[llvm] intrinsic to generate a bfi instruction (PR #79655)

[Rama Malladi via llvm-commits]

https://github.com/RamaMalladiAWS created https://github.com/llvm/llvm-project/pull/79655

None

>From 96aba7076392fb7f7479ec3a313ced5cfb714f81 Mon Sep 17 00:00:00 2001
From: Ubuntu <ubuntu at ip-172-31-45-128.ec2.internal>
Date: Fri, 26 Jan 2024 18:56:32 +0000
Subject: [PATCH] intrinsic to generate a bfi instruction

---
 llvm/include/llvm/IR/IntrinsicsAArch64.td     |  3 +++
 .../Target/AArch64/AArch64ISelDAGToDAG.cpp    | 13 ++++++++++++
 llvm/lib/Target/AArch64/AArch64InstrInfo.td   |  8 ++++++++
 llvm/test/CodeGen/AArch64/bfi-64-intrinsic.ll | 20 +++++++++++++++++++
 4 files changed, 44 insertions(+)
 create mode 100644 llvm/test/CodeGen/AArch64/bfi-64-intrinsic.ll

diff --git a/llvm/include/llvm/IR/IntrinsicsAArch64.td b/llvm/include/llvm/IR/IntrinsicsAArch64.td
index 921e5b95ae03e8d..9eb5154c95138f9 100644
--- a/llvm/include/llvm/IR/IntrinsicsAArch64.td
+++ b/llvm/include/llvm/IR/IntrinsicsAArch64.td
@@ -855,6 +855,9 @@ def int_aarch64_crc32x  : DefaultAttrsIntrinsic<[llvm_i32_ty], [llvm_i32_ty, llv
     [IntrNoMem]>;
 def int_aarch64_crc32cx : DefaultAttrsIntrinsic<[llvm_i32_ty], [llvm_i32_ty, llvm_i64_ty],
     [IntrNoMem]>;
+def int_aarch64_bfi : DefaultAttrsIntrinsic<
+    [llvm_anyint_ty], [llvm_anyint_ty, llvm_anyint_ty, llvm_anyint_ty, llvm_anyint_ty],
+    [IntrNoMem, ImmArg<ArgIndex<2>>, ImmArg<ArgIndex<3>>]>;
 }
 
 //===----------------------------------------------------------------------===//
diff --git a/llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp b/llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp
index 163ed520a8a677b..1fe3f95d54d1319 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp
@@ -5230,6 +5230,19 @@ void AArch64DAGToDAGISel::Select(SDNode *Node) {
     switch (IntNo) {
     default:
       break;
+    case Intrinsic::aarch64_bfi: {
+      SDLoc DL(Node);
+      auto lsb = cast<ConstantSDNode>(Node->getOperand(3))->getZExtValue();
+      auto width = cast<ConstantSDNode>(Node->getOperand(4))->getZExtValue();
+      auto ImmR = (VT.getSizeInBits() - lsb) % VT.getSizeInBits();
+      auto ImmS = width - 1;
+      SDValue Ops[] = {Node->getOperand(1), Node->getOperand(2),
+                       CurDAG->getConstant(ImmR, DL, VT),
+                       CurDAG->getConstant(ImmS, DL, VT)};
+      unsigned Opc = (VT == MVT::i32) ? AArch64::BFMWri : AArch64::BFMXri;
+      CurDAG->SelectNodeTo(Node, Opc, VT, Ops);
+      return;
+    }
     case Intrinsic::aarch64_tagp:
       SelectTagP(Node);
       return;
diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.td b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
index 03baa7497615e3d..afa911abad79824 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
@@ -2558,6 +2558,14 @@ def : Pat<(rotr GPR32:$Rn, (i64 imm0_31:$imm)),
 def : Pat<(rotr GPR64:$Rn, (i64 imm0_63:$imm)),
           (EXTRXrri GPR64:$Rn, GPR64:$Rn, imm0_63:$imm)>;
 
+def SDT_AArch64BFI_32bit : SDTypeProfile<1, 2, [SDTCisVT<0, i32>, SDTCisVT<1, i32>,
+                                                    SDTCisVT<2, i32>]>;
+def SDT_AArch64BFI_64bit : SDTypeProfile<1, 2, [SDTCisVT<0, i64>, SDTCisVT<1, i64>,
+                                                    SDTCisVT<2, i64>]>;
+
+def aarch64_bfiw  : SDNode<"AArch64::BFMWri",  SDT_AArch64BFI_32bit>;
+def aarch64_bfix  : SDNode<"AArch64::BFMXri",  SDT_AArch64BFI_64bit>;
+
 //===----------------------------------------------------------------------===//
 // Other bitfield immediate instructions.
 //===----------------------------------------------------------------------===//
diff --git a/llvm/test/CodeGen/AArch64/bfi-64-intrinsic.ll b/llvm/test/CodeGen/AArch64/bfi-64-intrinsic.ll
new file mode 100644
index 000000000000000..99b23fb1101d6c8
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/bfi-64-intrinsic.ll
@@ -0,0 +1,20 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=aarch64-none-linux-gnu < %s -o -| FileCheck %s
+
+define i32 @f32(i32 %A, i32 %B) nounwind {
+; CHECK-NEXT:    bfi r0, r1, #4, #2
+entry:
+  %tmp32 = call i32 @llvm.aarch64.bfi.i32(i32 %A, i32 %B, i32 4, i32 2)
+  ret i32 %tmp32
+}
+
+define i64 @f64(i64 %A, i64 %B) nounwind {
+; CHECK-NEXT:    bfi r0, r1, #23, #8
+entry:
+  %tmp64 = call i64 @llvm.aarch64.bfi.i64(i64 %A, i64 %B, i64 23, i64 8)
+  ret i64 %tmp64
+}
+
+declare i32 @llvm.aarch64.bfi.i32(i32, i32, i32, i32)
+declare i64 @llvm.aarch64.bfi.i64(i64, i64, i64, i64)
+