[llvm] [AArch64][GlobalISel] Improve and expand fcopysign lowering (PR #71283)

[Matt Arsenault via llvm-commits]

================
@@ -55,64 +51,109 @@ entry:
 }
 
 define half @copysign_f16(half %a, half %b) {
-; CHECK-LABEL: copysign_f16:
-; CHECK:       // %bb.0: // %entry
-; CHECK-NEXT:    fcvt s1, h1
-; CHECK-NEXT:    fcvt s0, h0
-; CHECK-NEXT:    mvni v2.4s, #128, lsl #24
-; CHECK-NEXT:    bif v0.16b, v1.16b, v2.16b
-; CHECK-NEXT:    fcvt h0, s0
-; CHECK-NEXT:    ret
+; CHECK-SD-LABEL: copysign_f16:
+; CHECK-SD:       // %bb.0: // %entry
+; CHECK-SD-NEXT:    fcvt s1, h1
+; CHECK-SD-NEXT:    fcvt s0, h0
+; CHECK-SD-NEXT:    mvni v2.4s, #128, lsl #24
+; CHECK-SD-NEXT:    bif v0.16b, v1.16b, v2.16b
+; CHECK-SD-NEXT:    fcvt h0, s0
+; CHECK-SD-NEXT:    ret
+;
+; CHECK-GI-LABEL: copysign_f16:
+; CHECK-GI:       // %bb.0: // %entry
+; CHECK-GI-NEXT:    mvni v2.4h, #128, lsl #8
+; CHECK-GI-NEXT:    // kill: def $h0 killed $h0 def $d0
+; CHECK-GI-NEXT:    // kill: def $h1 killed $h1 def $d1
+; CHECK-GI-NEXT:    bif v0.8b, v1.8b, v2.8b
+; CHECK-GI-NEXT:    // kill: def $h0 killed $h0 killed $q0
+; CHECK-GI-NEXT:    ret
 entry:
   %c = call half @llvm.copysign.f16(half %a, half %b)
   ret half %c
 }
 
 define <2 x double> @copysign_v2f64(<2 x double> %a, <2 x double> %b) {
-; CHECK-LABEL: copysign_v2f64:
-; CHECK:       // %bb.0: // %entry
-; CHECK-NEXT:    movi v2.2d, #0xffffffffffffffff
-; CHECK-NEXT:    fneg v2.2d, v2.2d
-; CHECK-NEXT:    bif v0.16b, v1.16b, v2.16b
-; CHECK-NEXT:    ret
+; CHECK-SD-LABEL: copysign_v2f64:
+; CHECK-SD:       // %bb.0: // %entry
+; CHECK-SD-NEXT:    movi v2.2d, #0xffffffffffffffff
+; CHECK-SD-NEXT:    fneg v2.2d, v2.2d
+; CHECK-SD-NEXT:    bif v0.16b, v1.16b, v2.16b
+; CHECK-SD-NEXT:    ret
+;
+; CHECK-GI-LABEL: copysign_v2f64:
+; CHECK-GI:       // %bb.0: // %entry
+; CHECK-GI-NEXT:    adrp x8, .LCPI3_0
+; CHECK-GI-NEXT:    ldr q2, [x8, :lo12:.LCPI3_0]
+; CHECK-GI-NEXT:    bif v0.16b, v1.16b, v2.16b
+; CHECK-GI-NEXT:    ret
 entry:
   %c = call <2 x double> @llvm.copysign.v2f64(<2 x double> %a, <2 x double> %b)
   ret <2 x double> %c
 }
 
 define <3 x double> @copysign_v3f64(<3 x double> %a, <3 x double> %b) {
-; CHECK-LABEL: copysign_v3f64:
-; CHECK:       // %bb.0: // %entry
-; CHECK-NEXT:    movi v6.2d, #0xffffffffffffffff
-; CHECK-NEXT:    // kill: def $d3 killed $d3 def $q3
-; CHECK-NEXT:    // kill: def $d1 killed $d1 def $q1
-; CHECK-NEXT:    // kill: def $d0 killed $d0 def $q0
-; CHECK-NEXT:    // kill: def $d4 killed $d4 def $q4
-; CHECK-NEXT:    // kill: def $d2 killed $d2 def $q2
-; CHECK-NEXT:    // kill: def $d5 killed $d5 def $q5
-; CHECK-NEXT:    mov v3.d[1], v4.d[0]
-; CHECK-NEXT:    mov v0.d[1], v1.d[0]
-; CHECK-NEXT:    fneg v1.2d, v6.2d
-; CHECK-NEXT:    bif v0.16b, v3.16b, v1.16b
-; CHECK-NEXT:    bif v2.16b, v5.16b, v1.16b
-; CHECK-NEXT:    // kill: def $d2 killed $d2 killed $q2
-; CHECK-NEXT:    ext v1.16b, v0.16b, v0.16b, #8
-; CHECK-NEXT:    // kill: def $d0 killed $d0 killed $q0
-; CHECK-NEXT:    // kill: def $d1 killed $d1 killed $q1
-; CHECK-NEXT:    ret
+; CHECK-SD-LABEL: copysign_v3f64:
+; CHECK-SD:       // %bb.0: // %entry
+; CHECK-SD-NEXT:    movi v6.2d, #0xffffffffffffffff
+; CHECK-SD-NEXT:    // kill: def $d3 killed $d3 def $q3
+; CHECK-SD-NEXT:    // kill: def $d1 killed $d1 def $q1
+; CHECK-SD-NEXT:    // kill: def $d0 killed $d0 def $q0
+; CHECK-SD-NEXT:    // kill: def $d4 killed $d4 def $q4
+; CHECK-SD-NEXT:    // kill: def $d2 killed $d2 def $q2
+; CHECK-SD-NEXT:    // kill: def $d5 killed $d5 def $q5
+; CHECK-SD-NEXT:    mov v3.d[1], v4.d[0]
+; CHECK-SD-NEXT:    mov v0.d[1], v1.d[0]
+; CHECK-SD-NEXT:    fneg v1.2d, v6.2d
+; CHECK-SD-NEXT:    bif v0.16b, v3.16b, v1.16b
+; CHECK-SD-NEXT:    bif v2.16b, v5.16b, v1.16b
+; CHECK-SD-NEXT:    // kill: def $d2 killed $d2 killed $q2
+; CHECK-SD-NEXT:    ext v1.16b, v0.16b, v0.16b, #8
+; CHECK-SD-NEXT:    // kill: def $d0 killed $d0 killed $q0
+; CHECK-SD-NEXT:    // kill: def $d1 killed $d1 killed $q1
+; CHECK-SD-NEXT:    ret
+;
+; CHECK-GI-LABEL: copysign_v3f64:
+; CHECK-GI:       // %bb.0: // %entry
+; CHECK-GI-NEXT:    // kill: def $d0 killed $d0 def $q0
+; CHECK-GI-NEXT:    // kill: def $d3 killed $d3 def $q3
+; CHECK-GI-NEXT:    // kill: def $d1 killed $d1 def $q1
+; CHECK-GI-NEXT:    // kill: def $d4 killed $d4 def $q4
+; CHECK-GI-NEXT:    adrp x8, .LCPI4_0
+; CHECK-GI-NEXT:    fmov x9, d5
+; CHECK-GI-NEXT:    mov v0.d[1], v1.d[0]
+; CHECK-GI-NEXT:    mov v3.d[1], v4.d[0]
+; CHECK-GI-NEXT:    ldr q1, [x8, :lo12:.LCPI4_0]
+; CHECK-GI-NEXT:    fmov x8, d2
+; CHECK-GI-NEXT:    and x9, x9, #0x8000000000000000
+; CHECK-GI-NEXT:    bif v0.16b, v3.16b, v1.16b
+; CHECK-GI-NEXT:    and x8, x8, #0x7fffffffffffffff
+; CHECK-GI-NEXT:    orr x8, x8, x9
+; CHECK-GI-NEXT:    fmov d2, x8
+; CHECK-GI-NEXT:    mov d1, v0.d[1]
+; CHECK-GI-NEXT:    // kill: def $d0 killed $d0 killed $q0
+; CHECK-GI-NEXT:    ret
 entry:
   %c = call <3 x double> @llvm.copysign.v3f64(<3 x double> %a, <3 x double> %b)
   ret <3 x double> %c
 }
 
 define <4 x double> @copysign_v4f64(<4 x double> %a, <4 x double> %b) {
-; CHECK-LABEL: copysign_v4f64:
-; CHECK:       // %bb.0: // %entry
-; CHECK-NEXT:    movi v4.2d, #0xffffffffffffffff
-; CHECK-NEXT:    fneg v4.2d, v4.2d
-; CHECK-NEXT:    bif v0.16b, v2.16b, v4.16b
-; CHECK-NEXT:    bif v1.16b, v3.16b, v4.16b
-; CHECK-NEXT:    ret
+; CHECK-SD-LABEL: copysign_v4f64:
+; CHECK-SD:       // %bb.0: // %entry
+; CHECK-SD-NEXT:    movi v4.2d, #0xffffffffffffffff
+; CHECK-SD-NEXT:    fneg v4.2d, v4.2d
+; CHECK-SD-NEXT:    bif v0.16b, v2.16b, v4.16b
+; CHECK-SD-NEXT:    bif v1.16b, v3.16b, v4.16b
+; CHECK-SD-NEXT:    ret
----------------
arsenm wrote:

DAG looks better? 

https://github.com/llvm/llvm-project/pull/71283