The assembly emitted for some arm neon fma intrinsics contains function calls

[hkratz]

vfma_n_f32, vfmaq_n_f32, vfms_n_f32 and vfms_n_f32are affected.

From a CI with inlining check enabled (https://github.com/rust-lang/stdarch/runs/3547875318):

---- core_arch::arm_shared::neon::generated::assert_vfma_n_f32_vfma stdout ----
disassembly for stdarch_test_shim_vfma_n_f32_vfma: 
	 0: push {fp, lr}
	 1: vpush {d8-d9}
	 2: sub sp, sp, #8
	 3: ldr r0, [pc, #56] ; 395e0 <stdarch_test_shim_vfma_n_f32_vfma+0x4c>
	 4: vorr d9, d0, d0
	 5: ldr r1, [pc, #52] ; 395e4 <stdarch_test_shim_vfma_n_f32_vfma+0x50>
	 6: vmov.f32 s0, s4
	 7: add r0, pc, r0
	 8: vorr d8, d1, d1
	 9: ldr r1, [pc, r1]
	10: str r0, [r1]
	11: mov r0, sp
	12: bl 34030 <_ZN9core_arch9core_arch10arm_shared4neon10vdup_n_f3217h6b11480dbcf9ce6fE>
	13: vldr d16, [sp]
	14: vfma.f32 d9, d8, d16
	15: vorr d0, d9, d9
	16: add sp, sp, #8
	17: vpop {d8-d9}
	18: pop {fp, pc}
	19: .word 0x0010780f
	20: .word 0x001be9d8
thread 'core_arch::arm_shared::neon::generated::assert_vfma_n_f32_vfma' panicked at 'instruction found, but the disassembly contains subroutine call instructions, which hint that inlining failed', crates/stdarch-test/src/lib.rs:177:9
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

---- core_arch::arm_shared::neon::generated::assert_vfmaq_n_f32_vfma stdout ----
disassembly for stdarch_test_shim_vfmaq_n_f32_vfma: 
	 0: push {r4, lr}
	 1: vpush {d8-d11}
	 2: sub sp, sp, #16
	 3: ldr r0, [pc, #60] ; 3958c <stdarch_test_shim_vfmaq_n_f32_vfma+0x50>
	 4: vorr q5, q0, q0
	 5: ldr r1, [pc, #56] ; 39590 <stdarch_test_shim_vfmaq_n_f32_vfma+0x54>
	 6: vmov.f32 s0, s8
	 7: add r0, pc, r0
	 8: mov r4, sp
	 9: vorr q4, q1, q1
	10: ldr r1, [pc, r1]
	11: str r0, [r1]
	12: mov r0, r4
	13: bl 34024 <_ZN9core_arch9core_arch10arm_shared4neon11vdupq_n_f3217h03e9053c684c2898E>
	14: vld1.64 {d16-d17}, [r4]
	15: vfma.f32 q5, q4, q8
	16: vorr q0, q5, q5
	17: add sp, sp, #16
	18: vpop {d8-d11}
	19: pop {r4, pc}
	20: .word 0x0010780d
	21: .word 0x001bea2c
thread 'core_arch::arm_shared::neon::generated::assert_vfmaq_n_f32_vfma' panicked at 'instruction found, but the disassembly contains subroutine call instructions, which hint that inlining failed', crates/stdarch-test/src/lib.rs:177:9

---- core_arch::arm_shared::neon::generated::assert_vfms_n_f32_vfms stdout ----
disassembly for stdarch_test_shim_vfms_n_f32_vfms: 
	 0: push {fp, lr}
	 1: vpush {d8-d9}
	 2: sub sp, sp, #8
	 3: ldr r0, [pc, #56] ; 394ec <stdarch_test_shim_vfms_n_f32_vfms+0x4c>
	 4: vorr d9, d0, d0
	 5: ldr r1, [pc, #52] ; 394f0 <stdarch_test_shim_vfms_n_f32_vfms+0x50>
	 6: vmov.f32 s0, s4
	 7: add r0, pc, r0
	 8: vorr d8, d1, d1
	 9: ldr r1, [pc, r1]
	10: str r0, [r1]
	11: mov r0, sp
	12: bl 34030 <_ZN9core_arch9core_arch10arm_shared4neon10vdup_n_f3217h6b11480dbcf9ce6fE>
	13: vldr d16, [sp]
	14: vfms.f32 d9, d8, d16
	15: vorr d0, d9, d9
	16: add sp, sp, #8
	17: vpop {d8-d9}
	18: pop {fp, pc}
	19: .word 0x001077c9
	20: .word 0x001beacc
thread 'core_arch::arm_shared::neon::generated::assert_vfms_n_f32_vfms' panicked at 'instruction found, but the disassembly contains subroutine call instructions, which hint that inlining failed', crates/stdarch-test/src/lib.rs:177:9

---- core_arch::arm_shared::neon::generated::assert_vfmsq_n_f32_vfms stdout ----
disassembly for stdarch_test_shim_vfmsq_n_f32_vfms: 
	 0: push {r4, lr}
	 1: vpush {d8-d11}
	 2: sub sp, sp, #16
	 3: ldr r0, [pc, #60] ; 39498 <stdarch_test_shim_vfmsq_n_f32_vfms+0x50>
	 4: vorr q5, q0, q0
	 5: ldr r1, [pc, #56] ; 3949c <stdarch_test_shim_vfmsq_n_f32_vfms+0x54>
	 6: vmov.f32 s0, s8
	 7: add r0, pc, r0
	 8: mov r4, sp
	 9: vorr q4, q1, q1
	10: ldr r1, [pc, r1]
	11: str r0, [r1]
	12: mov r0, r4
	13: bl 34024 <_ZN9core_arch9core_arch10arm_shared4neon11vdupq_n_f3217h03e9053c684c2898E>
	14: vld1.64 {d16-d17}, [r4]
	15: vfms.f32 q5, q4, q8
	16: vorr q0, q5, q5
	17: add sp, sp, #16
	18: vpop {d8-d11}
	19: pop {r4, pc}
	20: .word 0x001077c7
	21: .word 0x001beb20
thread 'core_arch::arm_shared::neon::generated::assert_vfmsq_n_f32_vfms' panicked at 'instruction found, but the disassembly contains subroutine call instructions, which hint that inlining failed', crates/stdarch-test/src/lib.rs:177:9

cc @SparrowLii

[hkratz]

The problem is that the VFMA functions have target_feature(enable = "fp-armv8,v8") while the called functions vdup_n_f32 and vdupq_n_f32 are target_feature(enable = "v7"). Using private _v8 variants of those functions causes them to be inlined.

Before I submit a PR though... Isn't VFMA already supported with vfp4+neon? Should we use v7,vfp4 instead of fp-armv8 and v8?