https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106188
Bug ID: 106188
Summary: [11.3 Regression] [coroutines] Incorrect frame layout
after transforming conditional statement without
top-level bind expression
Product: gcc
Version: 11.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: gcc-bugzilla at decltype dot org
Target Milestone: ---
Created attachment 53257
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53257&action=edit
Minimal test case
During `morph_fn_to_coro`, `await_statement_walker` rewrites IF and SWITCH
statements by breaking the condition out into a local variable. The new
variable is inserted at the beginning of the containing bind expression.
If the original function lacked a top-level bind expression, this pushes the
resume function pointer and all following fixed-layout frame members away from
their intended placement.
Expected frame layout:
_Coro_resume_fn
_Coro_destroy_fn
_Coro_promise
_Coro_self_handle
params
_Coro_resume_index
_Coro_frame_needs_free
_Coro_initial_await_resume_called
locals (ifcd/swch)
Actual frame layout (since 11.3.0):
locals (ifcd/swch) <- out of place
_Coro_resume_fn
_Coro_destroy_fn
_Coro_promise
_Coro_self_handle
params
_Coro_resume_index
_Coro_frame_needs_free
_Coro_initial_await_resume_called
The attached program triggers this error and crashes. Uncommenting the unused
local variable resolves the crash.
