diff --git a/scripts/callgrind.bash b/scripts/callgrind.bash
index 9f13c7b..dd38a6b 100755
--- a/scripts/callgrind.bash
+++ b/scripts/callgrind.bash
@@ -4,10 +4,23 @@ set -euo pipefail
 IFS=$'\n\t'
 DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 
+: ${PROFILE:="perf"}
 
+function main {
+    local additional_flags=()
+    if [ "$PROFILE" = "dev" ] || [ "$PROFILE" = "debug" ]; then
+        PROFILE="debug"
+    else
+        additional_flags+=(--profile "$PROFILE")
+        # We have to disable avx512 because valgrind does not yet support it.
+        export RUSTFLAGS="-C target-feature=-avx512"
+    fi
 
-(cd "$DIR/../" && RUSTFLAGS="-C opt-level=0" cargo build --no-default-features)
-valgrind --tool=callgrind --callgrind-out-file="$DIR/../callgrind.out" "$DIR/../target/debug/parse" "${@}"
+    (cd "$DIR/../" && RUSTFLAGS="-C target-cpu=x86-64-v3" cargo build --no-default-features "${additional_flags[@]}")
+    valgrind --tool=callgrind --callgrind-out-file="$DIR/../callgrind.out" "$DIR/../target/${PROFILE}/parse" "${@}"
 
-echo "You probably want to run:"
-echo "callgrind_annotate --auto=yes '$DIR/../callgrind.out'"
+    echo "You probably want to run:"
+    echo "callgrind_annotate --auto=yes '$DIR/../callgrind.out'"
+}
+
+main "${@}"
diff --git a/src/lib.rs b/src/lib.rs
index c522cf6..de24125 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,4 +1,3 @@
-#![feature(round_char_boundary)]
 #![feature(exit_status_error)]
 #![feature(trait_alias)]
 // TODO: #![warn(missing_docs)]