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* [gcc r12-6117] Fortran: speed up decimal output of integers
@ 2021-12-26 11:00 Franथईois-Xavier Coudert
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From: Franथईois-Xavier Coudert @ 2021-12-26 11:00 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:9525c26bf19318bed72d3bc3b99dceac5217102f
commit r12-6117-g9525c26bf19318bed72d3bc3b99dceac5217102f
Author: Francois-Xavier Coudert <fxcoudert@gmail.com>
Date: Sun Dec 26 11:59:14 2021 +0100
Fortran: speed up decimal output of integers
libgfortran/ChangeLog:
PR libfortran/98076
* runtime/string.c (itoa64, itoa64_pad19): New helper functions.
(gfc_itoa): On targets with 128-bit integers, call fast
64-bit functions to avoid many slow divisions.
gcc/testsuite/ChangeLog:
PR libfortran/98076
* gfortran.dg/pr98076.f90: New test.
Diff:
---
gcc/testsuite/gfortran.dg/pr98076.f90 | 293 ++++++++++++++++++++++++++++++++++
libgfortran/runtime/string.c | 65 +++++++-
2 files changed, 353 insertions(+), 5 deletions(-)
diff --git a/gcc/testsuite/gfortran.dg/pr98076.f90 b/gcc/testsuite/gfortran.dg/pr98076.f90
new file mode 100644
index 00000000000..d1288a41fef
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr98076.f90
@@ -0,0 +1,293 @@
+! { dg-do run }
+! { dg-require-effective-target fortran_large_int }
+!
+! Check that we can print large integer values
+
+program test
+ implicit none
+ ! 128-bit integer kind
+ integer, parameter :: k = selected_int_kind(38)
+
+ character(len=39) :: s
+ character(len=100) :: buffer
+ integer(kind=k) :: n
+ integer :: i
+
+ ! Random checks
+ do i = 1, 1000
+ call random_digits(s)
+ read(s,*) n
+ write(buffer,'(I0.38)') n
+ print *, s
+ print *, buffer
+ if (adjustl(buffer) /= adjustl(s)) stop 2
+ end do
+
+ ! Systematic check
+ call check(0_k, "0")
+ call check(1_k, "1")
+ call check(9_k, "9")
+ call check(10_k, "10")
+ call check(11_k, "11")
+ call check(99_k, "99")
+ call check(100_k, "100")
+ call check(101_k, "101")
+ call check(999_k, "999")
+ call check(1000_k, "1000")
+ call check(1001_k, "1001")
+ call check(9999_k, "9999")
+ call check(10000_k, "10000")
+ call check(10001_k, "10001")
+ call check(99999_k, "99999")
+ call check(100000_k, "100000")
+ call check(100001_k, "100001")
+ call check(999999_k, "999999")
+ call check(1000000_k, "1000000")
+ call check(1000001_k, "1000001")
+ call check(9999999_k, "9999999")
+ call check(10000000_k, "10000000")
+ call check(10000001_k, "10000001")
+ call check(99999999_k, "99999999")
+ call check(100000000_k, "100000000")
+ call check(100000001_k, "100000001")
+ call check(999999999_k, "999999999")
+ call check(1000000000_k, "1000000000")
+ call check(1000000001_k, "1000000001")
+ call check(9999999999_k, "9999999999")
+ call check(10000000000_k, "10000000000")
+ call check(10000000001_k, "10000000001")
+ call check(99999999999_k, "99999999999")
+ call check(100000000000_k, "100000000000")
+ call check(100000000001_k, "100000000001")
+ call check(999999999999_k, "999999999999")
+ call check(1000000000000_k, "1000000000000")
+ call check(1000000000001_k, "1000000000001")
+ call check(9999999999999_k, "9999999999999")
+ call check(10000000000000_k, "10000000000000")
+ call check(10000000000001_k, "10000000000001")
+ call check(99999999999999_k, "99999999999999")
+ call check(100000000000000_k, "100000000000000")
+ call check(100000000000001_k, "100000000000001")
+ call check(999999999999999_k, "999999999999999")
+ call check(1000000000000000_k, "1000000000000000")
+ call check(1000000000000001_k, "1000000000000001")
+ call check(9999999999999999_k, "9999999999999999")
+ call check(10000000000000000_k, "10000000000000000")
+ call check(10000000000000001_k, "10000000000000001")
+ call check(99999999999999999_k, "99999999999999999")
+ call check(100000000000000000_k, "100000000000000000")
+ call check(100000000000000001_k, "100000000000000001")
+ call check(999999999999999999_k, "999999999999999999")
+ call check(1000000000000000000_k, "1000000000000000000")
+ call check(1000000000000000001_k, "1000000000000000001")
+ call check(9999999999999999999_k, "9999999999999999999")
+ call check(10000000000000000000_k, "10000000000000000000")
+ call check(10000000000000000001_k, "10000000000000000001")
+ call check(99999999999999999999_k, "99999999999999999999")
+ call check(100000000000000000000_k, "100000000000000000000")
+ call check(100000000000000000001_k, "100000000000000000001")
+ call check(999999999999999999999_k, "999999999999999999999")
+ call check(1000000000000000000000_k, "1000000000000000000000")
+ call check(1000000000000000000001_k, "1000000000000000000001")
+ call check(9999999999999999999999_k, "9999999999999999999999")
+ call check(10000000000000000000000_k, "10000000000000000000000")
+ call check(10000000000000000000001_k, "10000000000000000000001")
+ call check(99999999999999999999999_k, "99999999999999999999999")
+ call check(100000000000000000000000_k, "100000000000000000000000")
+ call check(100000000000000000000001_k, "100000000000000000000001")
+ call check(999999999999999999999999_k, "999999999999999999999999")
+ call check(1000000000000000000000000_k, "1000000000000000000000000")
+ call check(1000000000000000000000001_k, "1000000000000000000000001")
+ call check(9999999999999999999999999_k, "9999999999999999999999999")
+ call check(10000000000000000000000000_k, "10000000000000000000000000")
+ call check(10000000000000000000000001_k, "10000000000000000000000001")
+ call check(99999999999999999999999999_k, "99999999999999999999999999")
+ call check(100000000000000000000000000_k, "100000000000000000000000000")
+ call check(100000000000000000000000001_k, "100000000000000000000000001")
+ call check(999999999999999999999999999_k, "999999999999999999999999999")
+ call check(1000000000000000000000000000_k, "1000000000000000000000000000")
+ call check(1000000000000000000000000001_k, "1000000000000000000000000001")
+ call check(9999999999999999999999999999_k, "9999999999999999999999999999")
+ call check(10000000000000000000000000000_k, "10000000000000000000000000000")
+ call check(10000000000000000000000000001_k, "10000000000000000000000000001")
+ call check(99999999999999999999999999999_k, "99999999999999999999999999999")
+ call check(100000000000000000000000000000_k, "100000000000000000000000000000")
+ call check(100000000000000000000000000001_k, "100000000000000000000000000001")
+ call check(999999999999999999999999999999_k, "999999999999999999999999999999")
+ call check(1000000000000000000000000000000_k, "1000000000000000000000000000000")
+ call check(1000000000000000000000000000001_k, "1000000000000000000000000000001")
+ call check(9999999999999999999999999999999_k, "9999999999999999999999999999999")
+ call check(10000000000000000000000000000000_k, "10000000000000000000000000000000")
+ call check(10000000000000000000000000000001_k, "10000000000000000000000000000001")
+ call check(99999999999999999999999999999999_k, "99999999999999999999999999999999")
+ call check(100000000000000000000000000000000_k, "100000000000000000000000000000000")
+ call check(100000000000000000000000000000001_k, "100000000000000000000000000000001")
+ call check(999999999999999999999999999999999_k, "999999999999999999999999999999999")
+ call check(1000000000000000000000000000000000_k, "1000000000000000000000000000000000")
+ call check(1000000000000000000000000000000001_k, "1000000000000000000000000000000001")
+ call check(9999999999999999999999999999999999_k, "9999999999999999999999999999999999")
+ call check(10000000000000000000000000000000000_k, "10000000000000000000000000000000000")
+ call check(10000000000000000000000000000000001_k, "10000000000000000000000000000000001")
+ call check(99999999999999999999999999999999999_k, "99999999999999999999999999999999999")
+ call check(100000000000000000000000000000000000_k, "100000000000000000000000000000000000")
+ call check(100000000000000000000000000000000001_k, "100000000000000000000000000000000001")
+ call check(999999999999999999999999999999999999_k, "999999999999999999999999999999999999")
+ call check(1000000000000000000000000000000000000_k, "1000000000000000000000000000000000000")
+ call check(1000000000000000000000000000000000001_k, "1000000000000000000000000000000000001")
+ call check(9999999999999999999999999999999999999_k, "9999999999999999999999999999999999999")
+ call check(10000000000000000000000000000000000000_k, "10000000000000000000000000000000000000")
+ call check(10000000000000000000000000000000000001_k, "10000000000000000000000000000000000001")
+ call check(99999999999999999999999999999999999999_k, "99999999999999999999999999999999999999")
+ call check(100000000000000000000000000000000000000_k, "100000000000000000000000000000000000000")
+ call check(100000000000000000000000000000000000001_k, "100000000000000000000000000000000000001")
+ call check(109999999999999999999999999999999999999_k, "109999999999999999999999999999999999999")
+
+ call check(-1_k, "-1")
+ call check(-9_k, "-9")
+ call check(-10_k, "-10")
+ call check(-11_k, "-11")
+ call check(-99_k, "-99")
+ call check(-100_k, "-100")
+ call check(-101_k, "-101")
+ call check(-999_k, "-999")
+ call check(-1000_k, "-1000")
+ call check(-1001_k, "-1001")
+ call check(-9999_k, "-9999")
+ call check(-10000_k, "-10000")
+ call check(-10001_k, "-10001")
+ call check(-99999_k, "-99999")
+ call check(-100000_k, "-100000")
+ call check(-100001_k, "-100001")
+ call check(-999999_k, "-999999")
+ call check(-1000000_k, "-1000000")
+ call check(-1000001_k, "-1000001")
+ call check(-9999999_k, "-9999999")
+ call check(-10000000_k, "-10000000")
+ call check(-10000001_k, "-10000001")
+ call check(-99999999_k, "-99999999")
+ call check(-100000000_k, "-100000000")
+ call check(-100000001_k, "-100000001")
+ call check(-999999999_k, "-999999999")
+ call check(-1000000000_k, "-1000000000")
+ call check(-1000000001_k, "-1000000001")
+ call check(-9999999999_k, "-9999999999")
+ call check(-10000000000_k, "-10000000000")
+ call check(-10000000001_k, "-10000000001")
+ call check(-99999999999_k, "-99999999999")
+ call check(-100000000000_k, "-100000000000")
+ call check(-100000000001_k, "-100000000001")
+ call check(-999999999999_k, "-999999999999")
+ call check(-1000000000000_k, "-1000000000000")
+ call check(-1000000000001_k, "-1000000000001")
+ call check(-9999999999999_k, "-9999999999999")
+ call check(-10000000000000_k, "-10000000000000")
+ call check(-10000000000001_k, "-10000000000001")
+ call check(-99999999999999_k, "-99999999999999")
+ call check(-100000000000000_k, "-100000000000000")
+ call check(-100000000000001_k, "-100000000000001")
+ call check(-999999999999999_k, "-999999999999999")
+ call check(-1000000000000000_k, "-1000000000000000")
+ call check(-1000000000000001_k, "-1000000000000001")
+ call check(-9999999999999999_k, "-9999999999999999")
+ call check(-10000000000000000_k, "-10000000000000000")
+ call check(-10000000000000001_k, "-10000000000000001")
+ call check(-99999999999999999_k, "-99999999999999999")
+ call check(-100000000000000000_k, "-100000000000000000")
+ call check(-100000000000000001_k, "-100000000000000001")
+ call check(-999999999999999999_k, "-999999999999999999")
+ call check(-1000000000000000000_k, "-1000000000000000000")
+ call check(-1000000000000000001_k, "-1000000000000000001")
+ call check(-9999999999999999999_k, "-9999999999999999999")
+ call check(-10000000000000000000_k, "-10000000000000000000")
+ call check(-10000000000000000001_k, "-10000000000000000001")
+ call check(-99999999999999999999_k, "-99999999999999999999")
+ call check(-100000000000000000000_k, "-100000000000000000000")
+ call check(-100000000000000000001_k, "-100000000000000000001")
+ call check(-999999999999999999999_k, "-999999999999999999999")
+ call check(-1000000000000000000000_k, "-1000000000000000000000")
+ call check(-1000000000000000000001_k, "-1000000000000000000001")
+ call check(-9999999999999999999999_k, "-9999999999999999999999")
+ call check(-10000000000000000000000_k, "-10000000000000000000000")
+ call check(-10000000000000000000001_k, "-10000000000000000000001")
+ call check(-99999999999999999999999_k, "-99999999999999999999999")
+ call check(-100000000000000000000000_k, "-100000000000000000000000")
+ call check(-100000000000000000000001_k, "-100000000000000000000001")
+ call check(-999999999999999999999999_k, "-999999999999999999999999")
+ call check(-1000000000000000000000000_k, "-1000000000000000000000000")
+ call check(-1000000000000000000000001_k, "-1000000000000000000000001")
+ call check(-9999999999999999999999999_k, "-9999999999999999999999999")
+ call check(-10000000000000000000000000_k, "-10000000000000000000000000")
+ call check(-10000000000000000000000001_k, "-10000000000000000000000001")
+ call check(-99999999999999999999999999_k, "-99999999999999999999999999")
+ call check(-100000000000000000000000000_k, "-100000000000000000000000000")
+ call check(-100000000000000000000000001_k, "-100000000000000000000000001")
+ call check(-999999999999999999999999999_k, "-999999999999999999999999999")
+ call check(-1000000000000000000000000000_k, "-1000000000000000000000000000")
+ call check(-1000000000000000000000000001_k, "-1000000000000000000000000001")
+ call check(-9999999999999999999999999999_k, "-9999999999999999999999999999")
+ call check(-10000000000000000000000000000_k, "-10000000000000000000000000000")
+ call check(-10000000000000000000000000001_k, "-10000000000000000000000000001")
+ call check(-99999999999999999999999999999_k, "-99999999999999999999999999999")
+ call check(-100000000000000000000000000000_k, "-100000000000000000000000000000")
+ call check(-100000000000000000000000000001_k, "-100000000000000000000000000001")
+ call check(-999999999999999999999999999999_k, "-999999999999999999999999999999")
+ call check(-1000000000000000000000000000000_k, "-1000000000000000000000000000000")
+ call check(-1000000000000000000000000000001_k, "-1000000000000000000000000000001")
+ call check(-9999999999999999999999999999999_k, "-9999999999999999999999999999999")
+ call check(-10000000000000000000000000000000_k, "-10000000000000000000000000000000")
+ call check(-10000000000000000000000000000001_k, "-10000000000000000000000000000001")
+ call check(-99999999999999999999999999999999_k, "-99999999999999999999999999999999")
+ call check(-100000000000000000000000000000000_k, "-100000000000000000000000000000000")
+ call check(-100000000000000000000000000000001_k, "-100000000000000000000000000000001")
+ call check(-999999999999999999999999999999999_k, "-999999999999999999999999999999999")
+ call check(-1000000000000000000000000000000000_k, "-1000000000000000000000000000000000")
+ call check(-1000000000000000000000000000000001_k, "-1000000000000000000000000000000001")
+ call check(-9999999999999999999999999999999999_k, "-9999999999999999999999999999999999")
+ call check(-10000000000000000000000000000000000_k, "-10000000000000000000000000000000000")
+ call check(-10000000000000000000000000000000001_k, "-10000000000000000000000000000000001")
+ call check(-99999999999999999999999999999999999_k, "-99999999999999999999999999999999999")
+ call check(-100000000000000000000000000000000000_k, "-100000000000000000000000000000000000")
+ call check(-100000000000000000000000000000000001_k, "-100000000000000000000000000000000001")
+ call check(-999999999999999999999999999999999999_k, "-999999999999999999999999999999999999")
+ call check(-1000000000000000000000000000000000000_k, "-1000000000000000000000000000000000000")
+ call check(-1000000000000000000000000000000000001_k, "-1000000000000000000000000000000000001")
+ call check(-9999999999999999999999999999999999999_k, "-9999999999999999999999999999999999999")
+ call check(-10000000000000000000000000000000000000_k, "-10000000000000000000000000000000000000")
+ call check(-10000000000000000000000000000000000001_k, "-10000000000000000000000000000000000001")
+ call check(-99999999999999999999999999999999999999_k, "-99999999999999999999999999999999999999")
+ call check(-100000000000000000000000000000000000000_k, "-100000000000000000000000000000000000000")
+ call check(-100000000000000000000000000000000000001_k, "-100000000000000000000000000000000000001")
+ call check(-109999999999999999999999999999999999999_k, "-109999999999999999999999999999999999999")
+
+contains
+
+ subroutine check (i, str)
+ implicit none
+ integer(kind=k), intent(in), value :: i
+ character(len=*), intent(in) :: str
+
+ character(len=100) :: buffer
+ write(buffer,*) i
+ if (adjustl(buffer) /= adjustl(str)) stop 1
+ end subroutine
+
+ subroutine random_digits (str)
+ implicit none
+ integer, parameter :: l = 38
+ character(len=l+1) :: str
+ real :: r
+ integer :: i, d
+
+ str = ""
+ do i = 2, l+1
+ call random_number(r)
+ d = floor(r * 10)
+ str(i:i) = achar(48 + d)
+ end do
+
+ call random_number(r)
+ if (r > 0.5) then
+ str(1:1) = '-'
+ end if
+ end subroutine
+end
diff --git a/libgfortran/runtime/string.c b/libgfortran/runtime/string.c
index 835027a7cd6..0ccd731852a 100644
--- a/libgfortran/runtime/string.c
+++ b/libgfortran/runtime/string.c
@@ -23,6 +23,7 @@ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<http://www.gnu.org/licenses/>. */
#include "libgfortran.h"
+#include <assert.h>
#include <string.h>
#include <strings.h>
@@ -169,6 +170,38 @@ find_option (st_parameter_common *cmp, const char *s1, gfc_charlen_type s1_len,
}
+/* Fast helper function for a positive value that fits in uint64_t. */
+
+static inline char *
+itoa64 (uint64_t n, char *p)
+{
+ while (n != 0)
+ {
+ *--p = '0' + (n % 10);
+ n /= 10;
+ }
+ return p;
+}
+
+
+#if defined(HAVE_GFC_INTEGER_16)
+# define TEN19 ((GFC_UINTEGER_LARGEST) 1000000 * (GFC_UINTEGER_LARGEST) 1000000 * (GFC_UINTEGER_LARGEST) 10000000)
+
+/* Same as itoa64(), with zero padding of 19 digits. */
+
+static inline char *
+itoa64_pad19 (uint64_t n, char *p)
+{
+ for (int k = 0; k < 19; k++)
+ {
+ *--p = '0' + (n % 10);
+ n /= 10;
+ }
+ return p;
+}
+#endif
+
+
/* Integer to decimal conversion.
This function is much more restricted than the widespread (but
@@ -195,11 +228,33 @@ gfc_itoa (GFC_UINTEGER_LARGEST n, char *buffer, size_t len)
p = buffer + GFC_ITOA_BUF_SIZE - 1;
*p = '\0';
- while (n != 0)
+#if defined(HAVE_GFC_INTEGER_16)
+ /* On targets that have a 128-bit integer type, division in that type
+ is slow, because it occurs through a function call. We avoid that. */
+
+ if (n <= UINT64_MAX)
+ /* If the value fits in uint64_t, use the fast function. */
+ return itoa64 (n, p);
+ else
{
- *--p = '0' + (n % 10);
- n /= 10;
+ /* Otherwise, break down into smaller bits by division. Two calls to
+ the uint64_t function are not sufficient for all 128-bit unsigned
+ integers (we would need three calls), but they do suffice for all
+ values up to 2^127, which is the largest that Fortran can produce
+ (-HUGE(0_16)-1) with its signed integer types. */
+ static_assert(sizeof(GFC_UINTEGER_LARGEST) <= 2 * sizeof(uint64_t));
+
+ GFC_UINTEGER_LARGEST r;
+ r = n % TEN19;
+ n = n / TEN19;
+ assert (r <= UINT64_MAX);
+ p = itoa64_pad19 (r, p);
+
+ assert(n <= UINT64_MAX);
+ return itoa64 (n, p);
}
-
- return p;
+#else
+ /* On targets where the largest integer is 64-bit, just use that. */
+ return itoa64 (n, p);
+#endif
}
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