[testsuite] Test case for PR rtl-optimization/60473

Uros Bizjak ubizjak@gmail.com
Mon Aug 3 10:01:41 GMT 2020


>> Since GCC 4.9 (including current mainline), it generates optimal
>>
>> code with no mov instructions, matching what used to be generated
>>
>> in GCC 4.1.
>>
>>
>>
>> foo:    rdtsc
>>
>>         sal     rdx, 32
>>
>>         or      rax, rdx
>>
>>         ret
>>
>>
>>
>> This test case, which has been tested on x86_64-pc-linux-gnu,
>>
>> simply checks that we don't regress again in future.
>>
>> Ok for mainline?
>
> I think you need to restrict this to lp64, at least it fails for me with -m32.
> It also passes with -mx32 but not sure how the perfect target selector
> would look like.

/* { dg-do compile { target { ! ia32 } } } */

should do the trick.

> Otherwise looks OK.

+/* { dg-final { scan-assembler-not "mov" } } */

This test is maybe too fragile, some targets generate frame setup
instructions, e.g.:

        movl    %esp, %ebp

that will trigger the FAIL. If there are false positives, we can add a
target selector for *-*-linux to scan-assembler-not.

Uros.


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