http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55190
Bug #: 55190
Summary: [SH] ivopts causes loop setup bloat
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: target
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: olege...@gcc.gnu.org
Target: sh*-*-*
The following code:
struct X
{
int a, b, c, d, e;
};
int test (X* x, unsigned int c)
{
int s = 0;
unsigned int i;
for (i = 0; i < c; ++i)
s += x[i].b;
return s;
}
results in:
tst r5,r5
bt/s .L4
mov r5,r1
shll2 r1
add r5,r1
mov.l .L9,r2
shll2 r1
add #-20,r1
shlr2 r1
mul.l r2,r1
mov.l .L10,r2
add #4,r4
mov #0,r0
sts macl,r1
and r2,r1
add #1,r1
.L3:
mov.l @r4,r2
dt r1
add #20,r4
bf/s .L3
add r2,r0
rts
nop
.L4:
rts
mov #0,r0
.L11:
.align 2
.L9:
.long 214748365
.L10:
.long 1073741823
In such cases, the loop counter setup code that seems to be produced by ivopts
can be left out, which would result in something like:
tst r5,r5
bt/s .L15
add #4,r4
mov #0,r0
.L14:
mov.l @r4,r1
dt r5
add #20,r4
bf/s .L14
add r1,r0
rts
nop
.L15:
rts
mov #0,r0
