockerfile.epoch3
@@ -80,6 +80,11 @@ RUN tar xf llvm-project-14.0.1.src.tar.xz && \
   mv llvm-project-14.0.1.src llvm-project
 RUN apk add cmake ninja python3
 COPY stage3.cmake llvm-project/.
+COPY 0001-libc-Fix-build-when-__FE_DENORM-is-defined.patch llvm-project/.
+RUN apk add patch
+RUN cd llvm-project && \
+  patch -p1 < 0001-libc-Fix-build-when-__FE_DENORM-is-defined.patch
+RUN apk del patch
 ARG LLVM_BUILD_DIR=llvm-project/llvm/build
 RUN cmake \
   -B ${LLVM_BUILD_DIR} \
@@ -87,6 +92,20 @@ RUN cmake \
   -D LLVM_DEFAULT_TARGET_TRIPLE=$(clang -print-target-triple) \
   -S llvm-project/llvm \
   -G Ninja
+
+RUN ninja -C ${LLVM_BUILD_DIR} llvmlibc
+COPY build_sparse_libc.sh ${LLVM_BUILD_DIR}/.
+RUN cd ${LLVM_BUILD_DIR} && \
+  ./build_sparse_libc.sh && \
+  mv libllvmlibc-sparse.a /sysroot/usr/lib/.
+
+RUN cmake \
+  -B ${LLVM_BUILD_DIR} \
+  -C llvm-project/stage3.cmake \
+  -D LLVM_DEFAULT_TARGET_TRIPLE=$(clang -print-target-triple) \
+  -S llvm-project/llvm \
+  -D CMAKE_EXE_LINKER_FLAGS="-static -lc++abi -ljemalloc -lllvmlibc-sparse -Wl,--allow-multiple-definition" \
+  -G Ninja
 RUN ninja -C ${LLVM_BUILD_DIR} install-clang install-lld
 RUN ninja -C ${LLVM_BUILD_DIR} install-clang-resource-headers
 RUN ninja -C ${LLVM_BUILD_DIR} \
diff --git a/llvm-project/build_sparse_libc.sh b/llvm-project/build_sparse_libc.sh
new file mode 100755
index 0000000..426be56
--- /dev/null
+++ b/llvm-project/build_sparse_libc.sh
@@ -0,0 +1,8 @@
+#!/usr/bin/env sh
+
+LLVM_LIBC=$(find . -name libllvmlibc.a)
+for i in strlen memcmp memset memcpy; do
+    llvm-ar x "${LLVM_LIBC}" $i.cpp.o
+done
+rm -f libllvmlibc-sparse.a
+llvm-ar qc libllvmlibc-sparse.a memcmp.cpp.o memcpy.cpp.o memset.cpp.o strlen.cpp.o
diff --git a/llvm-project/stage3.cmake b/llvm-project/stage3.cmake
index 4dedb42..c7335e3 100644
--- a/llvm-project/stage3.cmake
+++ b/llvm-project/stage3.cmake
@@ -46,8 +46,8 @@ set(LLVM_ENABLE_LIBCXX ON CACHE BOOL "")
 # Use lld from stage2.
 set(LLVM_ENABLE_LLD ON CACHE BOOL "")
 
-# Build clang, lld, and compiler-rt.
-set(LLVM_ENABLE_PROJECTS "clang;lld;compiler-rt" CACHE STRING "")
+# Build clang, lld, compiler-rt, and libc.
+set(LLVM_ENABLE_PROJECTS "clang;lld;compiler-rt;libc" CACHE STRING "")
 
 # FORCE_ON causes the build to fail if zlib is not found in the environment
 # during configuration, rather than much later during link.