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Diffstat (limited to 'gcc/config/avr/avr.c')
-rw-r--r--gcc/config/avr/avr.c62
1 files changed, 43 insertions, 19 deletions
diff --git a/gcc/config/avr/avr.c b/gcc/config/avr/avr.c
index 639c770e8a8..c8655bd517d 100644
--- a/gcc/config/avr/avr.c
+++ b/gcc/config/avr/avr.c
@@ -1043,8 +1043,7 @@ avr_legitimate_address_p (enum machine_mode mode, rtx x, bool strict)
true_regnum (XEXP (x, 0)));
debug_rtx (x);
}
- if (!strict && GET_CODE (x) == SUBREG)
- x = SUBREG_REG (x);
+
if (REG_P (x) && (strict ? REG_OK_FOR_BASE_STRICT_P (x)
: REG_OK_FOR_BASE_NOSTRICT_P (x)))
r = POINTER_REGS;
@@ -5934,26 +5933,30 @@ jump_over_one_insn_p (rtx insn, rtx dest)
int
avr_hard_regno_mode_ok (int regno, enum machine_mode mode)
{
- /* Disallow QImode in stack pointer regs. */
- if ((regno == REG_SP || regno == (REG_SP + 1)) && mode == QImode)
- return 0;
-
- /* The only thing that can go into registers r28:r29 is a Pmode. */
- if (regno == REG_Y && mode == Pmode)
- return 1;
-
- /* Otherwise disallow all regno/mode combinations that span r28:r29. */
- if (regno <= (REG_Y + 1) && (regno + GET_MODE_SIZE (mode)) >= (REG_Y + 1))
- return 0;
-
- if (mode == QImode)
+ /* NOTE: 8-bit values must not be disallowed for R28 or R29.
+ Disallowing QI et al. in these regs might lead to code like
+ (set (subreg:QI (reg:HI 28) n) ...)
+ which will result in wrong code because reload does not
+ handle SUBREGs of hard regsisters like this, see PR46779.
+ This could be fixed in reload. However, it appears
+ that fixing reload is not wanted by reload people. */
+
+ /* Any GENERAL_REGS register can hold 8-bit values. */
+
+ if (GET_MODE_SIZE (mode) == 1)
return 1;
- /* Modes larger than QImode occupy consecutive registers. */
- if (regno + GET_MODE_SIZE (mode) > FIRST_PSEUDO_REGISTER)
+ /* FIXME: Ideally, the following test is not needed.
+ However, it turned out that it can reduce the number
+ of spill fails. AVR and it's poor endowment with
+ address registers is extreme stress test for reload. */
+
+ if (GET_MODE_SIZE (mode) >= 4
+ && regno >= REG_X)
return 0;
- /* All modes larger than QImode should start in an even register. */
+ /* All modes larger than 8 bits should start in an even register. */
+
return !(regno & 1);
}
@@ -6080,13 +6083,23 @@ avr_hard_regno_scratch_ok (unsigned int regno)
&& !df_regs_ever_live_p (regno))
return false;
+ /* Don't allow hard registers that might be part of the frame pointer.
+ Some places in the compiler just test for [HARD_]FRAME_POINTER_REGNUM
+ and don't care for a frame pointer that spans more than one register. */
+
+ if ((!reload_completed || frame_pointer_needed)
+ && (regno == REG_Y || regno == REG_Y + 1))
+ {
+ return false;
+ }
+
return true;
}
/* Return nonzero if register OLD_REG can be renamed to register NEW_REG. */
int
-avr_hard_regno_rename_ok (unsigned int old_reg ATTRIBUTE_UNUSED,
+avr_hard_regno_rename_ok (unsigned int old_reg,
unsigned int new_reg)
{
/* Interrupt functions can only use registers that have already been
@@ -6097,6 +6110,17 @@ avr_hard_regno_rename_ok (unsigned int old_reg ATTRIBUTE_UNUSED,
&& !df_regs_ever_live_p (new_reg))
return 0;
+ /* Don't allow hard registers that might be part of the frame pointer.
+ Some places in the compiler just test for [HARD_]FRAME_POINTER_REGNUM
+ and don't care for a frame pointer that spans more than one register. */
+
+ if ((!reload_completed || frame_pointer_needed)
+ && (old_reg == REG_Y || old_reg == REG_Y + 1
+ || new_reg == REG_Y || new_reg == REG_Y + 1))
+ {
+ return 0;
+ }
+
return 1;
}