[Bug target/84113] [7/8 Regression] libgcc/unwind.inc:136:1: internal compiler error: in extract_insn, at recog.c:2311

[dougmencken at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84113

--- Comment #21 from Douglas Mencken  ---
Created attachment 43334
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=43334=edit
Reverting patch

I fully reverted that commit on top of gcc-7_3_0-release, and build succeeds

[Bug target/84113] [7/8 Regression] libgcc/unwind.inc:136:1: internal compiler error: in extract_insn, at recog.c:2311

[dougmencken at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84113

--- Comment #20 from Douglas Mencken  ---
$ git bisect good
good: [270b838d816f8a2c372eac0121adcdf570feccfa] Regenerate .pot files.
Bisecting: 90 revisions left to test after this (roughly 7 steps)
[6f2116bed6e87668a914dc27fff34c7a68576d4e]  PR libstdc++/77356  *
include/bits/regex_compiler.tcc(_M_insert_bracket_matcher,   
_M_expression_term): Modify to support dash literal.*
include/bits/regex_scanner.h: Add dash as a token type to makea
different from the mandated dash literal by escaping. *
include/bits/regex_scanner.tcc(_M_scan_in_bracket): Emit dash token in
bracket expression parsing.* testsuite/28_regex/regression.cc: Add new
testcases.
...
$ git bisect good
good: [6f2116bed6e87668a914dc27fff34c7a68576d4e]PR libstdc++/77356 
* include/bits/regex_compiler.tcc(_M_insert_bracket_matcher,   
_M_expression_term): Modify to support dash literal.*
include/bits/regex_scanner.h: Add dash as a token type to makea
different from the mandated dash literal by escaping. *
include/bits/regex_scanner.tcc(_M_scan_in_bracket): Emit dash token in bracket
expression parsing.* testsuite/28_regex/regression.cc: Add new testcases.
Bisecting: 45 revisions left to test after this (roughly 6 steps)
[304fb2e5e141baf6e9b6d4993389fc3d8acc7059] rs6000: Don't emit a use of LR in
returns and sibcalls
...
../.././libgcc/unwind.inc:136:1: internal compiler error: in extract_insn, at
recog.c:2310

This commit from Segher
https://gcc.gnu.org/ml/gcc-patches/2016-08/msg02040.html
looks very related, notably deleted instruction

“ The return_internal_ pattern can now be deleted since nothing uses it
anymore. ”

-(define_insn "*return_internal_"
-  [(simple_return)
-   (use (match_operand:P 0 "register_operand" "lc"))]
-  ""
-  "b%T0"
-  [(set_attr "type" "jmpreg")])

$ git bisect bad
bad: [304fb2e5e141baf6e9b6d4993389fc3d8acc7059] rs6000: Don't emit a use of LR
in returns and sibcalls
Bisecting: 21 revisions left to test after this (roughly 5 steps)
[17437807e9ee1d8ee95d957d31b98c3a6dadc220] selftest.h: mark failure functions
with ATTRIBUTE_NORETURN.
...
$ git bisect good
good: [17437807e9ee1d8ee95d957d31b98c3a6dadc220] selftest.h: mark failure
functions with ATTRIBUTE_NORETURN.
Bisecting: 10 revisions left to test after this (roughly 4 steps)
[77ce623298307d0d816cb8fc95728f9433a7e1e2]  PR debug/77389  *
g++.dg/debug/dwarf2/template-params-12f.C: Pass -gno-strict-dwarf in
dg-options.
$ git show
$ git bisect skip
Bisecting: 10 revisions left to test after this (roughly 4 steps)
[850c20095027d73b4cff0a1bb43dc33192d8c30c] rich_location: add convenience
overloads for adding fix-it hints
...
$ git bisect good
good: [850c20095027d73b4cff0a1bb43dc33192d8c30c] rich_location: add convenience
overloads for adding fix-it hints
Bisecting: 1 revision left to test after this (roughly 1 step)
[53187361667797547265d910db5733744288b63f] 2016-08-30  Fritz Reese 

$ git show
$ git bisect skip
Bisecting: 1 revision left to test after this (roughly 1 step)
[9a6075867d2af9ed1feaa645a81a5f80aca49150] [PATCH][Aarch64][gcc] Fix vld2/3/4
on big endian systems
...
$ git bisect good
304fb2e5e141baf6e9b6d4993389fc3d8acc7059 is the first bad commit

Yep, it is

[Bug target/84113] [7/8 Regression] libgcc/unwind.inc:136:1: internal compiler error: in extract_insn, at recog.c:2311

[dougmencken at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84113

--- Comment #19 from Douglas Mencken  ---
I got repo from git://gcc.gnu.org/git/gcc.git and begun to bisect it to find
the cause of regression

"good" here means reaching build of libstdc++-v3 after than problem libgcc

$ git bisect start
$ git bisect good gcc-6_4_0-release
good: [45dd06cef49fe00a7839d7dff312b09e88910a51] Update ChangeLog and version
files for release
$ git bisect bad gcc-7_1_0-release
bad: [f9105a38249fb57f7778acf3008025f2dcac2b1f] Update ChangeLog and version
files for release
Bisecting: a merge base must be tested
...
$ git bisect good
good: [a050099a416f013bda35832b878d9a57b0cbb231]PR c++/70594*
constexpr.c (constexpr_call_table): Preserve in GC.   (struct fundef_copy,
struct fundef_copies_table_t): Delete. (fundef_copies_table):
Preserve in GC. Change to pointer to tree->tree hash.   
(maybe_initialize_fundef_copies_table): Adjust. (get_fundef_copy):
Return a TREE_LIST.  Use non-inserting search.   (save_fundef_copy): Adjust
for a TREE_LIST. (cxx_eval_call_expression): Adjust for a fundef_copy
TREE_LIST. (fini_constexpr): New.  * cp-tree.h (fini_constexpr):
Declare.  * decl2.c (c_parse_final_cleanups): Call fini_constexpr.
Bisecting: 3873 revisions left to test after this (roughly 12 steps)
[20f2fdd71e4f2acb8e4ade02c9d031c1633ec8dd] Daily bump.
...
Makefile:1642: ../.././gcc/java/Make-lang.in: No such file or directory
make[3]: *** No rule to make target `../.././gcc/java/Make-lang.in'.  Stop.
make[2]: *** [all-stage1-gcc] Error 2
...
$ git bisect skip
skip: [20f2fdd71e4f2acb8e4ade02c9d031c1633ec8dd] Daily bump.
Bisecting: 3873 revisions left to test after this (roughly 12 steps)
[4e91a07b9010003cb22c22c20c6aa6417a57333b] PR tree-optimization/71831 -
__builtin_object_size poor results with no  optimization
...
../.././libgcc/unwind.inc:136:1: internal compiler error: in extract_insn, at
recog.c:2310
...
$ git bisect bad
bad: [4e91a07b9010003cb22c22c20c6aa6417a57333b] PR tree-optimization/71831 -
__builtin_object_size poor results with no optimization
Bisecting: 1461 revisions left to test after this (roughly 11 steps)
[035778dec3d7f2895fec1259f912498f77be569a] /cp 2016-06-14  Paolo Carlini 

...
$ git bisect good
good: [035778dec3d7f2895fec1259f912498f77be569a] /cp 2016-06-14  Paolo Carlini 

Bisecting: 730 revisions left to test after this (roughly 10 steps)
[1660595b07f5f618405c23a11af6160eef5b23e2] Fix tests for targets with
sizeof(int) != 32.
...
$ git bisect good
good: [1660595b07f5f618405c23a11af6160eef5b23e2] Fix tests for targets with
sizeof(int) != 32.
Bisecting: 364 revisions left to test after this (roughly 9 steps)
[081a6ff0f79d63a83a561d8178baabcad5c7ff08] [RS6000] e500 part of pr71680
...
$ git bisect good
good: [081a6ff0f79d63a83a561d8178baabcad5c7ff08] [RS6000] e500 part of pr71680
Bisecting: 181 revisions left to test after this (roughly 8 steps)
[270b838d816f8a2c372eac0121adcdf570feccfa] Regenerate .pot files.
...

[Bug target/84113] [7/8 Regression] libgcc/unwind.inc:136:1: internal compiler error: in extract_insn, at recog.c:2311

[dougmencken at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84113

--- Comment #18 from Douglas Mencken  ---
(In reply to Douglas Mencken from comment #17)
> diff of libgcc/unwind-dw2.c between 6.4 and 7.1
> 
Reverting this file doesn’t help