[AArch64] Add tests for fused FP literals. NFC (#106731)

This is for an upcoming change to the threshold on Apple targets for
using a constant pool for FP literals versus building them with integer
moves.

This file is based on literal_pools_float.ll. I tried to bolt on to the
existing test, but it got messy as that file is already testing a matrix
of combinations, so creating this new file instead.

Author: citymarina

llvm/test/CodeGen/AArch64/literal_pools_float_apple.ll

@@ -0,0 +1,128 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc -verify-machineinstrs -mtriple=aarch64-none-linux-gnu < %s | FileCheck %s
+; RUN: llc -verify-machineinstrs -mtriple=arm64-apple-macosx -mcpu=apple-m1 < %s | FileCheck %s --check-prefix=APPLE
+
+define float @float_0mov() {
+; CHECK-LABEL: float_0mov:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    fmov s0, #1.00000000
+; CHECK-NEXT:    ret
+;
+; APPLE-LABEL: float_0mov:
+; APPLE:       ; %bb.0:
+; APPLE-NEXT:    fmov s0, #1.00000000
+; APPLE-NEXT:    ret
+  ret float 1.0
+}
+
+define float @float_1mov() {
+; CHECK-LABEL: float_1mov:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    mov w8, #2143289344 // =0x7fc00000
+; CHECK-NEXT:    fmov s0, w8
+; CHECK-NEXT:    ret
+;
+; APPLE-LABEL: float_1mov:
+; APPLE:       ; %bb.0:
+; APPLE-NEXT:    mov w8, #2143289344 ; =0x7fc00000
+; APPLE-NEXT:    fmov s0, w8
+; APPLE-NEXT:    ret
+  ret float 0x7FF8000000000000
+}
+
+define float @float_2mov() {
+; CHECK-LABEL: float_2mov:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    mov w8, #34952 // =0x8888
+; CHECK-NEXT:    movk w8, #32704, lsl #16
+; CHECK-NEXT:    fmov s0, w8
+; CHECK-NEXT:    ret
+;
+; APPLE-LABEL: float_2mov:
+; APPLE:       ; %bb.0:
+; APPLE-NEXT:    mov w8, #34952 ; =0x8888
+; APPLE-NEXT:    movk w8, #32704, lsl #16
+; APPLE-NEXT:    fmov s0, w8
+; APPLE-NEXT:    ret
+  ret float 0x7FF8111100000000
+}
+
+define double @double_0mov() {
+; CHECK-LABEL: double_0mov:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    fmov d0, #1.00000000
+; CHECK-NEXT:    ret
+;
+; APPLE-LABEL: double_0mov:
+; APPLE:       ; %bb.0:
+; APPLE-NEXT:    fmov d0, #1.00000000
+; APPLE-NEXT:    ret
+  ret double 1.0
+}
+
+define double @double_1mov() {
+; CHECK-LABEL: double_1mov:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    mov x8, #4096 // =0x1000
+; CHECK-NEXT:    fmov d0, x8
+; CHECK-NEXT:    ret
+;
+; APPLE-LABEL: double_1mov:
+; APPLE:       ; %bb.0:
+; APPLE-NEXT:    mov x8, #4096 ; =0x1000
+; APPLE-NEXT:    fmov d0, x8
+; APPLE-NEXT:    ret
+  ret double 0x1000
+}
+
+define double @double_2mov() {
+; CHECK-LABEL: double_2mov:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    mov x8, #4096 // =0x1000
+; CHECK-NEXT:    movk x8, #8192, lsl #16
+; CHECK-NEXT:    fmov d0, x8
+; CHECK-NEXT:    ret
+;
+; APPLE-LABEL: double_2mov:
+; APPLE:       ; %bb.0:
+; APPLE-NEXT:    mov x8, #4096 ; =0x1000
+; APPLE-NEXT:    movk x8, #8192, lsl #16
+; APPLE-NEXT:    fmov d0, x8
+; APPLE-NEXT:    ret
+  ret double 0x20001000
+}
+
+define double @double_3mov() {
+; CHECK-LABEL: double_3mov:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    adrp x8, .LCPI6_0
+; CHECK-NEXT:    ldr d0, [x8, :lo12:.LCPI6_0]
+; CHECK-NEXT:    ret
+;
+; APPLE-LABEL: double_3mov:
+; APPLE:       ; %bb.0:
+; APPLE-NEXT:    mov x8, #4096 ; =0x1000
+; APPLE-NEXT:    movk x8, #8192, lsl #16
+; APPLE-NEXT:    movk x8, #12288, lsl #32
+; APPLE-NEXT:    fmov d0, x8
+; APPLE-NEXT:    ret
+  ret double 0x300020001000
+}
+
+define double @double_4mov() {
+; CHECK-LABEL: double_4mov:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    adrp x8, .LCPI7_0
+; CHECK-NEXT:    ldr d0, [x8, :lo12:.LCPI7_0]
+; CHECK-NEXT:    ret
+;
+; APPLE-LABEL: double_4mov:
+; APPLE:       ; %bb.0:
+; APPLE-NEXT:    mov x8, #4096 ; =0x1000
+; APPLE-NEXT:    movk x8, #8192, lsl #16
+; APPLE-NEXT:    movk x8, #12288, lsl #32
+; APPLE-NEXT:    movk x8, #16384, lsl #48
+; APPLE-NEXT:    fmov d0, x8
+; APPLE-NEXT:    ret
+  ret double 0x4000300020001000
+}