remove -gz=zlib-gnu option value

The option value is legacy and probably not used at all,
thus ignore it.

gcc/ChangeLog:

	* configure: Regenerate.
	* configure.ac: Simplify to gcc_cv_ld_compress_debug={0,1}
	and gcc_cv_as_compress_debug={0,1}.
	* doc/invoke.texi: Document the removal.
	* gcc.cc (LINK_COMPRESS_DEBUG_SPEC): Simplify and ignore
	  zlib-gnu.
	(ASM_COMPRESS_DEBUG_SPEC): Likewise.

Co-Authored-By: Fangrui Song <i@maskray.me>

4 files changed, 20 insertions, 115 deletions

diff --git a/gcc/configure b/gcc/configure
index 817d765..70a013e 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -29727,16 +29727,9 @@ else
    if $gcc_cv_as --compress-debug-sections -o conftest.o conftest.s 2>&1 | grep -i warning > /dev/null
    then
      gcc_cv_as_compress_debug=0
-   # Since binutils 2.26, gas supports --compress-debug-sections=type,
+   # Since binutils 2.26, gas supports --compress-debug-sections=zlib,
    # defaulting to the ELF gABI format.
-   elif $gcc_cv_as --compress-debug-sections=zlib-gnu -o conftest.o conftest.s > /dev/null 2>&1
-   then
-     gcc_cv_as_compress_debug=2
-     gcc_cv_as_compress_debug_option="--compress-debug-sections"
-     gcc_cv_as_no_compress_debug_option="--nocompress-debug-sections"
-   # Before binutils 2.26, gas only supported --compress-debug-options and
-   # emitted the traditional GNU format.
-   elif $gcc_cv_as --compress-debug-sections -o conftest.o conftest.s > /dev/null 2>&1
+   elif $gcc_cv_as --compress-debug-sections=zlib -o conftest.o conftest.s > /dev/null 2>&1
    then
      gcc_cv_as_compress_debug=1
      gcc_cv_as_compress_debug_option="--compress-debug-sections"
@@ -30254,48 +30247,16 @@ $as_echo "$gcc_cv_ld_eh_gc_sections_bug" >&6; }
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking linker for compressed debug sections" >&5
 $as_echo_n "checking linker for compressed debug sections... " >&6; }
-# gold/gld support compressed debug sections since binutils 2.19/2.21
-# In binutils 2.26, gld gained support for the ELF gABI format.
-if test $in_tree_ld = yes ; then
-  gcc_cv_ld_compress_debug=0
-  if test $ld_is_mold = yes; then
-    gcc_cv_ld_compress_debug=3
-    gcc_cv_ld_compress_debug_option="--compress-debug-sections"
-  elif test "$gcc_cv_gld_major_version" -eq 2 -a "$gcc_cv_gld_minor_version" -ge 19 -o "$gcc_cv_gld_major_version" -gt 2 \
-     && test $in_tree_ld_is_elf = yes && test $ld_is_gold = yes; then
-    gcc_cv_ld_compress_debug=2
-    gcc_cv_ld_compress_debug_option="--compress-debug-sections"
-  elif test "$gcc_cv_gld_major_version" -eq 2 -a "$gcc_cv_gld_minor_version" -ge 26 -o "$gcc_cv_gld_major_version" -gt 2 \
-     && test $in_tree_ld_is_elf = yes && test $ld_is_gold = no; then
-    gcc_cv_ld_compress_debug=3
-    gcc_cv_ld_compress_debug_option="--compress-debug-sections"
-  elif test "$gcc_cv_gld_major_version" -eq 2 -a "$gcc_cv_gld_minor_version" -ge 21 -o "$gcc_cv_gld_major_version" -gt 2 \
-     && test $in_tree_ld_is_elf = yes; then
+# GNU ld/gold support --compressed-debug-sections=zlib since binutils 2.26.
+if $gcc_cv_ld --help 2>&1 | grep -- '--compress-debug-sections.*\<zlib-gabi\>' > /dev/null; then
     gcc_cv_ld_compress_debug=1
-  fi
-elif echo "$ld_ver" | grep GNU > /dev/null; then
-  if test $ld_is_mold = yes; then
-    gcc_cv_ld_compress_debug=3
-    gcc_cv_ld_compress_debug_option="--compress-debug-sections"
-  elif test "$ld_vers_major" -lt 2 \
-     || test "$ld_vers_major" -eq 2 -a "$ld_vers_minor" -lt 21; then
-    gcc_cv_ld_compress_debug=0
-  elif test "$ld_vers_major" -eq 2 -a "$ld_vers_minor" -lt 26; then
-    gcc_cv_ld_compress_debug=1
-  else
-    gcc_cv_ld_compress_debug=3
-    gcc_cv_ld_compress_debug_option="--compress-debug-sections"
-  fi
-  if test $ld_is_gold = yes; then
-    gcc_cv_ld_compress_debug=2
     gcc_cv_ld_compress_debug_option="--compress-debug-sections"
-  fi
 else
   case "${target}" in
     *-*-solaris2*)
       # Introduced in Solaris 11.2.
       if $gcc_cv_ld --help 2>&1 | grep -- '-z compress-sections' > /dev/null; then
-        gcc_cv_ld_compress_debug=3
+        gcc_cv_ld_compress_debug=1
         gcc_cv_ld_compress_debug_option="-z compress-sections"
       else
         gcc_cv_ld_compress_debug=0
diff --git a/gcc/configure.ac b/gcc/configure.ac
index 59f205a1..96e10d7 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -5732,16 +5732,9 @@ gcc_GAS_CHECK_FEATURE([compressed debug sections],
    if $gcc_cv_as --compress-debug-sections -o conftest.o conftest.s 2>&1 | grep -i warning > /dev/null
    then
      gcc_cv_as_compress_debug=0
-   # Since binutils 2.26, gas supports --compress-debug-sections=type,
+   # Since binutils 2.26, gas supports --compress-debug-sections=zlib,
    # defaulting to the ELF gABI format.
-   elif $gcc_cv_as --compress-debug-sections=zlib-gnu -o conftest.o conftest.s > /dev/null 2>&1
-   then
-     gcc_cv_as_compress_debug=2
-     gcc_cv_as_compress_debug_option="--compress-debug-sections"
-     gcc_cv_as_no_compress_debug_option="--nocompress-debug-sections"
-   # Before binutils 2.26, gas only supported --compress-debug-options and
-   # emitted the traditional GNU format.
-   elif $gcc_cv_as --compress-debug-sections -o conftest.o conftest.s > /dev/null 2>&1
+   elif $gcc_cv_as --compress-debug-sections=zlib -o conftest.o conftest.s > /dev/null 2>&1
    then
      gcc_cv_as_compress_debug=1
      gcc_cv_as_compress_debug_option="--compress-debug-sections"
@@ -6130,49 +6123,17 @@ fi
 AC_MSG_RESULT($gcc_cv_ld_eh_gc_sections_bug)
 
 AC_MSG_CHECKING(linker for compressed debug sections)
-# gold/gld support compressed debug sections since binutils 2.19/2.21
-# In binutils 2.26, gld gained support for the ELF gABI format.
-if test $in_tree_ld = yes ; then
-  gcc_cv_ld_compress_debug=0
-  if test $ld_is_mold = yes; then
-    gcc_cv_ld_compress_debug=3
-    gcc_cv_ld_compress_debug_option="--compress-debug-sections"
-  elif test "$gcc_cv_gld_major_version" -eq 2 -a "$gcc_cv_gld_minor_version" -ge 19 -o "$gcc_cv_gld_major_version" -gt 2 \
-     && test $in_tree_ld_is_elf = yes && test $ld_is_gold = yes; then
-    gcc_cv_ld_compress_debug=2
-    gcc_cv_ld_compress_debug_option="--compress-debug-sections"
-  elif test "$gcc_cv_gld_major_version" -eq 2 -a "$gcc_cv_gld_minor_version" -ge 26 -o "$gcc_cv_gld_major_version" -gt 2 \
-     && test $in_tree_ld_is_elf = yes && test $ld_is_gold = no; then
-    gcc_cv_ld_compress_debug=3
-    gcc_cv_ld_compress_debug_option="--compress-debug-sections"
-  elif test "$gcc_cv_gld_major_version" -eq 2 -a "$gcc_cv_gld_minor_version" -ge 21 -o "$gcc_cv_gld_major_version" -gt 2 \
-     && test $in_tree_ld_is_elf = yes; then
+# GNU ld/gold support --compressed-debug-sections=zlib since binutils 2.26.
+if $gcc_cv_ld --help 2>&1 | grep -- '--compress-debug-sections.*\<zlib-gabi\>' > /dev/null; then
     gcc_cv_ld_compress_debug=1
-  fi
-elif echo "$ld_ver" | grep GNU > /dev/null; then
-  if test $ld_is_mold = yes; then
-    gcc_cv_ld_compress_debug=3
-    gcc_cv_ld_compress_debug_option="--compress-debug-sections"
-  elif test "$ld_vers_major" -lt 2 \
-     || test "$ld_vers_major" -eq 2 -a "$ld_vers_minor" -lt 21; then
-    gcc_cv_ld_compress_debug=0
-  elif test "$ld_vers_major" -eq 2 -a "$ld_vers_minor" -lt 26; then
-    gcc_cv_ld_compress_debug=1
-  else
-    gcc_cv_ld_compress_debug=3
-    gcc_cv_ld_compress_debug_option="--compress-debug-sections"
-  fi
-  if test $ld_is_gold = yes; then
-    gcc_cv_ld_compress_debug=2
     gcc_cv_ld_compress_debug_option="--compress-debug-sections"
-  fi
 else
 changequote(,)dnl
   case "${target}" in
     *-*-solaris2*)
       # Introduced in Solaris 11.2.
       if $gcc_cv_ld --help 2>&1 | grep -- '-z compress-sections' > /dev/null; then
-        gcc_cv_ld_compress_debug=3
+        gcc_cv_ld_compress_debug=1
         gcc_cv_ld_compress_debug_option="-z compress-sections"
       else
         gcc_cv_ld_compress_debug=0
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index aa56557..9fdcb5f 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -11077,12 +11077,11 @@ location views are enabled.
 Produce compressed debug sections in DWARF format, if that is supported.
 If @var{type} is not given, the default type depends on the capabilities
 of the assembler and linker used.  @var{type} may be one of
-@samp{none} (don't compress debug sections), @samp{zlib} (use zlib
-compression in ELF gABI format), or @samp{zlib-gnu} (use zlib
-compression in traditional GNU format).  If the linker doesn't support
-writing compressed debug sections, the option is rejected.  Otherwise,
-if the assembler does not support them, @option{-gz} is silently ignored
-when producing object files.
+@samp{none} (don't compress debug sections), or @samp{zlib} (use zlib
+compression in ELF gABI format).  If the linker doesn't support writing
+compressed debug sections, the option is rejected.  Otherwise, if the
+assembler does not support them, @option{-gz} is silently ignored when
+producing object files.
 
 @item -femit-struct-debug-baseonly
 @opindex femit-struct-debug-baseonly
diff --git a/gcc/gcc.cc b/gcc/gcc.cc
index 1584611..7578988 100644
--- a/gcc/gcc.cc
+++ b/gcc/gcc.cc
@@ -831,21 +831,11 @@ proper position among the other output files.  */
 #define LINK_COMPRESS_DEBUG_SPEC \
 	" %{gz*:%e-gz is not supported in this configuration} "
 #elif HAVE_LD_COMPRESS_DEBUG == 1
-/* GNU style on input, GNU ld options.  Reject, not useful.  */
-#define LINK_COMPRESS_DEBUG_SPEC \
-	" %{gz*:%e-gz is not supported in this configuration} "
-#elif HAVE_LD_COMPRESS_DEBUG == 2
-/* GNU style, GNU gold options.  */
-#define LINK_COMPRESS_DEBUG_SPEC \
-	" %{gz|gz=zlib-gnu:" LD_COMPRESS_DEBUG_OPTION "=zlib}" \
-	" %{gz=none:"        LD_COMPRESS_DEBUG_OPTION "=none}" \
-	" %{gz=zlib:%e-gz=zlib is not supported in this configuration} "
-#elif HAVE_LD_COMPRESS_DEBUG == 3
 /* ELF gABI style.  */
 #define LINK_COMPRESS_DEBUG_SPEC \
 	" %{gz|gz=zlib:"  LD_COMPRESS_DEBUG_OPTION "=zlib}" \
 	" %{gz=none:"	  LD_COMPRESS_DEBUG_OPTION "=none}" \
-	" %{gz=zlib-gnu:" LD_COMPRESS_DEBUG_OPTION "=zlib-gnu} "
+	" %{gz=zlib-gnu:}" /* Ignore silently zlib-gnu option value.  */
 #else
 #error Unknown value for HAVE_LD_COMPRESS_DEBUG.
 #endif
@@ -885,31 +875,25 @@ proper position among the other output files.  */
 #endif
 
 /* Assembler options for compressed debug sections.  */
-#if HAVE_LD_COMPRESS_DEBUG < 2
+#if HAVE_LD_COMPRESS_DEBUG == 0
 /* Reject if the linker cannot write compressed debug sections.  */
 #define ASM_COMPRESS_DEBUG_SPEC \
 	" %{gz*:%e-gz is not supported in this configuration} "
-#else /* HAVE_LD_COMPRESS_DEBUG >= 2 */
+#else /* HAVE_LD_COMPRESS_DEBUG >= 1 */
 #if HAVE_AS_COMPRESS_DEBUG == 0
 /* No assembler support.  Ignore silently.  */
 #define ASM_COMPRESS_DEBUG_SPEC \
 	" %{gz*:} "
 #elif HAVE_AS_COMPRESS_DEBUG == 1
-/* GNU style, GNU as options.  */
-#define ASM_COMPRESS_DEBUG_SPEC \
-	" %{gz|gz=zlib-gnu:" AS_COMPRESS_DEBUG_OPTION "}" \
-	" %{gz=none:"        AS_NO_COMPRESS_DEBUG_OPTION "}" \
-	" %{gz=zlib:%e-gz=zlib is not supported in this configuration} "
-#elif HAVE_AS_COMPRESS_DEBUG == 2
 /* ELF gABI style.  */
 #define ASM_COMPRESS_DEBUG_SPEC \
 	" %{gz|gz=zlib:"  AS_COMPRESS_DEBUG_OPTION "=zlib}" \
 	" %{gz=none:"	  AS_COMPRESS_DEBUG_OPTION "=none}" \
-	" %{gz=zlib-gnu:" AS_COMPRESS_DEBUG_OPTION "=zlib-gnu} "
+	" %{gz=zlib-gnu:}" /* Ignore silently zlib-gnu option value.  */
 #else
 #error Unknown value for HAVE_AS_COMPRESS_DEBUG.
 #endif
-#endif /* HAVE_LD_COMPRESS_DEBUG >= 2 */
+#endif /* HAVE_LD_COMPRESS_DEBUG >= 1 */
 
 /* Define ASM_DEBUG_SPEC to be a spec suitable for translating '-g'
    to the assembler, when compiling assembly sources only.  */