...and here's the missing test case.
-- Michael
On Wed, Oct 19, 2011 at 11:38 AM, Michael Hope <michael.h...@linaro.org> wrote:
> Following on from last night's performance call, I had a look at how
> 64 bit integer operations are mapped to NEON instructions. The
> summary is:
>
> * add - fine
> * subtract - fine
> * bitwise and - fine
> * bitwise or - fine
> * bitwise xor - fine
> * multiply - can't as the instruction tops out at 32 bits. Might be
> able to compose using VMLAL
> * div, mod - no instruction
> * negate - instruction tops out at 32 bits, but could be turned into
> vmov #0, vsub
> * left shift constant - missing
> * right shift constant - missing
> * right arithmetic shift constant - missing
> * left shift register - missing
> * right shift register - tricky, as you do this as a left shift -register
> * not - no instruction, but could be done through a vceq, #0?
> * bitwise not - missing
>
> I also noticed that the replicated constants aren't being used. A
> pre-increment is load constant pool; vadd but could be done as a vmov,
> #-1; vsub. The same with pre-decrement - it could be done as a vmov,
> #-1; vadd.
>
> This seems worth blueprinting.
>
> -- Michael
>
typedef long long type;
typedef unsigned long long utype;
#define TEST(name, op) \
void op_##name(type *left, type *right, type *result) { op; }
TEST(add, *result = *left + *right)
TEST(sub, *result = *left - *right)
TEST(mul, *result = *left * *right)
TEST(div, *result = *left / *right)
TEST(mod, *result = *left % *right)
TEST(inc, *result = ++(*left))
TEST(dec, *result = --(*left))
TEST(neg, *result = -*left)
TEST(lshiftc, *result = *left << 5)
TEST(rshiftc, *result = *left >> 5)
TEST(lshift, *result = *left << *right)
TEST(rshift, *result = *left >> *right)
TEST(urshiftc, *result = (utype)*left >> 5)
TEST(urshift, *result = (utype)*left >> *right)
TEST(not, *result = !*left)
TEST(bitnot, *result = ~*left)
TEST(and, *result = *left & *right)
TEST(or, *result = *left | *right)
TEST(xor, *result = *left ^ *right)
TEST(assign, *result = *left)
TEST(const1, *result = 0 - *left)
TEST(const2, *result = *left + 0x100000001LL)
TEST(const3, *result = *left + 0xFFFFFFFFFFFFFFFFLL)
/* Bad:
mul - can't directly, tops out at 32 bit
div - none
mod - none
inc is a add 1 from constant pool
dec is a add -1 from constant pool
neg - tops out at 32 bit
lshiftc
{u}rshiftc
lshift
{u}rshift
not
bitnot
add doesn't recognise replicated constants
vshr, reg doesn't exist but can be done through vshl, -shift
*/
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