Here is one more patch concerning
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61325
The following patch prevents complex address transformation just by
checking a change in address validity of subreg memory substitution.
The patch was bootstrapped and tested on x86-64.
Committed as rev. 211716 to gcc-4.9-branch and as rev. 211715 to the trunk.
2014-06-16 Vladimir Makarov <vmaka...@redhat.com>
PR rtl-optimization/61325
* lra-constraints.c (valid_address_p): Add forward declaration.
(simplify_operand_subreg): Check address validity before and after
alter_reg of memory subreg.
Index: lra-constraints.c
===================================================================
--- lra-constraints.c (revision 211654)
+++ lra-constraints.c (working copy)
@@ -1231,6 +1231,8 @@
}
}
+static int valid_address_p (enum machine_mode mode, rtx addr, addr_space_t as);
+
/* Make reloads for subreg in operand NOP with internal subreg mode
REG_MODE, add new reloads for further processing. Return true if
any reload was generated. */
@@ -1261,12 +1263,28 @@
equivalences in function lra_constraints) and because for spilled
pseudos we allocate stack memory enough for the biggest
corresponding paradoxical subreg. */
- if ((MEM_P (reg)
- && (! SLOW_UNALIGNED_ACCESS (mode, MEM_ALIGN (reg))
- || MEM_ALIGN (reg) >= GET_MODE_ALIGNMENT (mode)))
- || (REG_P (reg) && REGNO (reg) < FIRST_PSEUDO_REGISTER))
+ if (MEM_P (reg)
+ && (! SLOW_UNALIGNED_ACCESS (mode, MEM_ALIGN (reg))
+ || MEM_ALIGN (reg) >= GET_MODE_ALIGNMENT (mode)))
{
+ rtx subst, old = *curr_id->operand_loc[nop];
+
alter_subreg (curr_id->operand_loc[nop], false);
+ subst = *curr_id->operand_loc[nop];
+ lra_assert (MEM_P (subst));
+ if (! valid_address_p (GET_MODE (reg), XEXP (reg, 0),
+ MEM_ADDR_SPACE (reg))
+ || valid_address_p (GET_MODE (subst), XEXP (subst, 0),
+ MEM_ADDR_SPACE (subst)))
+ return true;
+ /* If the address was valid and became invalid, prefer to reload
+ the memory. Typical case is when the index scale should
+ correspond the memory. */
+ *curr_id->operand_loc[nop] = old;
+ }
+ else if (REG_P (reg) && REGNO (reg) < FIRST_PSEUDO_REGISTER)
+ {
+ alter_subreg (curr_id->operand_loc[nop], false);
return true;
}
/* Put constant into memory when we have mixed modes. It generates
