diff --git a/acinclude.m4 b/acinclude.m4
index 626031c2895..48724f4f0b5 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -1739,6 +1739,42 @@ choke me
   fi
 ])
 
+dnl
+dnl PHP_BROKEN_GCC_STRLEN_OPT
+dnl
+dnl Early releases of GCC 8 shipped with a strlen() optimization bug, so they
+dnl didn't properly handle the `char val[1]` struct hack. See bug #76510.
+dnl
+AC_DEFUN([PHP_BROKEN_GCC_STRLEN_OPT], [
+  AC_CACHE_CHECK([for broken gcc optimize-strlen],ac_cv_have_broken_gcc_strlen_opt,[
+  AC_RUN_IFELSE([AC_LANG_SOURCE([[
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+struct s
+{
+  int i;
+  char c[1];
+};
+int main()
+{
+  struct s *s = malloc(sizeof(struct s) + 3);
+  s->i = 3;
+  strcpy(s->c, "foo");
+  return strlen(s->c+1) == 2;
+}
+]])],[
+  ac_cv_have_broken_gcc_strlen_opt=yes
+],[
+  ac_cv_have_broken_gcc_strlen_opt=no
+],[
+  ac_cv_have_broken_gcc_strlen_opt=no
+])])
+  if test "$ac_cv_have_broken_gcc_strlen_opt" = "yes"; then
+    CFLAGS="$CFLAGS -fno-optimize-strlen"
+  fi
+])
+
 dnl
 dnl PHP_FOPENCOOKIE
 dnl
diff --git a/configure.ac b/configure.ac
index aa5456e8c56..b7e7a78e03a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -500,6 +500,9 @@ immintrin.h
 PHP_FOPENCOOKIE
 PHP_BROKEN_GETCWD
 PHP_BROKEN_GLIBC_FOPEN_APPEND
+if test "$GCC" = "yes"; then
+  PHP_BROKEN_GCC_STRLEN_OPT
+fi
 
 dnl Checks for typedefs, structures, and compiler characteristics.
 dnl -------------------------------------------------------------------------