[Bug lto/77716] New: [7 regression] test case gcc.dg/debug/dwarf2/const-2.c fails starting with r240228

[seurer at linux dot vnet.ibm.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77716

            Bug ID: 77716
           Summary: [7 regression] test case gcc.dg/debug/dwarf2/const-2.c
                    fails starting with r240228
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: lto
          Assignee: unassigned at gcc dot gnu.org
          Reporter: seurer at linux dot vnet.ibm.com
  Target Milestone: ---

This fails on powerpc64 both BE and LE.

Executing on host: /home/seurer/gcc/build/gcc-test2/gcc/xgcc
-B/home/seurer/gcc/build/gcc-test2/gcc/
/home/seurer/gcc/gcc-test2/gcc/testsuite/gcc.dg/debug/dwarf2/const-2.c 
-fno-diagnostics-show-caret -fdiagnostics-color=never  -O -gdwarf -dA -maltivec
-ffat-lto-objects -S   -o const-2.s    (timeout = 300)
spawn /home/seurer/gcc/build/gcc-test2/gcc/xgcc
-B/home/seurer/gcc/build/gcc-test2/gcc/
/home/seurer/gcc/gcc-test2/gcc/testsuite/gcc.dg/debug/dwarf2/const-2.c
-fno-diagnostics-show-caret -fdiagnostics-color=never -O -gdwarf -dA -maltivec
-ffat-lto-objects -S -o const-2.s
PASS: gcc.dg/debug/dwarf2/const-2.c (test for excess errors)
FAIL: gcc.dg/debug/dwarf2/const-2.c scan-assembler DW_AT_const_value

16c16
<       .4byte  .LASF0   # DW_AT_producer: "GNU C11 7.0.0 20160919
(experimental) [trunk revision 240227] -Asystem=linux -Asystem=unix
-Asystem=posix -maltivec -gdwarf -O -ffat-lto-objects"
---
> 	.4byte	.LASF0	 # DW_AT_producer: "GNU C11 7.0.0 20160919 (experimental) [trunk revision 240228] -Asystem=linux -Asystem=unix -Asystem=posix -maltivec -gdwarf -O -ffat-lto-objects"
41,45d40
<       .byte   0x10     # DW_AT_const_value
<       .4byte  0x4d6e6b28       # fp or vector constant word 0
<       .4byte  0        # fp or vector constant word 1
<       .4byte  0        # fp or vector constant word 2
<       .4byte  0        # fp or vector constant word 3
115,116d109
<       .uleb128 0x1c    # (DW_AT_const_value)
<       .uleb128 0xa     # (DW_FORM_block1)

This block is missing in the assembler output after the revision.

Hmmm.  Perhaps it is related to this issue:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77692