On 30.01.2012 11:38, Paolo Bonzini wrote:
On 01/29/2012 04:09 PM, Eric Botcazou wrote:
As discussed in Bugzilla, this is the patch implementing Paolo's
suggestion of killing REG_EQUAL/REG_EQUIV notes from df_kill_notes. The
code assumes there is at most one such note per insn.
That's wrong though and wreaks havoc during reload, e.g.:
(insn 169 60 62 4 (set (reg:TF 158)
(mem/c:TF (plus:SI (reg/f:SI 101 %sfp)
(const_int -16 [0xfffffffffffffff0])) [3 S16 A64]))
960513-1.c:13 97 {*movtf_insn_sp32}
(expr_list:REG_EQUIV (mem/c:TF (plus:SI (reg/f:SI 101 %sfp)
(const_int -16 [0xfffffffffffffff0])) [3 S16 A64])
(expr_list:REG_EQUAL (mult:TF (reg/v:TF 110 [ d ])
(reg:TF 154))
(nil))))
because the REG_EQUIV note disappears behind reload's back and it isn't
prepared for that. This is the cause of the following regression on SPARC:
FAIL: gcc.c-torture/execute/960513-1.c execution, -Os
As well as:
FAIL: gcc.c-torture/execute/stdarg-2.c execution, -O2
FAIL: gcc.c-torture/execute/stdarg-2.c execution, -O3 -fomit-frame-pointer
FAIL: gcc.c-torture/execute/stdarg-2.c execution, -O3 -g
FAIL: gcc.c-torture/execute/stdarg-2.c execution, -Os
FAIL: gcc.c-torture/execute/stdarg-2.c
execution, -O2 -flto -flto-partition=none
FAIL: gcc.c-torture/execute/stdarg-2.c execution, -O2 -flto
for the exact same reason.
Does this help?
That would fix the problem of multiple notes per insn (as we wanted to do
initially), but I didn't understand whether this is the real problem or the
problem is the reload not happy with disappearing notes. Also I can't
reproduce it with a cross to sparc64-linux -- when I put a breakpoint on
the code removing the notes, I find only similarly looking insn 148 which
gets removed from the df_analyze call at the start of IRA. Though I see
the fail from SPARC test results on the ML, so I guess I'm missing something...
Andrey
Paolo
