On Tue, 1 Jun 2021 at 16:03, Prathamesh Kulkarni
<prathamesh.kulka...@linaro.org> wrote:
>
> Hi,
> As mentioned in PR, for following test-case:
>
> #include <arm_neon.h>
>
> uint32x2_t f1(float32x2_t a, float32x2_t b)
> {
> return vabs_f32 (a) >= vabs_f32 (b);
> }
>
> uint32x2_t f2(float32x2_t a, float32x2_t b)
> {
> return (uint32x2_t) __builtin_neon_vcagev2sf (a, b);
> }
>
> We generate vacge for f2, but with -ffast-math, we generate following for f1:
> f1:
> vabs.f32 d1, d1
> vabs.f32 d0, d0
> vcge.f32 d0, d0, d1
> bx lr
>
> This happens because, the middle-end inverts the comparison to b <= a,
> .optimized dump:
> _8 = __builtin_neon_vabsv2sf (a_4(D));
> _7 = __builtin_neon_vabsv2sf (b_5(D));
> _1 = _7 <= _8;
> _2 = VIEW_CONVERT_EXPR<vector(2) int>(_1);
> _6 = VIEW_CONVERT_EXPR<uint32x2_t>(_2);
> return _6;
>
> and combine fails to match the following pattern:
> (set (reg:V2SI 121)
> (neg:V2SI (le:V2SI (abs:V2SF (reg:V2SF 123))
> (abs:V2SF (reg:V2SF 122)))))
>
> because neon_vca<cmp_op><mode> pattern has GTGE code iterator.
> The attached patch adjusts the neon_vca patterns to use GLTE instead
> similar to neon_vca<cmp_op><mode>_fp16insn, and removes NEON_VACMP iterator.
> Code-gen with patch:
> f1:
> vacle.f32 d0, d1, d0
> bx lr
>
> Bootstrapped + tested on arm-linux-gnueabihf and cross-tested on arm*-*-*.
> OK to commit ?
ping https://gcc.gnu.org/pipermail/gcc-patches/2021-June/571568.html
Thanks,
Prathamesh
>
> Thanks,
> Prathamesh
