diff --git a/.appveyor.yml b/.appveyor.yml
index 760e3018c0..ee089ca75e 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -1,9 +1,4 @@
 environment:
-  # We don't want to do identical comdat folding as it messes up the ability to
-  # generate lossless backtraces in some cases. This is enabled by rustc by
-  # default so pass a flag to disable it to ensure our tests work ok.
-  RUSTFLAGS: -Clink-args=/OPT:NOICF
-
   matrix:
     - TARGET: x86_64-pc-windows-gnu
       MSYSTEM: MINGW64
@@ -12,11 +7,6 @@ environment:
       MSYSTEM: MINGW32
       CPU: i686
 
-matrix:
-  allow_failures:
-    - TARGET: x86_64-pc-windows-gnu
-    - TARGET: i686-pc-windows-gnu
-
 install:
   - git submodule update --init --recursive
   - set PATH=c:\msys64\%MSYSTEM%\bin;c:\msys64\usr\bin;%PATH%
@@ -28,7 +18,3 @@ install:
   - cargo -vV
 build: false
 test_script: sh ci\run.sh
-
-branches:
-  only:
-    - master
diff --git a/ci/run.sh b/ci/run.sh
index 06ae69cfc6..ab27038165 100755
--- a/ci/run.sh
+++ b/ci/run.sh
@@ -28,7 +28,10 @@ fi
 # Use cargo on native CI platforms:
 case "${TARGET}" in
     "x86_64-unknown-linux-gnu") export CARGO_CMD=cargo ;;
-    *"windows"*) export CARGO_CMD=cargo ;;
+    *"windows"*)
+        export CARGO_CMD=cargo
+        export NOBGT=1
+        ;;
     *"apple"*) export CARGO_CMD=cargo ;;
 esac
 
@@ -53,10 +56,11 @@ then
     esac
 fi
 
-if [ "${TARGET}" = "x86_64-unknown-linux-gnu" ] || [ "${TARGET}" = "x86_64-apple-darwin" ]
-then
-    ${CARGO_CMD} build -vv --target "${TARGET}" 2>&1 | tee build_no_std.txt
+${CARGO_CMD} test -vv --target "${TARGET}" 2>&1 | tee build_no_std.txt
 
+if [ "${TARGET}" = "x86_64-unknown-linux-gnu" ] \
+       || [ "${TARGET}" = "x86_64-apple-darwin" ]
+then
     # Check that the no-std builds are not linked against a libc with default
     # features or the `use_std` feature enabled:
     ! grep -q "default" build_no_std.txt
@@ -71,17 +75,36 @@ then
     done
 fi
 
-${CARGO_CMD} test -vv --target "${TARGET}"
-${CARGO_CMD} test -vv --target "${TARGET}" --features profiling
-${CARGO_CMD} test -vv --target "${TARGET}" --features debug
-${CARGO_CMD} test -vv --target "${TARGET}" --features stats
-${CARGO_CMD} test -vv --target "${TARGET}" --features 'debug profiling'
 ${CARGO_CMD} test -vv --target "${TARGET}" \
-             --features unprefixed_malloc_on_supported_platforms
-${CARGO_CMD} test -vv --target "${TARGET}" --no-default-features
+             --no-default-features \
+             --features debug,stats,background_threads_runtime_support,\
+             unprefixed_malloc_on_supported_platforms
 ${CARGO_CMD} test -vv --target "${TARGET}" --no-default-features \
              --features background_threads_runtime_support
 
+# jemalloc's tests fail on some targets when the profiling feature is enabled:
+# https://github.com/jemalloc/jemalloc/issues/1320
+# https://github.com/alexcrichton/jemallocator/issues/85
+case "${TARGET}" in
+    *"windows"*)
+        unset JEMALLOC_SYS_RUN_JEMALLOC_TESTS
+
+        ${CARGO_CMD} test -vv \
+                     --target "${TARGET}" --features profiling
+
+        if [ "${NO_JEMALLOC_TESTS}" = "1" ]
+        then
+            :
+        else
+            export JEMALLOC_SYS_RUN_JEMALLOC_TESTS=1
+        fi
+
+        ;;
+    *)
+        ${CARGO_CMD} test -vv --target "${TARGET}" --features profiling
+        ;;
+esac
+
 if [ "${NOBGT}" = "1" ]
 then
     echo "enabling background threads by default at run-time is not tested"
diff --git a/jemalloc-sys/build.rs b/jemalloc-sys/build.rs
index 4b6041fea0..609bf6a8b7 100644
--- a/jemalloc-sys/build.rs
+++ b/jemalloc-sys/build.rs
@@ -42,7 +42,7 @@ const NO_BG_THREAD_TARGETS: &[&str] = &["musl"];
 // https://github.com/rust-lang/rust/commit/536011d929ecbd1170baf34e09580e567c971f95
 // https://github.com/rust-lang/rust/commit/9f3de647326fbe50e0e283b9018ab7c41abccde3
 // https://github.com/rust-lang/rust/commit/ed015456a114ae907a36af80c06f81ea93182a24
-const NO_UNPREFIXED_MALLOC: &[&str] = &["android", "dragonfly", "musl", "darwin"];
+const NO_UNPREFIXED_MALLOC: &[&str] = &["android", "dragonfly", "musl", "darwin", "windows"];
 
 macro_rules! info {
     ($($args:tt)*) => { println!($($args)*) }
diff --git a/jemalloc-sys/jemalloc b/jemalloc-sys/jemalloc
index 61efbda709..d66f976628 160000
--- a/jemalloc-sys/jemalloc
+++ b/jemalloc-sys/jemalloc
@@ -1 +1 @@
-Subproject commit 61efbda7098de6fe64c362d309824864308c36d4
+Subproject commit d66f97662879a1a0c61ee12ba4b760fa6f458eef