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[Bug middle-end/23181] [4.1 Regression] Slowdown of the bresenham line drawing by roughly 20%
- From: "steven at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 7 Jan 2006 18:23:03 -0000
- Subject: [Bug middle-end/23181] [4.1 Regression] Slowdown of the bresenham line drawing by roughly 20%
- References: <bug-23181-176@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #21 from steven at gcc dot gnu dot org 2006-01-07 18:23 -------
Using ``.ident "GCC: (GNU) 4.1.0 20060107 (prerelease)"'' on AMD64 with -m32,
I get the following assembly outputs:
options: -O2 -fno-tree-dominator-opts
.L2:
movl $videoram, %eax
movl $-2, %edx
jmp .L5
.p2align 4,,7
.L14:
addl $18, %edx
.L5:
testl %edx, %edx
movb $5, (%eax)
js .L6
addl $21, %eax
subl $40, %edx
.L6:
incl %eax
cmpl %eax, %ecx
jne .L14
incl %ebx
movb $5, videoram+209
cmpl $10000000, %ebx
jne .L2
options: -O2
.L2:
movb $5, videoram
movl $videoram, %eax
movl $-2, %edx
.L18:
incl %eax
cmpl %eax, %ecx
je .L20
.p2align 4,,7
.L5:
addl $18, %edx
movb $5, (%eax)
js .L18
addl $21, %eax
subl $40, %edx
incl %eax
cmpl %eax, %ecx
jne .L5
.L20:
incl %ebx
movb $5, videoram+209
cmpl $10000000, %ebx
jne .L2
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23181