------- Comment #12 from steven at gcc dot gnu dot org 2010-02-04 14:54 -------
With the patches from bug 42617 applied, I get the following:
.file "tst.c"
.text
.align 2
.global Unroll
.type Unroll, %function
Unroll:
@ args = 0, pretend = 0, frame = 0
@ frame_needed = 0, uses_anonymous_args = 0
@ link register save eliminated.
mov r0, r0, asl #16
stmfd sp!, {r4, r5, r6, r7, r8}
mov r0, r0, asr #16
add r8, r1, #256
.L2:
ldr ip, [r1, #0]
mov r7, r1
mul r2, ip, r0
str r2, [r7], #4
ldr r3, [r1, #4]
ldr r5, [r7, #4]
mul r6, r3, r0
str r6, [r7, #0]
ldr r4, [r1, #12]
ldr ip, [r1, #16]
add r2, r1, #20
ldmia r2, {r2, r3, r7} @ phole ldm
mul r6, r5, r0
mul r5, r4, r0
mul r4, ip, r0
mul ip, r2, r0
mul r2, r3, r0
mul r3, r7, r0
str r6, [r1, #8]
str r5, [r1, #12]
str r4, [r1, #16]
str ip, [r1, #20]
str r2, [r1, #24]
add r1, r1, #32
cmp r1, r8
str r3, [r1, #-4]
bne .L2
ldmfd sp!, {r4, r5, r6, r7, r8}
bx lr
.size Unroll, .-Unroll
.ident "GCC: (GNU) 4.5.0 20100204 (experimental) [trunk revision
156492]"
(flags: -std=c99 -mcpu=arm9 -O2 -funroll-loops)
This is good but not perfect.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36712
