diff --git a/SOURCES/gcc8-libgfortran-default-values.patch b/SOURCES/gcc8-libgfortran-default-values.patch
new file mode 100644
index 0000000..b070abe
--- /dev/null
+++ b/SOURCES/gcc8-libgfortran-default-values.patch
@@ -0,0 +1,516 @@
+diff --git a/gcc/fortran/io.c b/gcc/fortran/io.c
+index d93dcfa..f47565c 100644
+--- a/gcc/fortran/io.c
++++ b/gcc/fortran/io.c
+@@ -909,6 +909,13 @@ data_desc:
+
+ if (u != FMT_POSINT)
+ {
++ if (flag_dec)
++ {
++ /* Assume a default width based on the variable size. */
++ saved_token = u;
++ break;
++ }
++
+ format_locus.nextc += format_string_pos;
+ gfc_error ("Positive width required in format "
+ "specifier %s at %L", token_to_string (t),
+@@ -1030,6 +1037,13 @@ data_desc:
+ goto fail;
+ if (t != FMT_ZERO && t != FMT_POSINT)
+ {
++ if (flag_dec)
++ {
++ /* Assume the default width is expected here and continue lexing. */
++ value = 0; /* It doesn't matter what we set the value to here. */
++ saved_token = t;
++ break;
++ }
+ error = nonneg_required;
+ goto syntax;
+ }
+@@ -1099,8 +1113,17 @@ data_desc:
+ goto fail;
+ if (t != FMT_ZERO && t != FMT_POSINT)
+ {
+- error = nonneg_required;
+- goto syntax;
++ if (flag_dec)
++ {
++ /* Assume the default width is expected here and continue lexing. */
++ value = 0; /* It doesn't matter what we set the value to here. */
++ saved_token = t;
++ }
++ else
++ {
++ error = nonneg_required;
++ goto syntax;
++ }
+ }
+ else if (is_input && t == FMT_ZERO)
+ {
+diff --git a/gcc/testsuite/gfortran.dg/fmt_f_default_field_width.f90 b/gcc/testsuite/gfortran.dg/fmt_f_default_field_width.f90
+new file mode 100644
+index 0000000..b087b8f
+--- /dev/null
++++ b/gcc/testsuite/gfortran.dg/fmt_f_default_field_width.f90
+@@ -0,0 +1,43 @@
++! { dg-do run }
++! { dg-options -fdec }
++!
++! Test case for the default field widths enabled by the -fdec-format-defaults flag.
++!
++! This feature is not part of any Fortran standard, but it is supported by the
++! Oracle Fortran compiler and others.
++!
++! libgfortran uses printf() internally to implement FORMAT. If you print float
++! values to a higher precision than the type can actually store, the results
++! are implementation dependent: some platforms print zeros, others print random
++! numbers. Don't depend on this behaviour in tests because they will not be
++! portable.
++
++ character(50) :: buffer
++
++ real*4 :: real_4
++ real*8 :: real_8
++ real*16 :: real_16
++ integer :: len
++
++ real_4 = 4.18
++ write(buffer, '(A, F, A)') ':',real_4,':'
++ print *,buffer
++ if (buffer.ne.": 4.1799998:") call abort
++
++ real_4 = 0.00000018
++ write(buffer, '(A, F, A)') ':',real_4,':'
++ print *,buffer
++ if (buffer.ne.": 0.0000002:") call abort
++
++ real_8 = 4.18
++ write(buffer, '(A, F, A)') ':',real_8,':'
++ print *,buffer
++ len = len_trim(buffer)
++ if (len /= 27) call abort
++
++ real_16 = 4.18
++ write(buffer, '(A, F, A)') ':',real_16,':'
++ print *,buffer
++ len = len_trim(buffer)
++ if (len /= 44) call abort
++end
+diff --git a/gcc/testsuite/gfortran.dg/fmt_g_default_field_width.f90 b/gcc/testsuite/gfortran.dg/fmt_g_default_field_width.f90
+new file mode 100644
+index 0000000..3d3a476
+--- /dev/null
++++ b/gcc/testsuite/gfortran.dg/fmt_g_default_field_width.f90
+@@ -0,0 +1,48 @@
++! { dg-do run }
++! { dg-options -fdec }
++!
++! Test case for the default field widths enabled by the -fdec-format-defaults flag.
++!
++! This feature is not part of any Fortran standard, but it is supported by the
++! Oracle Fortran compiler and others.
++!
++! libgfortran uses printf() internally to implement FORMAT. If you print float
++! values to a higher precision than the type can actually store, the results
++! are implementation dependent: some platforms print zeros, others print random
++! numbers. Don't depend on this behaviour in tests because they will not be
++! portable.
++
++ character(50) :: buffer
++
++ real*4 :: real_4
++ real*8 :: real_8
++ real*16 :: real_16
++ integer :: len
++
++ real_4 = 4.18
++ write(buffer, '(A, G, A)') ':',real_4,':'
++ print *,buffer
++ if (buffer.ne.": 4.180000 :") call abort
++
++ real_4 = 0.00000018
++ write(buffer, '(A, G, A)') ':',real_4,':'
++ print *,buffer
++ if (buffer.ne.": 0.1800000E-06:") call abort
++
++ real_4 = 18000000.4
++ write(buffer, '(A, G, A)') ':',real_4,':'
++ print *,buffer
++ if (buffer.ne.": 0.1800000E+08:") call abort
++
++ real_8 = 4.18
++ write(buffer, '(A, G, A)') ':',real_8,':'
++ print *,buffer
++ len = len_trim(buffer)
++ if (len /= 27) call abort
++
++ real_16 = 4.18
++ write(buffer, '(A, G, A)') ':',real_16,':'
++ print *,buffer
++ len = len_trim(buffer)
++ if (len /= 44) call abort
++end
+diff --git a/gcc/testsuite/gfortran.dg/fmt_i_default_field_width.f90 b/gcc/testsuite/gfortran.dg/fmt_i_default_field_width.f90
+new file mode 100644
+index 0000000..ac4e165
+--- /dev/null
++++ b/gcc/testsuite/gfortran.dg/fmt_i_default_field_width.f90
+@@ -0,0 +1,38 @@
++! { dg-do run }
++! { dg-options -fdec }
++!
++! Test case for the default field widths enabled by the -fdec-format-defaults flag.
++!
++! This feature is not part of any Fortran standard, but it is supported by the
++! Oracle Fortran compiler and others.
++
++ character(50) :: buffer
++ character(1) :: colon
++
++ integer*2 :: integer_2
++ integer*4 :: integer_4
++ integer*8 :: integer_8
++
++ write(buffer, '(A, I, A)') ':',12340,':'
++ print *,buffer
++ if (buffer.ne.": 12340:") call abort
++
++ read(buffer, '(A1, I, A1)') colon, integer_4, colon
++ if (integer_4.ne.12340) call abort
++
++ integer_2 = -99
++ write(buffer, '(A, I, A)') ':',integer_2,':'
++ print *,buffer
++ if (buffer.ne.": -99:") call abort
++
++ integer_8 = -11112222
++ write(buffer, '(A, I, A)') ':',integer_8,':'
++ print *,buffer
++ if (buffer.ne.": -11112222:") call abort
++
++! If the width is 7 and there are 7 leading zeroes, the result should be zero.
++ integer_2 = 789
++ buffer = '0000000789'
++ read(buffer, '(I)') integer_2
++ if (integer_2.ne.0) call abort
++end
+diff --git a/libgfortran/io/format.c b/libgfortran/io/format.c
+index c2abdd7..692b1ff 100644
+--- a/libgfortran/io/format.c
++++ b/libgfortran/io/format.c
+@@ -956,12 +956,33 @@ parse_format_list (st_parameter_dt *dtp, bool *seen_dd)
+ *seen_dd = true;
+ if (u != FMT_POSINT && u != FMT_ZERO)
+ {
++ if (dtp->common.flags & IOPARM_DT_DEC_EXT)
++ {
++ tail->u.real.w = DEFAULT_WIDTH;
++ tail->u.real.d = 0;
++ tail->u.real.e = -1;
++ fmt->saved_token = u;
++ break;
++ }
+ fmt->error = nonneg_required;
+ goto finished;
+ }
+ }
++ else if (u == FMT_ZERO)
++ {
++ fmt->error = posint_required;
++ goto finished;
++ }
+ else if (u != FMT_POSINT)
+ {
++ if (dtp->common.flags & IOPARM_DT_DEC_EXT)
++ {
++ tail->u.real.w = DEFAULT_WIDTH;
++ tail->u.real.d = 0;
++ tail->u.real.e = -1;
++ fmt->saved_token = u;
++ break;
++ }
+ fmt->error = posint_required;
+ goto finished;
+ }
+@@ -1099,6 +1120,13 @@ parse_format_list (st_parameter_dt *dtp, bool *seen_dd)
+ {
+ if (t != FMT_POSINT)
+ {
++ if (dtp->common.flags & IOPARM_DT_DEC_EXT)
++ {
++ tail->u.integer.w = DEFAULT_WIDTH;
++ tail->u.integer.m = -1;
++ fmt->saved_token = t;
++ break;
++ }
+ fmt->error = posint_required;
+ goto finished;
+ }
+@@ -1107,6 +1135,13 @@ parse_format_list (st_parameter_dt *dtp, bool *seen_dd)
+ {
+ if (t != FMT_ZERO && t != FMT_POSINT)
+ {
++ if (dtp->common.flags & IOPARM_DT_DEC_EXT)
++ {
++ tail->u.integer.w = DEFAULT_WIDTH;
++ tail->u.integer.m = -1;
++ fmt->saved_token = t;
++ break;
++ }
+ fmt->error = nonneg_required;
+ goto finished;
+ }
+diff --git a/libgfortran/io/io.h b/libgfortran/io/io.h
+index 5583183..d1d08e8 100644
+--- a/libgfortran/io/io.h
++++ b/libgfortran/io/io.h
+@@ -981,5 +981,55 @@ memset4 (gfc_char4_t *p, gfc_char4_t c, int k)
+ *p++ = c;
+ }
+
++/* Used in width fields to indicate that the default should be used */
++#define DEFAULT_WIDTH -1
++
++/* Defaults for certain format field descriptors. These are decided based on
++ * the type of the value being formatted.
++ *
++ * The behaviour here is modelled on the Oracle Fortran compiler. At the time
++ * of writing, the details were available at this URL:
++ *
++ * https://docs.oracle.com/cd/E19957-01/805-4939/6j4m0vnc3/index.html#z4000743746d
++ */
++
++static inline int
++default_width_for_integer (int kind)
++{
++ switch (kind)
++ {
++ case 1:
++ case 2: return 7;
++ case 4: return 12;
++ case 8: return 23;
++ case 16: return 44;
++ default: return 0;
++ }
++}
++
++static inline int
++default_width_for_float (int kind)
++{
++ switch (kind)
++ {
++ case 4: return 15;
++ case 8: return 25;
++ case 16: return 42;
++ default: return 0;
++ }
++}
++
++static inline int
++default_precision_for_float (int kind)
++{
++ switch (kind)
++ {
++ case 4: return 7;
++ case 8: return 16;
++ case 16: return 33;
++ default: return 0;
++ }
++}
++
+ #endif
+
+diff --git a/libgfortran/io/read.c b/libgfortran/io/read.c
+index 2c9de48..e911e35 100644
+--- a/libgfortran/io/read.c
++++ b/libgfortran/io/read.c
+@@ -629,6 +629,12 @@ read_decimal (st_parameter_dt *dtp, const fnode *f, char *dest, int length)
+
+ w = f->u.w;
+
++ /* This is a legacy extension, and the frontend will only allow such cases
++ * through when -fdec-format-defaults is passed.
++ */
++ if (w == DEFAULT_WIDTH)
++ w = default_width_for_integer (length);
++
+ p = read_block_form (dtp, &w);
+
+ if (p == NULL)
+diff --git a/libgfortran/io/write.c b/libgfortran/io/write.c
+index a7307a8..c8e52fb 100644
+--- a/libgfortran/io/write.c
++++ b/libgfortran/io/write.c
+@@ -684,9 +684,8 @@ write_l (st_parameter_dt *dtp, const fnode *f, char *source, int len)
+ p[wlen - 1] = (n) ? 'T' : 'F';
+ }
+
+-
+ static void
+-write_boz (st_parameter_dt *dtp, const fnode *f, const char *q, int n)
++write_boz (st_parameter_dt *dtp, const fnode *f, const char *q, int n, int len)
+ {
+ int w, m, digits, nzero, nblank;
+ char *p;
+@@ -719,6 +718,9 @@ write_boz (st_parameter_dt *dtp, const fnode *f, const char *q, int n)
+ /* Select a width if none was specified. The idea here is to always
+ print something. */
+
++ if (w == DEFAULT_WIDTH)
++ w = default_width_for_integer (len);
++
+ if (w == 0)
+ w = ((digits < m) ? m : digits);
+
+@@ -845,6 +847,8 @@ write_decimal (st_parameter_dt *dtp, const fnode *f, const char *source,
+
+ /* Select a width if none was specified. The idea here is to always
+ print something. */
++ if (w == DEFAULT_WIDTH)
++ w = default_width_for_integer (len);
+
+ if (w == 0)
+ w = ((digits < m) ? m : digits) + nsign;
+@@ -1187,13 +1191,13 @@ write_b (st_parameter_dt *dtp, const fnode *f, const char *source, int len)
+ if (len > (int) sizeof (GFC_UINTEGER_LARGEST))
+ {
+ p = btoa_big (source, itoa_buf, len, &n);
+- write_boz (dtp, f, p, n);
++ write_boz (dtp, f, p, n, len);
+ }
+ else
+ {
+ n = extract_uint (source, len);
+ p = btoa (n, itoa_buf, sizeof (itoa_buf));
+- write_boz (dtp, f, p, n);
++ write_boz (dtp, f, p, n, len);
+ }
+ }
+
+@@ -1208,13 +1212,13 @@ write_o (st_parameter_dt *dtp, const fnode *f, const char *source, int len)
+ if (len > (int) sizeof (GFC_UINTEGER_LARGEST))
+ {
+ p = otoa_big (source, itoa_buf, len, &n);
+- write_boz (dtp, f, p, n);
++ write_boz (dtp, f, p, n, len);
+ }
+ else
+ {
+ n = extract_uint (source, len);
+ p = otoa (n, itoa_buf, sizeof (itoa_buf));
+- write_boz (dtp, f, p, n);
++ write_boz (dtp, f, p, n, len);
+ }
+ }
+
+@@ -1228,13 +1232,13 @@ write_z (st_parameter_dt *dtp, const fnode *f, const char *source, int len)
+ if (len > (int) sizeof (GFC_UINTEGER_LARGEST))
+ {
+ p = ztoa_big (source, itoa_buf, len, &n);
+- write_boz (dtp, f, p, n);
++ write_boz (dtp, f, p, n, len);
+ }
+ else
+ {
+ n = extract_uint (source, len);
+ p = gfc_xtoa (n, itoa_buf, sizeof (itoa_buf));
+- write_boz (dtp, f, p, n);
++ write_boz (dtp, f, p, n, len);
+ }
+ }
+
+@@ -1504,7 +1508,7 @@ size_from_kind (st_parameter_dt *dtp, const fnode *f, int kind)
+ {
+ int size;
+
+- if (f->format == FMT_F && f->u.real.w == 0)
++ if ((f->format == FMT_F && f->u.real.w == 0) || f->u.real.w == DEFAULT_WIDTH)
+ {
+ switch (kind)
+ {
+diff --git a/libgfortran/io/write_float.def b/libgfortran/io/write_float.def
+index 7f0aa1d..73dc910 100644
+--- a/libgfortran/io/write_float.def
++++ b/libgfortran/io/write_float.def
+@@ -113,7 +113,8 @@ determine_precision (st_parameter_dt * d
+ static void
+ build_float_string (st_parameter_dt *dtp, const fnode *f, char *buffer,
+ size_t size, int nprinted, int precision, int sign_bit,
+- bool zero_flag, int npad, char *result, size_t *len)
++ bool zero_flag, int npad, int default_width, char *result,
++ size_t *len)
+ {
+ char *put;
+ char *digits;
+@@ -132,8 +133,17 @@ build_float_string (st_parameter_dt *dtp
+ sign_t sign;
+
+ ft = f->format;
+- w = f->u.real.w;
+- d = f->u.real.d;
++ if (f->u.real.w == DEFAULT_WIDTH)
++ /* This codepath can only be reached with -fdec-format-defaults. */
++ {
++ w = default_width;
++ d = precision;
++ }
++ else
++ {
++ w = f->u.real.w;
++ d = f->u.real.d;
++ }
+ p = dtp->u.p.scale_factor;
+ *len = 0;
+
+@@ -959,6 +969,11 @@ determine_en_precision (st_parameter_dt
+ int save_scale_factor;\
+ volatile GFC_REAL_ ## x temp;\
+ save_scale_factor = dtp->u.p.scale_factor;\
++ if (w == DEFAULT_WIDTH)\
++ {\
++ w = default_width;\
++ d = precision;\
++ }\
+ switch (dtp->u.p.current_unit->round_status)\
+ {\
+ case ROUND_ZERO:\
+@@ -1034,7 +1049,8 @@ determine_en_precision (st_parameter_dt
+ nprinted = FDTOA(y,precision,m);\
+ }\
+ build_float_string (dtp, &newf, buffer, size, nprinted, precision,\
+- sign_bit, zero_flag, npad, result, res_len);\
++ sign_bit, zero_flag, npad, default_width,\
++ result, res_len);\
+ dtp->u.p.scale_factor = save_scale_factor;\
+ }\
+ else\
+@@ -1044,7 +1060,8 @@ determine_en_precision (st_parameter_dt
+ else\
+ nprinted = DTOA(y,precision,m);\
+ build_float_string (dtp, f, buffer, size, nprinted, precision,\
+- sign_bit, zero_flag, npad, result, res_len);\
++ sign_bit, zero_flag, npad, default_width,\
++ result, res_len);\
+ }\
+ }\
+
+@@ -1058,6 +1075,16 @@ get_float_string (st_parameter_dt *dtp,
+ {
+ int sign_bit, nprinted;
+ bool zero_flag;
++ int default_width = 0;
++
++ if (f->u.real.w == DEFAULT_WIDTH)
++ /* This codepath can only be reached with -fdec-format-defaults. The default
++ * values are based on those used in the Oracle Fortran compiler.
++ */
++ {
++ default_width = default_width_for_float (kind);
++ precision = default_precision_for_float (kind);
++ }
+
+ switch (kind)
+ {
diff --git a/SPECS/gcc.spec b/SPECS/gcc.spec
index e029f89..5fa0be1 100644
--- a/SPECS/gcc.spec
+++ b/SPECS/gcc.spec
@@ -104,7 +104,7 @@
Summary: Various compilers (C, C++, Objective-C, ...)
Name: gcc
Version: %{gcc_version}
-Release: %{gcc_release}%{?dist}
+Release: %{gcc_release}.1%{?dist}
# libgcc, libgfortran, libgomp, libstdc++ and crtstuff have
# GCC Runtime Exception.
License: GPLv3+ and GPLv3+ with exceptions and GPLv2+ with exceptions and LGPLv2+ and BSD
@@ -284,6 +284,7 @@ Patch23: gcc8-pr96796.patch
Patch24: gcc8-pch-tweaks.patch
Patch25: gcc8-aarch64-mtune-neoverse-512tvb.patch
Patch26: gcc8-rh2028609.patch
+Patch27: gcc8-libgfortran-default-values.patch
Patch30: gcc8-rh1668903-1.patch
Patch31: gcc8-rh1668903-2.patch
@@ -869,6 +870,7 @@ to NVidia PTX capable devices if available.
%patch24 -p1 -b .pch-tweaks~
%patch25 -p1 -b .neoverse~
%patch26 -p1 -b .rh2028609~
+%patch27 -p1 -b .libgfortran-default~
%patch30 -p0 -b .rh1668903-1~
%patch31 -p0 -b .rh1668903-2~
@@ -3185,6 +3187,9 @@ fi
%endif
%changelog
+* Wed Apr 27 2022 Marek Polacek <polacek@redhat.com> 8.5.0-10.1
+- backport Default widths with -fdec-format-defaults patch (#2079578)
+
* Thu Jan 27 2022 Marek Polacek <polacek@redhat.com> 8.5.0-10
- fix typo in the cprop_hardreg patch (#2028609)