From 0930c4e1872e12bfb6673f70c9b34ff6bb23b210 Mon Sep 17 00:00:00 2001 From: Georg-Johann Lay Date: Wed, 2 May 2012 17:05:04 +0000 Subject: Backport from 2011-07-08 4.6-branch r176055. PR target/46779 * config/avr/avr.c (avr_hard_regno_mode_ok): Rewrite. In particular, allow 8-bit values in r28 and r29. (avr_hard_regno_scratch_ok): Disallow any register that might be part of the frame pointer. (avr_hard_regno_rename_ok): Same. (avr_legitimate_address_p): Don't allow SUBREGs. git-svn-id: https://gcc.gnu.org/svn/gcc/branches/gcc-4_5-branch@187055 138bc75d-0d04-0410-961f-82ee72b054a4 --- gcc/ChangeLog | 12 ++++++++++ gcc/config/avr/avr.c | 62 ++++++++++++++++++++++++++++++++++++---------------- 2 files changed, 55 insertions(+), 19 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index f07f6ce8a82..a3c01a31b7d 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,15 @@ +2012-05-02 Georg-Johann Lay + + Backport from 2011-07-08 4.6-branch r176055. + + PR target/46779 + * config/avr/avr.c (avr_hard_regno_mode_ok): Rewrite. + In particular, allow 8-bit values in r28 and r29. + (avr_hard_regno_scratch_ok): Disallow any register that might be + part of the frame pointer. + (avr_hard_regno_rename_ok): Same. + (avr_legitimate_address_p): Don't allow SUBREGs. + 2012-04-30 Uros Bizjak Backport from mainline 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; } -- cgit v1.2.3