[Bug target/18002] New: [3.4/4.0 Regression] 'while' loop performace regression on avr target

[Bug target/18002] New: [3.4/4.0 Regression] 'while' loop performace regression on avr target

[berndtrog at yahoo dot com]

Hello,
when I compile(avr-gcc -c -Os -mmcu=atmega8 test.c) this code:

int main (void)
{
 while (((*(volatile unsigned char *)((0x0B) + 0x20)) & (1<<5)) == 0) {
  ;
 }

 return (0);
}

with gcc 3.3.1 I get this asm loop:

   8:   5d 9b           sbis    0x0b, 5 ; 11
   a:   fe cf           rjmp    .-4             ; 0x8


with gcc 3.4.2 or 4.0.0 I get this:

   8:   41 e0           ldi     r20, 0x01       ; 1
   a:   50 e0           ldi     r21, 0x00       ; 0 
   c:   8b b1           in      r24, 0x0b       ; 11
   e:   99 27           eor     r25, r25
  10:   25 e0           ldi     r18, 0x05       ; 5
  12:   96 95           lsr     r25
  14:   87 95           ror     r24
  16:   2a 95           dec     r18
  18:   e1 f7           brne    .-8             ; 0x12
  1a:   84 27           eor     r24, r20
  1c:   95 27           eor     r25, r21
  1e:   9c 01           movw    r18, r24
  20:   21 70           andi    r18, 0x01       ; 1
  22:   30 70           andi    r19, 0x00       ; 0
  24:   80 fd           sbrc    r24, 0
  26:   f2 cf           rjmp    .-28            ; 0xc

-- 
           Summary:  [3.4/4.0 Regression] 'while' loop performace regression
                    on avr target
           Product: gcc
           Version: 3.4.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: target
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: berndtrog at yahoo dot com
                CC: gcc-bugs at gcc dot gnu dot org
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: avr-elf


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18002

[Bug middle-end/18002] [3.4/4.0 Regression] 'while' loop performace regression on avr target

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-10-14 20:04 -------
Actually this is also a regression on PPC:
3.3:
_main:
        li r2,43
L2:
        lbz r3,0(r2)
        andi. r9,r3,32
        beq+ cr0,L2
        li r3,0
        blr

4.0.0:
L3:
        lbz r0,0(r2)
        xori r0,r0,32
        andi. r9,r0,32
        bne+ cr0,L3
        li r3,0
        blr

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
          Component|target                      |middle-end
     Ever Confirmed|                            |1
           Keywords|                            |missed-optimization
   Last reconfirmed|0000-00-00 00:00:00         |2004-10-14 20:04:00
               date|                            |
            Summary| [3.4/4.0 Regression]       |[3.4/4.0 Regression] 'while'
                   |'while' loop performace     |loop performace regression
                   |regression on avr target    |on avr target
   Target Milestone|---                         |3.4.3


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18002

[Bug middle-end/18002] [3.4/4.0 Regression] 'while' loop performace regression on avr target

[dje at gcc dot gnu dot org]

------- Additional Comments From dje at gcc dot gnu dot org  2004-10-15 20:16 -------
Proposed patch:
http://gcc.gnu.org/ml/gcc-patches/2004-10/msg01299.html

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18002

[Bug rtl-optimization/18002] [3.4/4.0 Regression] 'while' loop performace regression on avr target

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2004-10-18 18:47 -------
Subject: Bug 18002

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	dje@gcc.gnu.org	2004-10-18 18:47:40

Modified files:
	gcc            : ChangeLog 

Log message:
	Note PR rtl-optimization/18002.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&r1=2.5931&r2=2.5932



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18002

[Bug target/18002] [4.0/3.4 Regression] 'while' loop performace regression on avr target

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-10-25 21:42 -------
Oh, it looks like the powerpc bug was different from the avr one and for the avr bug it looks like a 
target problem and nothing else, the rtl looks small.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|rtl-optimization            |target
            Summary|[3.4 Regression] 'while'    |[4.0/3.4 Regression] 'while'
                   |loop performace regression  |loop performace regression
                   |on avr target               |on avr target


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18002

[Bug target/18002] [4.0/3.4 Regression] 'while' loop performace regression on avr target

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |minor
   GCC host triplet|i686-pc-linux-gnu           |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18002

[Bug target/18002] [4.0/3.4 Regression] 'while' loop performace regression on avr target

[mmitchel at gcc dot gnu dot org]

------- Additional Comments From mmitchel at gcc dot gnu dot org  2004-11-01 00:44 -------
Postponed until GCC 3.4.4.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|3.4.3                       |3.4.4


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18002

[Bug target/18002] [3.4/4.0 Regression] 'while' loop performace regression on avr target

[giovannibajo at libero dot it]

------- Additional Comments From giovannibajo at libero dot it  2004-12-09 12:50 -------
Proposed patch:
http://gcc.gnu.org/ml/gcc-patches/2004-12/msg00655.html

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |sayle at gcc dot gnu dot org
                   |dot org                     |
             Status|NEW                         |ASSIGNED
            Summary|[4.0/3.4 Regression] 'while'|[3.4/4.0 Regression] 'while'
                   |loop performace regression  |loop performace regression
                   |on avr target               |on avr target


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18002

[Bug target/18002] [3.4/4.0 Regression] 'while' loop performace regression on avr target

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2004-12-11 01:49 -------
Subject: Bug 18002

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	sayle@gcc.gnu.org	2004-12-11 01:49:06

Modified files:
	gcc            : ChangeLog dojump.c 

Log message:
	PR target/18002
	PR middle-end/18424
	* dojump.c (do_jump): When attempting to reverse the effects of
	fold_single_bit_test, we need to STRIP_NOPS and narrowing type
	conversions, and handle BIT_XOR_EXPR that's used to invert the
	sense of the single bit test.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&r1=2.6778&r2=2.6779
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/dojump.c.diff?cvsroot=gcc&r1=1.32&r2=1.33



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18002

[Bug target/18002] [3.4 Regression] 'while' loop performace regression on avr target

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-12-11 07:41 -------
Fixed on the mainline at least.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[3.4/4.0 Regression] 'while'|[3.4 Regression] 'while'
                   |loop performace regression  |loop performace regression
                   |on avr target               |on avr target


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18002

[Bug target/18002] [3.4 Regression] 'while' loop performace regression on avr target

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2004-12-14 01:47 -------
Subject: Bug 18002

CVSROOT:	/cvs/gcc
Module name:	gcc
Branch: 	gcc-3_4-branch
Changes by:	sayle@gcc.gnu.org	2004-12-14 01:47:35

Modified files:
	gcc            : ChangeLog dojump.c Makefile.in 

Log message:
	PR target/18002
	PR middle-end/18424
	Backport from mainline
	
	2004-03-20  Richard Sandiford  <rsandifo@redhat.com>
	* Makefile.in (dojump.o): Depend on $(GGC_H) and dojump.h.
	(GTFILES): Add $(srcdir)/dojump.h.
	(gt-dojump.h): New dependency.
	* dojump.c (and_reg, and_test, shift_test): New static variables.
	(prefer_and_bit_test): New function.
	(do_jump): Use it to choose between (X & (1 << C)) and (X >> C) & 1.
	
	2004-03-21  Andrew Pinski  <pinskia@gcc.gnu.org>
	* dojump.c (prefer_and_bit_test): Fix which part of
	the and_test is replaced.
	
	2004-12-10  Roger Sayle  <roger@eyesopen.com>
	* dojump.c (do_jump): When attempting to reverse the effects of
	fold_single_bit_test, we need to STRIP_NOPS and narrowing type
	conversions, and handle BIT_XOR_EXPR that's used to invert the
	sense of the single bit test.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&only_with_tag=gcc-3_4-branch&r1=2.2326.2.730&r2=2.2326.2.731
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/dojump.c.diff?cvsroot=gcc&only_with_tag=gcc-3_4-branch&r1=1.9.4.1&r2=1.9.4.2
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/Makefile.in.diff?cvsroot=gcc&only_with_tag=gcc-3_4-branch&r1=1.1223.2.20&r2=1.1223.2.21



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18002

[Bug target/18002] [3.4 Regression] 'while' loop performace regression on avr target

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-12-14 02:08 -------
Fixed.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18002