I find that when compiling some files, lra goes into an infinite loop
reloading constant
addresses. This patch allows them to just be recognized as matching addresses
immediately, which also saves a bit of space for a few other files.
Bootstrapped and regression tested on x86_64-pc-linux-gnu.
gcc/
* lra-constraints.c: New arguments mem_mode and as. Changed caller.
If equivalence search has yielded a constant that is valid as an
address, use it.
diff --git a/gcc/lra-constraints.c b/gcc/lra-constraints.c
index a766f1fd7e8..8451da58164 100644
--- a/gcc/lra-constraints.c
+++ b/gcc/lra-constraints.c
@@ -1454,10 +1454,14 @@ static int curr_swapped;
the RTL was changed.
if CHECK_ONLY_P is true, check that the *LOC is a correct address
- register. Return false if the address register is correct. */
+ register. Return false if the address register is correct.
+
+ if MEM_MODE is not VOIDmode, then *LOC is the entire address for a
+ memory access of MODE in address space AS, and *LOC may be replaced
+ with a constant if that is a valid address. */
static bool
process_addr_reg (rtx *loc, bool check_only_p, rtx_insn **before, rtx_insn
**after,
- enum reg_class cl)
+ enum reg_class cl, machine_mode mem_mode, addr_space_t as)
{
int regno;
enum reg_class rclass, new_class;
@@ -1502,6 +1506,13 @@ process_addr_reg (rtx *loc, bool check_only_p, rtx_insn
**before, rtx_insn **aft
if (! check_only_p
&& (*loc = get_equiv_with_elimination (reg, curr_insn)) != reg)
{
+ /* If the elimination has yielded a constant that is fine as an
+ address, don't try to reload that. */
+ if (CONSTANT_P (*loc) && mem_mode != VOIDmode
+ && strict_memory_address_addr_space_p
+ (mem_mode, *loc, as))
+ return true;
+
if (lra_dump_file != NULL)
{
fprintf (lra_dump_file,
@@ -3523,7 +3534,12 @@ process_address_1 (int nop, bool check_only_p,
REGNO (*ad.base_term)) != NULL_RTX)
? after : NULL),
base_reg_class (ad.mode, ad.as, ad.base_outer_code,
- get_index_code (&ad)))))
+ get_index_code (&ad)),
+ ((MEM_P (mem) && &XEXP (mem, 0) == ad.base_term)
+ || (SUBREG_P (op) && MEM_P (SUBREG_REG (op))
+ && &XEXP (SUBREG_REG (op), 0) == ad.base_term)
+ ? ad.mode : VOIDmode),
+ ad.as)))
{
change_p = true;
if (ad.base_term2 != NULL)
@@ -3531,7 +3547,7 @@ process_address_1 (int nop, bool check_only_p,
}
if (ad.index_term != NULL
&& process_addr_reg (ad.index_term, check_only_p,
- before, NULL, INDEX_REG_CLASS))
+ before, NULL, INDEX_REG_CLASS, VOIDmode, ad.as))
change_p = true;
/* Target hooks sometimes don't treat extra-constraint addresses as
