[Bug bootstrap/89494] Bootstrap error when using GCC 4.2.1

[pkubaj at anongoth dot pl]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89494

--- Comment #12 from Piotr Kubaj <pkubaj at anongoth dot pl> ---
This issue can be fixed with the following patches:
--- gcc/dumpfile.c.orig 2020-04-07 14:09:14 UTC
+++ gcc/dumpfile.c
@@ -2055,7 +2055,7 @@ temp_dump_context::temp_dump_context (bool forcibly_en
                                      bool forcibly_enable_dumping,
                                      dump_flags_t test_pp_flags)
 : m_context (),
-  m_saved (&dump_context ().get ())
+  m_saved(&dump_context::get())
 {
   dump_context::s_current = &m_context;
   if (forcibly_enable_optinfo)
--- libgcc/config/rs6000/t-crtstuff.orig        2020-04-07 15:17:50 UTC
+++ libgcc/config/rs6000/t-crtstuff
@@ -3,4 +3,4 @@
 # Do not build crtend.o with -Os as that can result in references to
 # out-of-line register save/restore functions, which may be unresolved
 # as crtend.o is linked after libgcc.a.  See PR45053.
-CRTSTUFF_T_CFLAGS = -msdata=none -O2 -fno-asynchronous-unwind-tables
+CRTSTUFF_T_CFLAGS = -msdata=none -O0 -fno-asynchronous-unwind-tables
--- Makefile.in.orig    2020-04-08 13:04:40 UTC
+++ Makefile.in
@@ -372,7 +372,7 @@ BUILD_PREFIX_1 = @BUILD_PREFIX_1@

 # Flags to pass to stage2 and later makes.  They are defined
 # here so that they can be overridden by Makefile fragments.
-BOOT_CFLAGS= -g -O2
+BOOT_CFLAGS?= -g -O2
 BOOT_LDFLAGS=
 BOOT_ADAFLAGS= -gnatpg


And then you need to pass to configure and make the following env variables
CFLAGS_FOR_TARGET="-O0" CXXFLAGS_FOR_TARGET="-O0" BOOT_CFLAGS="-O0".
The first patch is already sent by Gustavo Romero from IBM to GCC patches list.

GCC10 needs further fixing, unfortunately.