I have a port that has:
(insn 47 46 48 18 (parallel [
(unspec_volatile:DI [
(const_int 128 [0x80])
(const_int 6 [0x6])
] UNSPECV_SPECIAL_OP)
(set (mem/v:BLK (scratch:DI) [0 A8])
(unspec:BLK [
(mem/v:BLK (scratch:DI) [0 A8])
] UNSPEC_MEMORY_BARRIER))
The UNSPEC_MEMORY_BARRIER is the usual memory barrier, and the other unspec is
a random complex instruction that the optimizer will never have a clue about.
I caught lra trying to reload the scratch address into a register and then
aborting later as it isn’t a use, a clobber or an asm_input. The code that
asserts this is:
/* It is a special insn like USE or CLOBBER. We should
recognize any regular insn otherwise LRA can do nothing
with this insn. */
gcc_assert (GET_CODE (PATTERN (insn)) == USE
|| GET_CODE (PATTERN (insn)) == CLOBBER
|| GET_CODE (PATTERN (insn)) == ASM_INPUT);
in lra.c I notice that if I put in the below, I can get lra to not do the
reload. I get the feeling that I’m missing something from my port someplace
else that would have prevented lra from doing this, as we have a ton of ports
that have this form of memory barrier. avr nopv is one such instance. [
checking ] Oh, avr is one such port, but, it doesn’t use lra. :-( Hum…
So, I guess the question is, is this an lra bug, or a port bug? When I use the
avr patterns for nopv on an lra port, the pattern then doesn’t work.
diff --git a/gcc/lra-constraints.c b/gcc/lra-constraints.c
index 382281c..c82aa3f 100644
--- a/gcc/lra-constraints.c
+++ b/gcc/lra-constraints.c
@@ -2855,6 +2855,7 @@ process_address_1 (int nop, bool check_only_p,
if (! check_only_p)
change_p = equiv_address_substitution (&ad);
if (ad.base_term != NULL
+ && GET_CODE (*ad.base_term) != SCRATCH
&& (process_addr_reg
(ad.base_term, check_only_p, before,
(ad.autoinc_p
@@ -2898,7 +2899,9 @@ process_address_1 (int nop, bool check_only_p,
All these cases involve a non-autoinc address, so there is no
point revalidating other types. */
- if (ad.autoinc_p || valid_address_p (&ad))
+ if (ad.autoinc_p
+ || (ad.base_term && GET_CODE (*ad.base_term) == SCRATCH)
+ || valid_address_p (&ad))
return change_p;
/* Any index existed before LRA started, so we can assume that the
