On 9/20/20 5:08 PM, Marek Polacek via Gcc-patches wrote:
We crash here because since r11-3302 the C FE uses codes like SWITCH_STMT in the else branches in the attached test, and inchash::add_expr in do_warn_duplicated_branches doesn't handle these front-end codes. In the C++ FE this works because by the time we get to do_warn_duplicated_branches we've already cp_genericize'd the SWITCH_STMT tree into a SWITCH_EXPR.The fix is to call do_warn_duplicated_branches_r only after loops and other structured control constructs have been lowered. Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk? gcc/c-family/ChangeLog: PR c/97125 * c-gimplify.c (c_genericize): Only call do_warn_duplicated_branches_r after loops and other structured control constructs have been lowered. gcc/testsuite/ChangeLog: PR c/97125 * c-c++-common/Wduplicated-branches-15.c: New test.
As I noted in the issue, this was my bad, and the fix looks good to me (although I have no authority to approve it).
The same problem was independently reported as PR c/97157. -Sandra
