[Bug debug/95080] New: [10/11 Regression] -fcompare-debug failure (length) with -Og -fcse-follow-jumps -fnon-call-exceptions

[zsojka at seznam dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95080

            Bug ID: 95080
           Summary: [10/11 Regression] -fcompare-debug failure (length)
                    with -Og -fcse-follow-jumps -fnon-call-exceptions
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: debug
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zsojka at seznam dot cz
                CC: aoliva at gcc dot gnu.org
  Target Milestone: ---
              Host: x86_64-pc-linux-gnu

Created attachment 48517
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48517&action=edit
reduced testcase

Compiler output:
$ x86_64-pc-linux-gnu-g++ -Og -fcse-follow-jumps -fnon-call-exceptions
-fcompare-debug testcase.C
x86_64-pc-linux-gnu-g++: error: testcase.C: '-fcompare-debug' failure (length)

$ diff -u testcase.gkd testcase.gk.gkd 
--- testcase.gkd        2020-05-12 13:14:06.626740964 +0200
+++ testcase.gk.gkd     2020-05-12 13:14:06.716740965 +0200
@@ -51,12 +51,10 @@
         (reg:DI 5 di [93]))# {*movdi_internal}
      (expr_list:REG_DEAD (reg:DI 5 di [93])
         (nil)))
-(insn # 0 0 4 (set (reg:QI 0 ax [orig:86 _11 ] [86])
-        (const_int 0 [0])) "testcase.C":8:14# {*movqi_internal}
+(insn # 0 0 4 (set (reg:QI 0 ax [orig:89 _14 ] [89])
+        (const_int 0 [0])) "testcase.C":15:14# {*movqi_internal}
      (expr_list:REG_EQUIV (const_int 0 [0])
-        (expr_list:REG_EH_REGION (const_int -1 [0xffffffffffffffff])
-            (nil))))
-(note # 0 0 NOTE_INSN_DELETED)
+        (nil)))
 (insn # 0 0 4 (set (reg:CCZ 17 flags)
         (compare:CCZ (reg:QI 0 ax [orig:89 _14 ] [89])
             (const_int 0 [0]))) "testcase.C":22:3# {*cmpqi_ccno_1}

$ x86_64-pc-linux-gnu-g++ -v
Using built-in specs.
COLLECT_GCC=/repo/gcc-trunk/binary-latest/bin/x86_64-pc-linux-gnu-g++
COLLECT_LTO_WRAPPER=/repo/gcc-trunk/binary-trunk-r11-314-20200512100527-g99b0c9ec47d-checking-yes-rtl-df-extra-amd64/bin/../libexec/gcc/x86_64-pc-linux-gnu/11.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /repo/gcc-trunk//configure --enable-languages=c,c++
--enable-valgrind-annotations --disable-nls --enable-checking=yes,rtl,df,extra
--with-cloog --with-ppl --with-isl --build=x86_64-pc-linux-gnu
--host=x86_64-pc-linux-gnu --target=x86_64-pc-linux-gnu
--with-ld=/usr/bin/x86_64-pc-linux-gnu-ld
--with-as=/usr/bin/x86_64-pc-linux-gnu-as --disable-libstdcxx-pch
--prefix=/repo/gcc-trunk//binary-trunk-r11-314-20200512100527-g99b0c9ec47d-checking-yes-rtl-df-extra-amd64
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 11.0.0 20200512 (experimental) (GCC)