doc: improve -fsanitize=undefined description
gcc/ChangeLog:
* doc/invoke.texi: add link to UndefinedBehaviorSanitizer
documentation,
mention UBSAN_OPTIONS, similar to what is done for AddressSanitizer.
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 78cfc100ac2..f022885edf8 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -15200,7 +15200,8 @@ The option cannot be combined with
@option{-fsanitize=thread}.
@opindex fsanitize=undefined
Enable UndefinedBehaviorSanitizer, a fast undefined behavior detector.
Various computations are instrumented to detect undefined behavior
-at runtime. Current suboptions are:
+at runtime. See
@uref{https://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html} for more
details. The run-time behavior can be influenced using the
+@env{UBSAN_OPTIONS} environment variable. Current suboptions are:
@table @gcctabopt
