Merge PR #540: [configure] Support for flambda flags.

1 files changed, 20 insertions, 0 deletions

diff --git a/INSTALL b/INSTALL
index 676a1f8ea..faac79f18 100644
--- a/INSTALL
+++ b/INSTALL
@@ -128,6 +128,26 @@ INSTALLATION PROCEDURE IN DETAILS (NORMAL USERS).
 	Use <command> to open an URL in a browser. %s must appear in <command>,
 	and will be replaced by the URL.
 
+-flambda-opts <flags>
+         This experimental option will pass specific user flags to the
+        OCaml optimizing compiler. In most cases, this option is used
+        to tweak the flambda backend; we recommend using
+
+        -flambda-opts `-O3 -unbox-closures`
+
+        but of course you are free to try with a different combination
+        of flags. You can read more at
+        https://caml.inria.fr/pub/docs/manual-ocaml/flambda.html
+
+        There is a known problem with certain OCaml versions and
+        `native_compute`, that will make compilation to require
+        a large amount of RAM (>= 10GiB) in some particular files.
+
+        We recommend disabling native compilation (`-native-compiler no`)
+        with flambda unless you use a modern (>= 4.06.0) OCaml.
+
+        c.f. https://caml.inria.fr/mantis/view.php?id=7630
+
 5- Still in the root directory, do
 
 	make