[Bug tree-optimization/23181] [4.1 Regression] Dominator opts slows down bresenham line drawing by roughly 20%

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-08-01 14:42 -------
It makes worse code on ppc also:
L5:
	stb r8,1(r11)
	blt- cr0,L6
	addi r0,r11,22
	addi r10,r9,-22
L6:
	mr r11,r0
	mr r9,r10
	addi r0,r11,1
	addic. r10,r9,18
	cmpw cr7,r2,r0
	bne+ cr7,L5

vs:
L5:
	cmpwi cr7,r11,0
	stb r0,0(r9)
	blt- cr7,L6
	addi r9,r9,21
	addi r11,r11,-40
L6:
	addi r9,r9,1
	addi r11,r11,18
	cmpw cr7,r2,r9
	bne+ cr7,L5

Notice how there is no mrs in the second one, the second one is with -fno-tree-dominator-opts.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |law at gcc dot gnu dot org
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
 GCC target triplet|i686-linux                  |
           Keywords|                            |missed-optimization
   Last reconfirmed|0000-00-00 00:00:00         |2005-08-01 14:42:37
               date|                            |
            Summary|Dominator opts slows down   |[4.1 Regression] Dominator
                   |bresenham line drawing by   |opts slows down bresenham
                   |roughly 20%                 |line drawing by roughly 20%
   Target Milestone|---                         |4.1.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23181