[Bug rtl-optimization/66556] New: Wrong code-generation for armv7-a big-endian at -Os

[renlin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66556

            Bug ID: 66556
           Summary: Wrong code-generation for armv7-a big-endian at -Os
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: renlin at gcc dot gnu.org
  Target Milestone: ---

Created attachment 35789
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35789&action=edit
test case

The test case is attached.

toolchain built from latest trunk code and branch 5 produce wrong
code-generation with the following command line option.

arm-none-eabi-gcc -march=armv7-a -mbig-endian -Os test.c -o test.out

The correct output should be:
checksum = ff

However, the result is:
checksum = 7

The testcase is correctly compiled at -O1, which gives the right execution
result. The test case works fine for little-endian at any optimization level.