[Bug debug/100852] New: [11/12 Regression] -fcompare-debug failure (length) with -Og -fif-conversion -fno-tree-ccp -fno-tree-copy-prop

[zsojka at seznam dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100852

            Bug ID: 100852
           Summary: [11/12 Regression] -fcompare-debug failure (length)
                    with -Og -fif-conversion -fno-tree-ccp
                    -fno-tree-copy-prop
           Product: gcc
           Version: 12.0
            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 50902
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50902&action=edit
reduced testcase

Compiler output:
$ x86_64-pc-linux-gnu-gcc -Og -fif-conversion -fno-tree-ccp -fno-tree-copy-prop
-fcompare-debug testcase.C -save-temps
x86_64-pc-linux-gnu-gcc: error: testcase.C: '-fcompare-debug' failure (length)

$ diff -u *gkd
--- a-testcase.C.gkd    2021-06-01 12:41:23.194487854 +0200
+++ a-testcase.gk.C.gkd 2021-06-01 12:41:23.294487994 +0200
@@ -25,10 +25,11 @@
 (note # 0 0 NOTE_INSN_DELETED)
 (note # 0 0 NOTE_INSN_DELETED)
 (note # 0 0 NOTE_INSN_DELETED)
+(note # 0 0 NOTE_INSN_DELETED)
 (insn # 0 0 2 (set (reg:SI 4 si)
         (const_int 0 [0])) "testcase.C":17:10# {*movsi_internal}
      (nil))
-(insn # 0 0 2 (set (reg:DI 5 di [92])
+(insn # 0 0 2 (set (reg:DI 5 di [93])
         (plus:DI (reg/f:DI 7 sp)
             (const_int 15 [0xf]))) "testcase.C":17:10# {*leadi}
      (nil))

$ x86_64-pc-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=/repo/gcc-trunk/binary-latest-amd64/bin/x86_64-pc-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/repo/gcc-trunk/binary-trunk-r12-1138-20210601095814-g28daadc9809-checking-yes-rtl-df-extra-amd64/bin/../libexec/gcc/x86_64-pc-linux-gnu/12.0.0/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-r12-1138-20210601095814-g28daadc9809-checking-yes-rtl-df-extra-amd64
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 12.0.0 20210601 (experimental) (GCC)