On 8/22/24 2:46 AM, Richard Sandiford wrote:
This patch fixes gcc.c-torture/compile/opout.c for m68k with LRA
enabled. The test has:
...
z (a, b)
{
return (int) &a + (int) &b + (int) x + (int) z;
}
so it adds the address of two incoming arguments. This ends up
being treated as an LEA in which the "index" is the incoming
argument pointer, which the LEA multiplies by 2. The incoming
argument pointer is then eliminated, leading to:
(plus:SI (plus:SI (ashift:SI (plus:SI (reg/f:SI 24 %argptr)
(const_int -4 [0xfffffffffffffffc]))
(const_int 1 [0x1]))
(reg/f:SI 41 [ _6 ]))
(const_int 20 [0x14]))
In the address_info scheme, the innermost plus has to be treated
as the index "term", since that's the thing that's subject to
index_reg_class.
Tested on aarch64-linux-gnu, powerpc64le-linux-gnu, and
x86_64-linux-gnu. Also tested by building at least one target
per CPU directory and checking that there were no asm changes or
new ICEs when compiling gcc.c-torture, gcc.dg, and g++.dg at -Os.
OK to install?
Richard
gcc/
PR middle-end/116413
* rtl.h (address_info): Update commentary.
* rtlanal.cc (valid_base_or_index_term_p): New function, split
out from...
(get_base_term, get_index_term): ...here. Handle elimination PLUSes.
Ugh. What a mess. But what's one small delta on top of this house of
cards? :-)
OK for the trunk.
Jeff
