diff --git a/man8/ld.so.8 b/man8/ld.so.8
index 608cf7c55..da3340499 100644
--- a/man8/ld.so.8
+++ b/man8/ld.so.8
@@ -472,6 +472,16 @@ environment variable has been set.
 (ELF only)(glibc since 2.1.3)
 If set to a nonempty string, warn about unresolved symbols.
 .TP
+.B LD_PREFER_MAP_32BIT_EXEC
+(x86-64 only)(glibc since 2.23)
+According to Silvermont software optimization guide, for 64-bit
+applications, branch prediction performance can be negatively impacted
+when the target of a branch is more than 4GB away from the branch.
+If set, ld.so will try to map executable pages with MAP_32BIT first.
+NB: MAP_32BIT will map to lower 2GB, not lower 4GB, address.  Since
+MAP_32BIT reduces bits available for address space layout randomization
+(ASLR), LD_PREFER_MAP_32BIT_EXEC is always disabled for SUID programs.
+.TP
 .B LDD_ARGV0
 (libc5)
 .IR argv [0]