[AArch64] Fix SVE scalar fcopysign lowering without neon. (llvm#129787)

Without this we can try to generate invalid instructions or create
illegal types. This patch generates a SVE fcopysign instead and use its
lowering. BF16 is left out of the moment as it doesn't lower
successfully (but could use the same code as fp16).

(cherry picked from commit d4ab3df)

Author: davemgreen

llvm/lib/Target/AArch64/AArch64ISelLowering.cpp

@@ -10683,6 +10683,25 @@ SDValue AArch64TargetLowering::LowerFCOPYSIGN(SDValue Op,
     return convertFromScalableVector(DAG, VT, Res);
   }
 
+  // With SVE, but without Neon, extend the scalars to scalable vectors and use
+  // a SVE FCOPYSIGN.
+  if (!VT.isVector() && !Subtarget->isNeonAvailable() &&
+      Subtarget->isSVEorStreamingSVEAvailable()) {
+    if (VT != MVT::f16 && VT != MVT::f32 && VT != MVT::f64)
+      return SDValue();
+    EVT SVT = getPackedSVEVectorVT(VT);
+
+    SDValue Ins1 =
+        DAG.getNode(ISD::INSERT_VECTOR_ELT, DL, SVT, DAG.getUNDEF(SVT), In1,
+                    DAG.getConstant(0, DL, MVT::i64));
+    SDValue Ins2 =
+        DAG.getNode(ISD::INSERT_VECTOR_ELT, DL, SVT, DAG.getUNDEF(SVT), In2,
+                    DAG.getConstant(0, DL, MVT::i64));
+    SDValue FCS = DAG.getNode(ISD::FCOPYSIGN, DL, SVT, Ins1, Ins2);
+    return DAG.getNode(ISD::EXTRACT_VECTOR_ELT, DL, VT, FCS,
+                       DAG.getConstant(0, DL, MVT::i64));
+  }
+
   auto BitCast = [this](EVT VT, SDValue Op, SelectionDAG &DAG) {
     if (VT.isScalableVector())
       return getSVESafeBitCast(VT, Op, DAG);

llvm/test/CodeGen/AArch64/sve-streaming-mode-fixed-length-fcopysign.ll

@@ -11,32 +11,21 @@ target triple = "aarch64-unknown-linux-gnu"
 define void @test_copysign_f16(ptr %ap, ptr %bp) {
 ; SVE-LABEL: test_copysign_f16:
 ; SVE:       // %bb.0:
-; SVE-NEXT:    adrp x8, .LCPI0_0
+; SVE-NEXT:    ldr h0, [x1]
 ; SVE-NEXT:    ldr h1, [x0]
-; SVE-NEXT:    ldr h2, [x1]
-; SVE-NEXT:    ldr q0, [x8, :lo12:.LCPI0_0]
-; SVE-NEXT:    adrp x8, .LCPI0_1
-; SVE-NEXT:    ldr q4, [x8, :lo12:.LCPI0_1]
-; SVE-NEXT:    mov z3.d, z0.d
-; SVE-NEXT:    fmov s0, s1
-; SVE-NEXT:    fmov s3, s2
-; SVE-NEXT:    bif v0.16b, v3.16b, v4.16b
+; SVE-NEXT:    and z0.h, z0.h, #0x8000
+; SVE-NEXT:    and z1.h, z1.h, #0x7fff
+; SVE-NEXT:    orr z0.d, z1.d, z0.d
 ; SVE-NEXT:    str h0, [x0]
 ; SVE-NEXT:    ret
 ;
 ; SVE2-LABEL: test_copysign_f16:
 ; SVE2:       // %bb.0:
-; SVE2-NEXT:    adrp x8, .LCPI0_0
-; SVE2-NEXT:    ldr h1, [x0]
-; SVE2-NEXT:    ldr h2, [x1]
-; SVE2-NEXT:    ldr q0, [x8, :lo12:.LCPI0_0]
-; SVE2-NEXT:    adrp x8, .LCPI0_1
-; SVE2-NEXT:    ldr q4, [x8, :lo12:.LCPI0_1]
-; SVE2-NEXT:    mov z3.d, z0.d
-; SVE2-NEXT:    fmov s0, s1
-; SVE2-NEXT:    fmov s3, s2
-; SVE2-NEXT:    bif v0.16b, v3.16b, v4.16b
-; SVE2-NEXT:    str h0, [x0]
+; SVE2-NEXT:    mov z0.h, #32767 // =0x7fff
+; SVE2-NEXT:    ldr h1, [x1]
+; SVE2-NEXT:    ldr h2, [x0]
+; SVE2-NEXT:    bsl z2.d, z2.d, z1.d, z0.d
+; SVE2-NEXT:    str h2, [x0]
 ; SVE2-NEXT:    ret
 ;
 ; NONEON-NOSVE-LABEL: test_copysign_f16:
@@ -66,32 +55,40 @@ define void @test_copysign_f16(ptr %ap, ptr %bp) {
 define void @test_copysign_bf16(ptr %ap, ptr %bp) {
 ; SVE-LABEL: test_copysign_bf16:
 ; SVE:       // %bb.0:
-; SVE-NEXT:    adrp x8, .LCPI1_0
-; SVE-NEXT:    ldr h1, [x0]
-; SVE-NEXT:    ldr h2, [x1]
-; SVE-NEXT:    ldr q0, [x8, :lo12:.LCPI1_0]
-; SVE-NEXT:    adrp x8, .LCPI1_1
-; SVE-NEXT:    ldr q4, [x8, :lo12:.LCPI1_1]
-; SVE-NEXT:    mov z3.d, z0.d
-; SVE-NEXT:    fmov s0, s1
-; SVE-NEXT:    fmov s3, s2
-; SVE-NEXT:    bif v0.16b, v3.16b, v4.16b
+; SVE-NEXT:    sub sp, sp, #16
+; SVE-NEXT:    .cfi_def_cfa_offset 16
+; SVE-NEXT:    ldr h0, [x0]
+; SVE-NEXT:    ldr h1, [x1]
+; SVE-NEXT:    fmov w8, s0
+; SVE-NEXT:    str h1, [sp, #12]
+; SVE-NEXT:    ldrb w9, [sp, #13]
+; SVE-NEXT:    and w8, w8, #0x7fff
+; SVE-NEXT:    tst w9, #0x80
+; SVE-NEXT:    fmov s0, w8
+; SVE-NEXT:    eor w8, w8, #0x8000
+; SVE-NEXT:    fmov s1, w8
+; SVE-NEXT:    fcsel h0, h1, h0, ne
 ; SVE-NEXT:    str h0, [x0]
+; SVE-NEXT:    add sp, sp, #16
 ; SVE-NEXT:    ret
 ;
 ; SVE2-LABEL: test_copysign_bf16:
 ; SVE2:       // %bb.0:
-; SVE2-NEXT:    adrp x8, .LCPI1_0
-; SVE2-NEXT:    ldr h1, [x0]
-; SVE2-NEXT:    ldr h2, [x1]
-; SVE2-NEXT:    ldr q0, [x8, :lo12:.LCPI1_0]
-; SVE2-NEXT:    adrp x8, .LCPI1_1
-; SVE2-NEXT:    ldr q4, [x8, :lo12:.LCPI1_1]
-; SVE2-NEXT:    mov z3.d, z0.d
-; SVE2-NEXT:    fmov s0, s1
-; SVE2-NEXT:    fmov s3, s2
-; SVE2-NEXT:    bif v0.16b, v3.16b, v4.16b
+; SVE2-NEXT:    sub sp, sp, #16
+; SVE2-NEXT:    .cfi_def_cfa_offset 16
+; SVE2-NEXT:    ldr h0, [x0]
+; SVE2-NEXT:    ldr h1, [x1]
+; SVE2-NEXT:    fmov w8, s0
+; SVE2-NEXT:    str h1, [sp, #12]
+; SVE2-NEXT:    ldrb w9, [sp, #13]
+; SVE2-NEXT:    and w8, w8, #0x7fff
+; SVE2-NEXT:    tst w9, #0x80
+; SVE2-NEXT:    fmov s0, w8
+; SVE2-NEXT:    eor w8, w8, #0x8000
+; SVE2-NEXT:    fmov s1, w8
+; SVE2-NEXT:    fcsel h0, h1, h0, ne
 ; SVE2-NEXT:    str h0, [x0]
+; SVE2-NEXT:    add sp, sp, #16
 ; SVE2-NEXT:    ret
 ;
 ; NONEON-NOSVE-LABEL: test_copysign_bf16:
@@ -139,32 +136,21 @@ define void @test_copysign_bf16(ptr %ap, ptr %bp) {
 define void @test_copysign_f32(ptr %ap, ptr %bp) {
 ; SVE-LABEL: test_copysign_f32:
 ; SVE:       // %bb.0:
-; SVE-NEXT:    adrp x8, .LCPI2_0
+; SVE-NEXT:    ldr s0, [x1]
 ; SVE-NEXT:    ldr s1, [x0]
-; SVE-NEXT:    ldr s2, [x1]
-; SVE-NEXT:    ldr q0, [x8, :lo12:.LCPI2_0]
-; SVE-NEXT:    adrp x8, .LCPI2_1
-; SVE-NEXT:    ldr q4, [x8, :lo12:.LCPI2_1]
-; SVE-NEXT:    mov z3.d, z0.d
-; SVE-NEXT:    fmov s0, s1
-; SVE-NEXT:    fmov s3, s2
-; SVE-NEXT:    bif v0.16b, v3.16b, v4.16b
+; SVE-NEXT:    and z0.s, z0.s, #0x80000000
+; SVE-NEXT:    and z1.s, z1.s, #0x7fffffff
+; SVE-NEXT:    orr z0.d, z1.d, z0.d
 ; SVE-NEXT:    str s0, [x0]
 ; SVE-NEXT:    ret
 ;
 ; SVE2-LABEL: test_copysign_f32:
 ; SVE2:       // %bb.0:
-; SVE2-NEXT:    adrp x8, .LCPI2_0
-; SVE2-NEXT:    ldr s1, [x0]
-; SVE2-NEXT:    ldr s2, [x1]
-; SVE2-NEXT:    ldr q0, [x8, :lo12:.LCPI2_0]
-; SVE2-NEXT:    adrp x8, .LCPI2_1
-; SVE2-NEXT:    ldr q4, [x8, :lo12:.LCPI2_1]
-; SVE2-NEXT:    mov z3.d, z0.d
-; SVE2-NEXT:    fmov s0, s1
-; SVE2-NEXT:    fmov s3, s2
-; SVE2-NEXT:    bif v0.16b, v3.16b, v4.16b
-; SVE2-NEXT:    str s0, [x0]
+; SVE2-NEXT:    mov z0.s, #0x7fffffff
+; SVE2-NEXT:    ldr s1, [x1]
+; SVE2-NEXT:    ldr s2, [x0]
+; SVE2-NEXT:    bsl z2.d, z2.d, z1.d, z0.d
+; SVE2-NEXT:    str s2, [x0]
 ; SVE2-NEXT:    ret
 ;
 ; NONEON-NOSVE-LABEL: test_copysign_f32:
@@ -187,36 +173,21 @@ define void @test_copysign_f32(ptr %ap, ptr %bp) {
 define void @test_copysign_f64(ptr %ap, ptr %bp) {
 ; SVE-LABEL: test_copysign_f64:
 ; SVE:       // %bb.0:
-; SVE-NEXT:    adrp x8, .LCPI3_1
-; SVE-NEXT:    ptrue p0.d, vl2
-; SVE-NEXT:    ldr d2, [x0]
-; SVE-NEXT:    ldr q0, [x8, :lo12:.LCPI3_1]
-; SVE-NEXT:    adrp x8, .LCPI3_0
-; SVE-NEXT:    ldr d3, [x1]
-; SVE-NEXT:    ldr q1, [x8, :lo12:.LCPI3_0]
-; SVE-NEXT:    fneg z0.d, p0/m, z0.d
-; SVE-NEXT:    mov z4.d, z1.d
-; SVE-NEXT:    fmov d1, d2
-; SVE-NEXT:    fmov d4, d3
-; SVE-NEXT:    bsl v0.16b, v1.16b, v4.16b
+; SVE-NEXT:    ldr d0, [x1]
+; SVE-NEXT:    ldr d1, [x0]
+; SVE-NEXT:    and z0.d, z0.d, #0x8000000000000000
+; SVE-NEXT:    and z1.d, z1.d, #0x7fffffffffffffff
+; SVE-NEXT:    orr z0.d, z1.d, z0.d
 ; SVE-NEXT:    str d0, [x0]
 ; SVE-NEXT:    ret
 ;
 ; SVE2-LABEL: test_copysign_f64:
 ; SVE2:       // %bb.0:
-; SVE2-NEXT:    adrp x8, .LCPI3_1
-; SVE2-NEXT:    ptrue p0.d, vl2
+; SVE2-NEXT:    mov z0.d, #0x7fffffffffffffff
+; SVE2-NEXT:    ldr d1, [x1]
 ; SVE2-NEXT:    ldr d2, [x0]
-; SVE2-NEXT:    ldr q0, [x8, :lo12:.LCPI3_1]
-; SVE2-NEXT:    adrp x8, .LCPI3_0
-; SVE2-NEXT:    ldr d3, [x1]
-; SVE2-NEXT:    ldr q1, [x8, :lo12:.LCPI3_0]
-; SVE2-NEXT:    fneg z0.d, p0/m, z0.d
-; SVE2-NEXT:    mov z4.d, z1.d
-; SVE2-NEXT:    fmov d1, d2
-; SVE2-NEXT:    fmov d4, d3
-; SVE2-NEXT:    bsl v0.16b, v1.16b, v4.16b
-; SVE2-NEXT:    str d0, [x0]
+; SVE2-NEXT:    bsl z2.d, z2.d, z1.d, z0.d
+; SVE2-NEXT:    str d2, [x0]
 ; SVE2-NEXT:    ret
 ;
 ; NONEON-NOSVE-LABEL: test_copysign_f64: