[llvm] [AArch64] Don't generate neon integer complex numbers with +sve2. NFC (PR #79829)

[David Green via llvm-commits]

https://github.com/davemgreen created https://github.com/llvm/llvm-project/pull/79829

The condition for allowing integer complex number support could also allow neon fixed length complex numbers if +sve2 was specified. This tightens the condition to only allow integer complex number support for scalable vectors.

We could generalize this in the future to generate SVE intrinsics for fixed-length vectors, but for the moment this opts for the simpler fix.

>From c34752dfee453d15e49f7f69ab0fc09f478fea24 Mon Sep 17 00:00:00 2001
From: David Green <david.green at arm.com>
Date: Mon, 29 Jan 2024 13:51:00 +0000
Subject: [PATCH] [AArch64] Don't generate neon integer complex numbers with
 +sve2. NFC

The condition for allowing integer complex number support could also allow neon
fixed length complex numbers if +sve2 was specified. This tightens the
condition to only allow integer complex number support for scalable vectors.

We could generalize this in the future to generate SVE intrinsics for
fixed-length vectors, but for the moment this opts for the simpler fix.
---
 .../Target/AArch64/AArch64ISelLowering.cpp    |  4 +--
 .../AArch64/complex-deinterleaving-f16-add.ll | 27 +++++++++++++++++++
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
index 2cb7770ee21e4f..5bb8aabea80dbb 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -26949,7 +26949,7 @@ bool AArch64TargetLowering::isComplexDeinterleavingOperationSupported(
     return false;
 
   // If the vector is scalable, SVE is enabled, implying support for complex
-  // numbers. Otherwirse, we need to ensure complex number support is avaialble
+  // numbers. Otherwise, we need to ensure complex number support is available
   if (!VTy->isScalableTy() && !Subtarget->hasComplxNum())
     return false;
 
@@ -26965,7 +26965,7 @@ bool AArch64TargetLowering::isComplexDeinterleavingOperationSupported(
       !llvm::isPowerOf2_32(VTyWidth))
     return false;
 
-  if (ScalarTy->isIntegerTy() && Subtarget->hasSVE2()) {
+  if (ScalarTy->isIntegerTy() && Subtarget->hasSVE2() && VTy->isScalableTy()) {
     unsigned ScalarWidth = ScalarTy->getScalarSizeInBits();
     return 8 <= ScalarWidth && ScalarWidth <= 64;
   }
diff --git a/llvm/test/CodeGen/AArch64/complex-deinterleaving-f16-add.ll b/llvm/test/CodeGen/AArch64/complex-deinterleaving-f16-add.ll
index 93497f38063d28..7b8448de2331b4 100644
--- a/llvm/test/CodeGen/AArch64/complex-deinterleaving-f16-add.ll
+++ b/llvm/test/CodeGen/AArch64/complex-deinterleaving-f16-add.ll
@@ -1,6 +1,7 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
 ; RUN: llc < %s --mattr=+complxnum,+neon,+fullfp16 -o - | FileCheck %s
 ; RUN: llc < %s --mattr=+complxnum,+neon,+fullfp16,+sve -o - | FileCheck %s
+; RUN: llc < %s --mattr=+complxnum,+neon,+fullfp16,+sve2 -o - | FileCheck %s
 
 target triple = "aarch64"
 
@@ -158,6 +159,32 @@ entry:
   ret <16 x half> %interleaved.vec
 }
 
+
+; Expected not to transform as it is integer
+define <16 x i16> @complex_add_v16i16(<16 x i16> %a, <16 x i16> %b) {
+; CHECK-LABEL: complex_add_v16i16:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    uzp1 v4.8h, v2.8h, v3.8h
+; CHECK-NEXT:    uzp1 v5.8h, v0.8h, v1.8h
+; CHECK-NEXT:    uzp2 v0.8h, v0.8h, v1.8h
+; CHECK-NEXT:    uzp2 v1.8h, v2.8h, v3.8h
+; CHECK-NEXT:    sub v2.8h, v4.8h, v0.8h
+; CHECK-NEXT:    add v1.8h, v1.8h, v5.8h
+; CHECK-NEXT:    zip1 v0.8h, v2.8h, v1.8h
+; CHECK-NEXT:    zip2 v1.8h, v2.8h, v1.8h
+; CHECK-NEXT:    ret
+entry:
+  %a.real = shufflevector <16 x i16> %a, <16 x i16> zeroinitializer, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 8, i32 10, i32 12, i32 14>
+  %a.imag = shufflevector <16 x i16> %a, <16 x i16> zeroinitializer, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 9, i32 11, i32 13, i32 15>
+  %b.real = shufflevector <16 x i16> %b, <16 x i16> zeroinitializer, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 8, i32 10, i32 12, i32 14>
+  %b.imag = shufflevector <16 x i16> %b, <16 x i16> zeroinitializer, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 9, i32 11, i32 13, i32 15>
+  %0 = sub <8 x i16> %b.real, %a.imag
+  %1 = add <8 x i16> %b.imag, %a.real
+  %interleaved.vec = shufflevector <8 x i16> %0, <8 x i16> %1, <16 x i32> <i32 0, i32 8, i32 1, i32 9, i32 2, i32 10, i32 3, i32 11, i32 4, i32 12, i32 5, i32 13, i32 6, i32 14, i32 7, i32 15>
+  ret <16 x i16> %interleaved.vec
+}
+
+
 declare { <2 x half>, <2 x half> } @llvm.experimental.vector.deinterleave2.v4f16(<4 x half>)
 declare <4 x half> @llvm.experimental.vector.interleave2.v4f16(<2 x half>, <2 x half>)