Merge pull request gevent#1820 from ikonst/patch-1

manylinux: disable -ffast-math
th0114nd · Oct 5, 2021 · 69f3613 · 69f3613
2 parents cf19786 + 5d7be4f
commit 69f3613
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diff --git a/docs/changes/1820.misc b/docs/changes/1820.misc
@@ -0,0 +1,3 @@
+Stop compiling manylinux wheels with ``-ffast-math.`` This was
+implicit in ``-Ofast``, but could alter the global state of the
+process. Analysis and fix thanks to Ilya Konstantinov.
diff --git a/scripts/releases/make-manylinux b/scripts/releases/make-manylinux
@@ -43,7 +43,9 @@ if [ "$DOCKER_IMAGE" == "quay.io/pypa/manylinux2014_aarch64" -a -n "$GITHUB_ACTI
     SLOW_ARM=1
 else
     echo "Compiling with -Ofast"
-    export CFLAGS="-Ofast $GEVENT_WARNFLAGS"
+    # Note: -Ofast includes -ffast-math which affects process-wide floating-point flags (e.g. can affect numpy).
+    #       We opt out of -ffast-math explicitly. Other libraries can still trigger it.
+    export CFLAGS="-Ofast -fno-fast-math $GEVENT_WARNFLAGS"
 fi
 # -lrt: Needed for clock_gettime libc support on this version.
 # -pthread: Needed for pthread_atfork (cffi).