https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101559
Bug ID: 101559
Summary: RISCV -- incorrect label address when using -O2
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: joel.porquet at gmail dot com
Target Milestone: ---
The GNU construct `&&label` supposedly allows the programmer to get the address
corresponding to a label. When compiling for RISCV, the correct address is
computed when compiling with -O0 but not with -O2.
Here is an example code where a label's address is properly computed:
https://godbolt.org/z/qnEafeY6f. As you can see, the address corresponding to
label `.L2` is properly retrieved using `lui` followed by `addi` and placed
into register `a5`.
Now, when the same code is compiled with `-O2`, the address is not properly
computed: https://godbolt.org/z/n8zbbTnhb. As you can see, the label `.L2` is
now placed at the very beginning of the function and points onto the function's
first instruction. As a result, the computed address will not correspond to
where the label was placed in the original code.
Is that a bug, or am I missing something? Thanks!
