Testing the patch kit on i686 showed numerous failures of this
assertion in set_mem_attributes_minus_bitpos in emit-rtl.c:
1821 gcc_assert (!defattrs->offset_known_p);
when expanding "main" in the rtl.exp test files, after parsing
an __RTL-tagged function.
Root cause is various assignments within the RTL parser of the
form:
1222 MEM_OFFSET (x) = atoi (name.string);
where a MEM_* macro appears on the left-hand side of an assignment.
These macros are defined as a field lookup on the result of a call
to get_mem_attrs, e.g.:
#define MEM_OFFSET(RTX) (get_mem_attrs (RTX)->offset)
get_mem_attrs can return the struct mem_attrs * of an rtx, but if
it isn't set, it returns:
mode_mem_attrs[(int) GET_MODE (x)];
which is this field within struct GTY(()) target_rtl:
/* The default memory attributes for each mode. */
struct mem_attrs *x_mode_mem_attrs[(int) MAX_MACHINE_MODE];
These assignments in the parser were erroneously writing to these
default per-mode values, rather than assigning to a unique-per-rtx
instance of struct mem_attrs.
The fix is to call the appropriate set_mem_ functions in the
parser, e.g. set_mem_offset; the patch below is intended as a tweak
to patch 8a of the kit, and would be merged with it before committing.
The patch also adds extra test coverage for MEM parsing. This extends
the target-independent selftests, and so would go into patch 8b.
Tested for targets x86_64-pc-linux-gnu, i686-pc-linux-gnu,
and aarch64-linux-gnu, and on powerpc-ibm-aix7.1.3.0.
OK as adjustments to patches 8a and 8b?
For patch 8a:
gcc/ChangeLog:
* read-rtl-function.c
(function_reader::handle_any_trailing_information): Replace writes
through macros MEM_ALIAS_SET, MEM_OFFSET, MEM_SIZE, MEM_ALIGN,
and MEM_ADDR_SPACE with calls to set_mem_ functions. Add missing
call to unread_char when handling "A" for alignment.
For patch 8b:
gcc/ChangeLog:
* read-rtl-function.c (selftest::test_loading_mem): New function.
(selftest::read_rtl_function_c_tests): Call it.
gcc/testsuite/ChangeLog:
* selftests/mem.rtl: New file.