diff --git a/setup.py b/setup.py
index ce5309ee..9cb59461 100755
--- a/setup.py
+++ b/setup.py
@@ -278,7 +278,7 @@ def init_env(
         df += ' -Og'
         float_conversion = '-Wfloat-conversion'
     fortify_source = '' if sanitize and is_macos else '-D_FORTIFY_SOURCE=2'
-    optimize = df if debug or sanitize else '-O3'
+    optimize = ''
     sanitize_args = get_sanitize_args(cc, ccver) if sanitize else set()
     cppflags_ = os.environ.get(
         'OVERRIDE_CPPFLAGS', '-D{}DEBUG'.format('' if debug else 'N'),
@@ -289,7 +289,7 @@ def init_env(
     cflags_ = os.environ.get(
         'OVERRIDE_CFLAGS', (
             '-Wextra {} -Wno-missing-field-initializers -Wall -Wstrict-prototypes {}'
-            ' -pedantic-errors -Werror {} {} -fwrapv {} {} -pipe {} -fvisibility=hidden {}'
+            ' -pedantic-errors {} {} -fwrapv {} {} {} -fvisibility=hidden {}'
         ).format(
             float_conversion,
             '' if is_openbsd else '-std=c11',
@@ -306,7 +306,7 @@ def init_env(
     )
     ldflags_ = os.environ.get(
         'OVERRIDE_LDFLAGS',
-        '-Wall ' + ' '.join(sanitize_args) + ('' if debug else ' -O3')
+        '-Wall ' + ' '.join(sanitize_args)
     )
     ldflags = shlex.split(ldflags_)
     ldflags.append('-shared')
@@ -764,7 +764,7 @@ def safe_makedirs(path: str) -> None:
 
 
 def build_launcher(args: Options, launcher_dir: str = '.', bundle_type: str = 'source') -> None:
-    cflags = '-Wall -Werror -fpie'.split()
+    cflags = '-Wall -fpie'.split()
     cppflags = []
     libs: List[str] = []
     if args.profile or args.sanitize:
@@ -776,8 +776,6 @@ def build_launcher(args: Options, launcher_dir: str = '.', bundle_type: str = 's
             cflags.append('-g')
         if args.profile:
             libs.append('-lprofiler')
-    else:
-        cflags.append('-O3')
     if bundle_type.endswith('-freeze'):
         cppflags.append('-DFOR_BUNDLE')
         cppflags.append('-DPYVER="{}"'.format(sysconfig.get_python_version()))