On Sun, 17 Sept 2023 at 20:11, Richard Sandiford <richard.sandif...@arm.com> wrote: > > Prathamesh Kulkarni <prathamesh.kulka...@linaro.org> writes: > > Hi, > > After 27de9aa152141e7f3ee66372647d0f2cd94c4b90, there's a following > > regression: > > FAIL: gcc.target/aarch64/vect_copy_lane_1.c scan-assembler-times > > ins\\tv0.s\\[1\\], v1.s\\[0\\] 3 > > > > This happens because for the following function from vect_copy_lane_1.c: > > float32x2_t > > __attribute__((noinline, noclone)) test_copy_lane_f32 (float32x2_t a, > > float32x2_t b) > > { > > return vcopy_lane_f32 (a, 1, b, 0); > > } > > > > Before 27de9aa152141e7f3ee66372647d0f2cd94c4b90, > > it got lowered to following sequence in .optimized dump: > > <bb 2> [local count: 1073741824]: > > _4 = BIT_FIELD_REF <b_3(D), 32, 0>; > > __a_5 = BIT_INSERT_EXPR <a_2(D), _4, 32>; > > return __a_5; > > > > The above commit simplifies BIT_FIELD_REF + BIT_INSERT_EXPR > > to vector permutation and now thus gets lowered to: > > > > <bb 2> [local count: 1073741824]: > > __a_4 = VEC_PERM_EXPR <a_2(D), b_3(D), { 0, 2 }>; > > return __a_4; > > > > Since we give higher priority to aarch64_evpc_zip over aarch64_evpc_ins > > in aarch64_expand_vec_perm_const_1, it now generates: > > > > test_copy_lane_f32: > > zip1 v0.2s, v0.2s, v1.2s > > ret > > > > Similarly for test_copy_lane_[us]32. > > Yeah, I suppose this choice is at least as good as INS. It has the advantage > that the source and destination don't need to be tied. For example: > > int32x2_t f(int32x2_t a, int32x2_t b, int32x2_t c) { > return vcopy_lane_s32 (b, 1, c, 0); > } > > used to be: > > f: > mov v0.8b, v1.8b > ins v0.s[1], v2.s[0] > ret > > but is now: > > f: > zip1 v0.2s, v1.2s, v2.2s > ret > > > The attached patch adjusts the tests to reflect the change in code-gen > > and the tests pass. > > OK to commit ? > > > > Thanks, > > Prathamesh > > > > diff --git a/gcc/testsuite/gcc.target/aarch64/vect_copy_lane_1.c > > b/gcc/testsuite/gcc.target/aarch64/vect_copy_lane_1.c > > index 2848be564d5..811dc678b92 100644 > > --- a/gcc/testsuite/gcc.target/aarch64/vect_copy_lane_1.c > > +++ b/gcc/testsuite/gcc.target/aarch64/vect_copy_lane_1.c > > @@ -22,7 +22,7 @@ BUILD_TEST (uint16x4_t, uint16x4_t, , , u16, 3, 2) > > BUILD_TEST (float32x2_t, float32x2_t, , , f32, 1, 0) > > BUILD_TEST (int32x2_t, int32x2_t, , , s32, 1, 0) > > BUILD_TEST (uint32x2_t, uint32x2_t, , , u32, 1, 0) > > -/* { dg-final { scan-assembler-times "ins\\tv0.s\\\[1\\\], v1.s\\\[0\\\]" > > 3 } } */ > > +/* { dg-final { scan-assembler-times "zip1\\tv0.2s, v0.2s, v1.2s" 3 } } */ > > BUILD_TEST (int64x1_t, int64x1_t, , , s64, 0, 0) > > BUILD_TEST (uint64x1_t, uint64x1_t, , , u64, 0, 0) > > BUILD_TEST (float64x1_t, float64x1_t, , , f64, 0, 0) > > OK, thanks. Thanks, committed to trunk in 98c25cfc79a21886de7342fb563c4eb3c3d5f4e9.
Thanks, Prathamesh > > Richard