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[Bug target/63321] [SH] Unused T bit result of shll / shlr insns
- From: "olegendo at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Sun, 26 Jul 2015 06:02:03 +0000
- Subject: [Bug target/63321] [SH] Unused T bit result of shll / shlr insns
- Auto-submitted: auto-generated
- References: <bug-63321-4 at http dot gcc dot gnu dot org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63321
--- Comment #7 from Oleg Endo <olegendo at gcc dot gnu.org> ---
Another example:
unsigned int
count_trailing_nonzero_bits (unsigned int v, unsigned int c)
{
c += v & 1;
v >>= 1;
c += v & 1;
v >>= 1;
c += v & 1;
v >>= 1;
c += v & 1;
v >>= 1;
c += v & 1;
v >>= 1;
c += v & 1;
v >>= 1;
c += v & 1;
v >>= 1;
c += v & 1;
v >>= 1;
return c;
}
ideally should compile to:
mov #0,r1
shlr r4
movt r0
shlr r4
addc r1,r0
shlr r4
addc r1,r0
shlr r4
addc r1,r0
shlr r4
addc r1,r0
shlr r4
addc r1,r0
shlr r4
addc r1,r0
shlr r4
addc r1,r0