Improve performance by avoiding strtoumax

This made (string-to-number "10") 20% faster on my old desktop,
an AMD Phenom II X4 910e running Fedora 25 x86-64.
* admin/merge-gnulib (GNULIB_MODULES): Remove strtoumax.
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.
* lib/strtoul.c, lib/strtoull.c, lib/strtoumax.c, m4/strtoull.m4:
* m4/strtoumax.m4: Remove.
* src/editfns.c (str2num): New function.
(styled_format): Use it instead of strtoumax.  Use ptrdiff_t
instead of uintmax_t.  Check for integer overflow.
* src/lread.c (LEAD_INT, DOT_CHAR, TRAIL_INT, E_EXP):
Move to private scope and make them enums.
(string_to_number): Compute integer value directly during
first pass instead of revisiting it with strtoumax later.

10 files changed, 58 insertions, 202 deletions

diff --git a/admin/merge-gnulib b/admin/merge-gnulib
index 45e4a788a35..e5fb0f59fb3 100755
--- a/admin/merge-gnulib
+++ b/admin/merge-gnulib
@@ -38,7 +38,7 @@ GNULIB_MODULES='
   manywarnings memrchr mkostemp mktime
   pipe2 pselect pthread_sigmask putenv qcopy-acl readlink readlinkat
   sig2str socklen stat-time std-gnu11 stdalign stddef stdio
-  stpcpy strftime strtoimax strtoumax symlink sys_stat
+  stpcpy strftime strtoimax symlink sys_stat
   sys_time time time_r time_rz timegm timer-time timespec-add timespec-sub
   update-copyright utimens
   vla warnings
diff --git a/lib/gnulib.mk.in b/lib/gnulib.mk.in
index d23c2a57ec3..73d304307d4 100644
--- a/lib/gnulib.mk.in
+++ b/lib/gnulib.mk.in
@@ -21,7 +21,7 @@
 # the same distribution terms as the rest of that program.
 #
 # Generated by gnulib-tool.
-# Reproduce by: gnulib-tool --import --lib=libgnu --source-base=lib --m4-base=m4 --doc-base=doc --tests-base=tests --aux-dir=build-aux --avoid=close --avoid=dup --avoid=fchdir --avoid=fstat --avoid=malloc-posix --avoid=msvc-inval --avoid=msvc-nothrow --avoid=open --avoid=openat-die --avoid=opendir --avoid=raise --avoid=save-cwd --avoid=select --avoid=setenv --avoid=sigprocmask --avoid=stat --avoid=stdarg --avoid=stdbool --avoid=threadlib --avoid=tzset --avoid=unsetenv --avoid=utime --avoid=utime-h --gnu-make --makefile-name=gnulib.mk.in --conditional-dependencies --no-libtool --macro-prefix=gl --no-vc-files alloca-opt binary-io byteswap c-ctype c-strcase careadlinkat close-stream count-leading-zeros count-one-bits count-trailing-zeros crypto/md5 crypto/sha1 crypto/sha256 crypto/sha512 dtoastr dtotimespec dup2 environ execinfo faccessat fcntl fcntl-h fdatasync fdopendir filemode filevercmp flexmember fstatat fsync getloadavg getopt-gnu gettime gettimeofday gitlog-to-changelog ignore-value intprops largefile lstat manywarnings memrchr mkostemp mktime pipe2 pselect pthread_sigmask putenv qcopy-acl readlink readlinkat sig2str socklen stat-time std-gnu11 stdalign stddef stdio stpcpy strftime strtoimax strtoumax symlink sys_stat sys_time time time_r time_rz timegm timer-time timespec-add timespec-sub update-copyright utimens vla warnings
+# Reproduce by: gnulib-tool --import --lib=libgnu --source-base=lib --m4-base=m4 --doc-base=doc --tests-base=tests --aux-dir=build-aux --avoid=close --avoid=dup --avoid=fchdir --avoid=fstat --avoid=malloc-posix --avoid=msvc-inval --avoid=msvc-nothrow --avoid=open --avoid=openat-die --avoid=opendir --avoid=raise --avoid=save-cwd --avoid=select --avoid=setenv --avoid=sigprocmask --avoid=stat --avoid=stdarg --avoid=stdbool --avoid=threadlib --avoid=tzset --avoid=unsetenv --avoid=utime --avoid=utime-h --gnu-make --makefile-name=gnulib.mk.in --conditional-dependencies --no-libtool --macro-prefix=gl --no-vc-files alloca-opt binary-io byteswap c-ctype c-strcase careadlinkat close-stream count-leading-zeros count-one-bits count-trailing-zeros crypto/md5 crypto/sha1 crypto/sha256 crypto/sha512 dtoastr dtotimespec dup2 environ execinfo faccessat fcntl fcntl-h fdatasync fdopendir filemode filevercmp flexmember fstatat fsync getloadavg getopt-gnu gettime gettimeofday gitlog-to-changelog ignore-value intprops largefile lstat manywarnings memrchr mkostemp mktime pipe2 pselect pthread_sigmask putenv qcopy-acl readlink readlinkat sig2str socklen stat-time std-gnu11 stdalign stddef stdio stpcpy strftime strtoimax symlink sys_stat sys_time time time_r time_rz timegm timer-time timespec-add timespec-sub update-copyright utimens vla warnings
 
 
 MOSTLYCLEANFILES += core *.stackdump
@@ -905,7 +905,6 @@ gl_GNULIB_ENABLED_getdtablesize = @gl_GNULIB_ENABLED_getdtablesize@
 gl_GNULIB_ENABLED_getgroups = @gl_GNULIB_ENABLED_getgroups@
 gl_GNULIB_ENABLED_secure_getenv = @gl_GNULIB_ENABLED_secure_getenv@
 gl_GNULIB_ENABLED_strtoll = @gl_GNULIB_ENABLED_strtoll@
-gl_GNULIB_ENABLED_strtoull = @gl_GNULIB_ENABLED_strtoull@
 gl_GNULIB_ENABLED_tempname = @gl_GNULIB_ENABLED_tempname@
 gl_LIBOBJS = @gl_LIBOBJS@
 gl_LTLIBOBJS = @gl_LTLIBOBJS@
@@ -2507,30 +2506,6 @@ EXTRA_libgnu_a_SOURCES += strtol.c strtoll.c
 endif
 ## end   gnulib module strtoll
 
-## begin gnulib module strtoull
-ifeq (,$(OMIT_GNULIB_MODULE_strtoull))
-
-ifneq (,$(gl_GNULIB_ENABLED_strtoull))
-
-endif
-EXTRA_DIST += strtol.c strtoul.c strtoull.c
-
-EXTRA_libgnu_a_SOURCES += strtol.c strtoul.c strtoull.c
-
-endif
-## end   gnulib module strtoull
-
-## begin gnulib module strtoumax
-ifeq (,$(OMIT_GNULIB_MODULE_strtoumax))
-
-
-EXTRA_DIST += strtoimax.c strtoumax.c
-
-EXTRA_libgnu_a_SOURCES += strtoimax.c strtoumax.c
-
-endif
-## end   gnulib module strtoumax
-
 ## begin gnulib module symlink
 ifeq (,$(OMIT_GNULIB_MODULE_symlink))
 
diff --git a/lib/strtoul.c b/lib/strtoul.c
deleted file mode 100644
index c4974e069e5..00000000000
--- a/lib/strtoul.c
+++ /dev/null
@@ -1,19 +0,0 @@
-/* Copyright (C) 1991, 1997, 2009-2017 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-
-   This program is free software: you can redistribute it and/or modify
-   it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 3 of the License, or
-   (at your option) any later version.
-
-   This program is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-   GNU General Public License for more details.
-
-   You should have received a copy of the GNU General Public License
-   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
-
-#define UNSIGNED        1
-
-#include "strtol.c"
diff --git a/lib/strtoull.c b/lib/strtoull.c
deleted file mode 100644
index 51ae3acb03c..00000000000
--- a/lib/strtoull.c
+++ /dev/null
@@ -1,26 +0,0 @@
-/* Function to parse an 'unsigned long long int' from text.
-   Copyright (C) 1995-1997, 1999, 2009-2017 Free Software Foundation, Inc.
-   NOTE: The canonical source of this file is maintained with the GNU C
-   Library.  Bugs can be reported to bug-glibc@gnu.org.
-
-   This program is free software: you can redistribute it and/or modify it
-   under the terms of the GNU General Public License as published by the
-   Free Software Foundation; either version 3 of the License, or any
-   later version.
-
-   This program is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-   GNU General Public License for more details.
-
-   You should have received a copy of the GNU General Public License
-   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
-
-#define QUAD 1
-
-#include "strtoul.c"
-
-#ifdef _LIBC
-strong_alias (__strtoull_internal, __strtouq_internal)
-weak_alias (strtoull, strtouq)
-#endif
diff --git a/lib/strtoumax.c b/lib/strtoumax.c
deleted file mode 100644
index dc395d626ab..00000000000
--- a/lib/strtoumax.c
+++ /dev/null
@@ -1,2 +0,0 @@
-#define UNSIGNED 1
-#include "strtoimax.c"
diff --git a/m4/gnulib-comp.m4 b/m4/gnulib-comp.m4
index 3f196d4f1de..8f53a990e34 100644
--- a/m4/gnulib-comp.m4
+++ b/m4/gnulib-comp.m4
@@ -140,8 +140,6 @@ AC_DEFUN([gl_EARLY],
   # Code from module string:
   # Code from module strtoimax:
   # Code from module strtoll:
-  # Code from module strtoull:
-  # Code from module strtoumax:
   # Code from module symlink:
   # Code from module sys_select:
   # Code from module sys_stat:
@@ -364,12 +362,6 @@ AC_DEFUN([gl_INIT],
     gl_PREREQ_STRTOIMAX
   fi
   gl_INTTYPES_MODULE_INDICATOR([strtoimax])
-  gl_FUNC_STRTOUMAX
-  if test $HAVE_DECL_STRTOUMAX = 0 || test $REPLACE_STRTOUMAX = 1; then
-    AC_LIBOBJ([strtoumax])
-    gl_PREREQ_STRTOUMAX
-  fi
-  gl_INTTYPES_MODULE_INDICATOR([strtoumax])
   gl_FUNC_SYMLINK
   if test $HAVE_SYMLINK = 0 || test $REPLACE_SYMLINK = 1; then
     AC_LIBOBJ([symlink])
@@ -420,7 +412,6 @@ AC_DEFUN([gl_INIT],
   gl_gnulib_enabled_6099e9737f757db36c47fa9d9f02e88c=false
   gl_gnulib_enabled_secure_getenv=false
   gl_gnulib_enabled_strtoll=false
-  gl_gnulib_enabled_strtoull=false
   gl_gnulib_enabled_tempname=false
   gl_gnulib_enabled_682e609604ccaac6be382e4ee3a4eaec=false
   func_gl_gnulib_m4code_260941c0e5dc67ec9e87d1fb321c300b ()
@@ -569,18 +560,6 @@ AC_DEFUN([gl_INIT],
       gl_gnulib_enabled_strtoll=true
     fi
   }
-  func_gl_gnulib_m4code_strtoull ()
-  {
-    if ! $gl_gnulib_enabled_strtoull; then
-      gl_FUNC_STRTOULL
-      if test $HAVE_STRTOULL = 0; then
-        AC_LIBOBJ([strtoull])
-        gl_PREREQ_STRTOULL
-      fi
-      gl_STDLIB_MODULE_INDICATOR([strtoull])
-      gl_gnulib_enabled_strtoull=true
-    fi
-  }
   func_gl_gnulib_m4code_tempname ()
   {
     if ! $gl_gnulib_enabled_tempname; then
@@ -649,9 +628,6 @@ AC_DEFUN([gl_INIT],
   if { test $HAVE_DECL_STRTOIMAX = 0 || test $REPLACE_STRTOIMAX = 1; } && test $ac_cv_type_long_long_int = yes; then
     func_gl_gnulib_m4code_strtoll
   fi
-  if { test $HAVE_DECL_STRTOUMAX = 0 || test $REPLACE_STRTOUMAX = 1; } && test $ac_cv_type_unsigned_long_long_int = yes; then
-    func_gl_gnulib_m4code_strtoull
-  fi
   if test $HAVE_TIMEGM = 0 || test $REPLACE_TIMEGM = 1; then
     func_gl_gnulib_m4code_5264294aa0a5557541b53c8c741f7f31
   fi
@@ -670,7 +646,6 @@ AC_DEFUN([gl_INIT],
   AM_CONDITIONAL([gl_GNULIB_ENABLED_6099e9737f757db36c47fa9d9f02e88c], [$gl_gnulib_enabled_6099e9737f757db36c47fa9d9f02e88c])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_secure_getenv], [$gl_gnulib_enabled_secure_getenv])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_strtoll], [$gl_gnulib_enabled_strtoll])
-  AM_CONDITIONAL([gl_GNULIB_ENABLED_strtoull], [$gl_gnulib_enabled_strtoull])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_tempname], [$gl_gnulib_enabled_tempname])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_682e609604ccaac6be382e4ee3a4eaec], [$gl_gnulib_enabled_682e609604ccaac6be382e4ee3a4eaec])
   # End of code from modules
@@ -940,9 +915,6 @@ AC_DEFUN([gl_FILE_LIST], [
   lib/strtoimax.c
   lib/strtol.c
   lib/strtoll.c
-  lib/strtoul.c
-  lib/strtoull.c
-  lib/strtoumax.c
   lib/symlink.c
   lib/sys_select.in.h
   lib/sys_stat.in.h
@@ -1051,8 +1023,6 @@ AC_DEFUN([gl_FILE_LIST], [
   m4/string_h.m4
   m4/strtoimax.m4
   m4/strtoll.m4
-  m4/strtoull.m4
-  m4/strtoumax.m4
   m4/symlink.m4
   m4/sys_select_h.m4
   m4/sys_socket_h.m4
diff --git a/m4/strtoull.m4 b/m4/strtoull.m4
deleted file mode 100644
index c6b215072b6..00000000000
--- a/m4/strtoull.m4
+++ /dev/null
@@ -1,24 +0,0 @@
-# strtoull.m4 serial 7
-dnl Copyright (C) 2002, 2004, 2006, 2008-2017 Free Software Foundation, Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-
-AC_DEFUN([gl_FUNC_STRTOULL],
-[
-  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
-  dnl We don't need (and can't compile) the replacement strtoull
-  dnl unless the type 'unsigned long long int' exists.
-  AC_REQUIRE([AC_TYPE_UNSIGNED_LONG_LONG_INT])
-  if test "$ac_cv_type_unsigned_long_long_int" = yes; then
-    AC_CHECK_FUNCS([strtoull])
-    if test $ac_cv_func_strtoull = no; then
-      HAVE_STRTOULL=0
-    fi
-  fi
-])
-
-# Prerequisites of lib/strtoull.c.
-AC_DEFUN([gl_PREREQ_STRTOULL], [
-  :
-])
diff --git a/m4/strtoumax.m4 b/m4/strtoumax.m4
deleted file mode 100644
index 43ef5b5abbf..00000000000
--- a/m4/strtoumax.m4
+++ /dev/null
@@ -1,28 +0,0 @@
-# strtoumax.m4 serial 12
-dnl Copyright (C) 2002-2004, 2006, 2009-2017 Free Software Foundation, Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-
-AC_DEFUN([gl_FUNC_STRTOUMAX],
-[
-  AC_REQUIRE([gl_INTTYPES_H_DEFAULTS])
-
-  dnl On OSF/1 5.1 with cc, this function is declared but not defined.
-  AC_CHECK_FUNCS_ONCE([strtoumax])
-  AC_CHECK_DECLS_ONCE([strtoumax])
-  if test "$ac_cv_have_decl_strtoumax" = yes; then
-    if test "$ac_cv_func_strtoumax" != yes; then
-      # HP-UX 11.11 has "#define strtoimax(...) ..." but no function.
-      REPLACE_STRTOUMAX=1
-    fi
-  else
-    HAVE_DECL_STRTOUMAX=0
-  fi
-])
-
-# Prerequisites of lib/strtoumax.c.
-AC_DEFUN([gl_PREREQ_STRTOUMAX], [
-  AC_CHECK_DECLS([strtoull])
-  AC_REQUIRE([AC_TYPE_UNSIGNED_LONG_LONG_INT])
-])
diff --git a/src/editfns.c b/src/editfns.c
index 98187df5d97..1dbae8f5d4b 100644
--- a/src/editfns.c
+++ b/src/editfns.c
@@ -3851,6 +3851,23 @@ usage: (propertize STRING &rest PROPERTIES)  */)
   return string;
 }
 
+/* Convert the prefix of STR from ASCII decimal digits to a number.
+   Set *STR_END to the address of the first non-digit.  Return the
+   number, or PTRDIFF_MAX on overflow.  Return 0 if there is no number.
+   This is like strtol for ptrdiff_t and base 10 and C locale,
+   except without negative numbers or errno.  */
+
+static ptrdiff_t
+str2num (char *str, char **str_end)
+{
+  ptrdiff_t n = 0;
+  for (; c_isdigit (*str); str++)
+    if (INT_MULTIPLY_WRAPV (n, 10, &n) || INT_ADD_WRAPV (n, *str - '0', &n))
+      n = PTRDIFF_MAX;
+  *str_end = str;
+  return n;
+}
+
 DEFUN ("format", Fformat, Sformat, 1, MANY, 0,
        doc: /* Format a string out of a format-string and arguments.
 The first argument is a format control string.
@@ -4057,17 +4074,16 @@ styled_format (ptrdiff_t nargs, Lisp_Object *args, bool message)
 	     digits to print after the '.' for floats, or the max.
 	     number of chars to print from a string.  */
 
-	  uintmax_t num;
+	  ptrdiff_t num;
 	  char *num_end;
 	  if (c_isdigit (*format))
 	    {
-	      num = strtoumax (format, &num_end, 10);
+	      num = str2num (format, &num_end);
 	      if (*num_end == '$')
 		{
 		  if (num == 0)
 		    error ("Invalid format field number 0");
-		  n = min (num, PTRDIFF_MAX);
-		  n--;
+		  n = num - 1;
 		  format = num_end + 1;
 		}
 	    }
@@ -4095,15 +4111,15 @@ styled_format (ptrdiff_t nargs, Lisp_Object *args, bool message)
 	  space_flag &= ! plus_flag;
 	  zero_flag &= ! minus_flag;
 
-	  num = strtoumax (format, &num_end, 10);
+	  num = str2num (format, &num_end);
 	  if (max_bufsize <= num)
 	    string_overflow ();
 	  ptrdiff_t field_width = num;
 
 	  bool precision_given = *num_end == '.';
-	  uintmax_t precision = (precision_given
-				 ? strtoumax (num_end + 1, &num_end, 10)
-				 : UINTMAX_MAX);
+	  ptrdiff_t precision = (precision_given
+				 ? str2num (num_end + 1, &num_end)
+				 : PTRDIFF_MAX);
 	  format = num_end;
 
 	  if (format == end)
@@ -4176,7 +4192,7 @@ styled_format (ptrdiff_t nargs, Lisp_Object *args, bool message)
 	      /* handle case (precision[n] >= 0) */
 
 	      ptrdiff_t prec = -1;
-	      if (precision_given && precision <= TYPE_MAXIMUM (ptrdiff_t))
+	      if (precision_given)
 		prec = precision;
 
 	      /* lisp_string_width ignores a precision of 0, but GNU
@@ -4424,8 +4440,9 @@ styled_format (ptrdiff_t nargs, Lisp_Object *args, bool message)
 		 padding and excess precision.  Deal with excess precision
 		 first.  This happens only when the format specifies
 		 ridiculously large precision.  */
-	      uintmax_t excess_precision = precision - prec;
-	      uintmax_t leading_zeros = 0, trailing_zeros = 0;
+	      ptrdiff_t excess_precision
+		= precision_given ? precision - prec : 0;
+	      ptrdiff_t leading_zeros = 0, trailing_zeros = 0;
 	      if (excess_precision)
 		{
 		  if (float_conversion)
@@ -4451,7 +4468,9 @@ styled_format (ptrdiff_t nargs, Lisp_Object *args, bool message)
 
 	      /* Compute the total bytes needed for this item, including
 		 excess precision and padding.  */
-	      uintmax_t numwidth = sprintf_bytes + excess_precision;
+	      ptrdiff_t numwidth;
+	      if (INT_ADD_WRAPV (sprintf_bytes, excess_precision, &numwidth))
+		numwidth = PTRDIFF_MAX;
 	      ptrdiff_t padding
 		= numwidth < field_width ? field_width - numwidth : 0;
 	      if (max_bufsize - sprintf_bytes <= excess_precision
diff --git a/src/lread.c b/src/lread.c
index 368b86e8189..f8493982c67 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -3495,25 +3495,18 @@ substitute_in_interval (INTERVAL interval, Lisp_Object arg)
 }
 
 
-#define LEAD_INT 1
-#define DOT_CHAR 2
-#define TRAIL_INT 4
-#define E_EXP 16
-
-
-/* Convert STRING to a number, assuming base BASE.  Return a fixnum if CP has
-   integer syntax and fits in a fixnum, else return the nearest float if CP has
-   either floating point or integer syntax and BASE is 10, else return nil.  If
-   IGNORE_TRAILING, consider just the longest prefix of CP that has
-   valid floating point syntax.  Signal an overflow if BASE is not 10 and the
-   number has integer syntax but does not fit.  */
+/* Convert STRING to a number, assuming base BASE.  Return a fixnum if
+   STRING has integer syntax and fits in a fixnum, else return the
+   nearest float if STRING has either floating point or integer syntax
+   and BASE is 10, else return nil.  If IGNORE_TRAILING, consider just
+   the longest prefix of STRING that has valid floating point syntax.
+   Signal an overflow if BASE is not 10 and the number has integer
+   syntax but does not fit.  */
 
 Lisp_Object
 string_to_number (char const *string, int base, bool ignore_trailing)
 {
-  int state;
   char const *cp = string;
-  int leading_digit;
   bool float_syntax = 0;
   double value = 0;
 
@@ -3525,15 +3518,23 @@ string_to_number (char const *string, int base, bool ignore_trailing)
   bool signedp = negative || *cp == '+';
   cp += signedp;
 
-  state = 0;
-
-  leading_digit = digit_to_number (*cp, base);
+  enum { INTOVERFLOW = 1, LEAD_INT = 2, DOT_CHAR = 4, TRAIL_INT = 8,
+	 E_EXP = 16 };
+  int state = 0;
+  int leading_digit = digit_to_number (*cp, base);
+  uintmax_t n = leading_digit;
   if (leading_digit >= 0)
     {
       state |= LEAD_INT;
-      do
-	++cp;
-      while (digit_to_number (*cp, base) >= 0);
+      for (int digit; 0 <= (digit = digit_to_number (*++cp, base)); )
+	{
+	  if (INT_MULTIPLY_OVERFLOW (n, base))
+	    state |= INTOVERFLOW;
+	  n *= base;
+	  if (INT_ADD_OVERFLOW (n, digit))
+	    state |= INTOVERFLOW;
+	  n += digit;
+	}
     }
   if (*cp == '.')
     {
@@ -3583,32 +3584,22 @@ string_to_number (char const *string, int base, bool ignore_trailing)
 	}
 
       float_syntax = ((state & (DOT_CHAR|TRAIL_INT)) == (DOT_CHAR|TRAIL_INT)
-		      || state == (LEAD_INT|E_EXP));
+		      || (state & ~INTOVERFLOW) == (LEAD_INT|E_EXP));
     }
 
   /* Return nil if the number uses invalid syntax.  If IGNORE_TRAILING, accept
      any prefix that matches.  Otherwise, the entire string must match.  */
   if (! (ignore_trailing
 	 ? ((state & LEAD_INT) != 0 || float_syntax)
-	 : (!*cp && ((state & ~DOT_CHAR) == LEAD_INT || float_syntax))))
+	 : (!*cp && ((state & ~(INTOVERFLOW | DOT_CHAR)) == LEAD_INT
+		     || float_syntax))))
     return Qnil;
 
   /* If the number uses integer and not float syntax, and is in C-language
      range, use its value, preferably as a fixnum.  */
   if (leading_digit >= 0 && ! float_syntax)
     {
-      uintmax_t n;
-
-      /* Fast special case for single-digit integers.  This also avoids a
-	 glitch when BASE is 16 and IGNORE_TRAILING, because in that
-	 case some versions of strtoumax accept numbers like "0x1" that Emacs
-	 does not allow.  */
-      if (digit_to_number (string[signedp + 1], base) < 0)
-	return make_number (negative ? -leading_digit : leading_digit);
-
-      errno = 0;
-      n = strtoumax (string + signedp, NULL, base);
-      if (errno == ERANGE)
+      if (state & INTOVERFLOW)
 	{
 	  /* Unfortunately there's no simple and accurate way to convert
 	     non-base-10 numbers that are out of C-language range.  */