[Bug lto/78353] New: -flto omits some -Wl flags

[nico at linaro dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78353

            Bug ID: 78353
           Summary: -flto omits some -Wl flags
           Product: gcc
           Version: 6.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: lto
          Assignee: unassigned at gcc dot gnu.org
          Reporter: nico at linaro dot org
  Target Milestone: ---
              Host: ARM
            Target: ARM
             Build: ARM

Given the following test code:

int main(int x)
{
        asm("teq %0, #0; addne %0, %0, #1" : "=r" (x));
        return x;
}

$ gcc -march=armv7-a -mthumb -O2 -o test test.c
/tmp/cc1cDOSv.s: Assembler messages:
/tmp/cc1cDOSv.s:28: Error: thumb conditional instruction should be in IT block
-- `addne r0,r0,#1'

That was expected to fail.

Now adding -Wa,-mimplicit-it=always to it:

$ gcc -march=armv7-a -mthumb -O2 -Wa,-mimplicit-it=always -o test test.c

Compilation completes. That was expected to work.

Finally, adding -flto to that:

$ gcc -march=armv7-a -mthumb -O2 -flto -Wa,-mimplicit-it=always -o test test.c
/tmp/ccjAV98m.s: Assembler messages:
/tmp/ccjAV98m.s:27: Error: thumb conditional instruction should be in IT block
-- `addne r0,r0,#1'
lto-wrapper: fatal error: gcc returned 1 exit status
compilation terminated.
/opt/gcc-6.2.1/bin/../lib/gcc/arm-linux-gnueabihf/6.2.1/../../../../arm-linux-gnueabihf/bin/ld:
error: lto-wrapper failed
collect2: error: ld returned 1 exit status

Certainly that wasn't supposed to fail.