[AArch64] Add a tablegen pattern for UZP2.

Converts concat_vectors((trunc (lshr)), (trunc (lshr))) to UZP2
when the shift amount is half the width of the vector element.

Differential Revision: https://reviews.llvm.org/D116021

diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.td b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
index 3f174bb..727e160 100644 (file)
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
@@ -5316,6 +5316,19 @@ def : Pat<(v4i32 (concat_vectors (v2i32 (trunc (v2i64 V128:$Vn))),
                                  (v2i32 (trunc (v2i64 V128:$Vm))))),
           (UZP1v4i32 V128:$Vn, V128:$Vm)>;
 
+def : Pat<(v16i8 (concat_vectors
+                 (v8i8 (trunc (AArch64vlshr (v8i16 V128:$Vn), (i32 8)))),
+                 (v8i8 (trunc (AArch64vlshr (v8i16 V128:$Vm), (i32 8)))))),
+          (UZP2v16i8 V128:$Vn, V128:$Vm)>;
+def : Pat<(v8i16 (concat_vectors
+                 (v4i16 (trunc (AArch64vlshr (v4i32 V128:$Vn), (i32 16)))),
+                 (v4i16 (trunc (AArch64vlshr (v4i32 V128:$Vm), (i32 16)))))),
+          (UZP2v8i16 V128:$Vn, V128:$Vm)>;
+def : Pat<(v4i32 (concat_vectors
+                 (v2i32 (trunc (AArch64vlshr (v2i64 V128:$Vn), (i32 32)))),
+                 (v2i32 (trunc (AArch64vlshr (v2i64 V128:$Vm), (i32 32)))))),
+          (UZP2v4i32 V128:$Vn, V128:$Vm)>;
+
 //----------------------------------------------------------------------------
 // AdvSIMD TBL/TBX instructions
 //----------------------------------------------------------------------------

diff --git a/llvm/test/CodeGen/AArch64/arm64-uzp2-combine.ll b/llvm/test/CodeGen/AArch64/arm64-uzp2-combine.ll
new file mode 100644 (file)
index 0000000..e3c52e6
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/arm64-uzp2-combine.ll
@@ -0,0 +1,47 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc < %s -mtriple aarch64-none-linux-gnu | FileCheck %s
+
+; Test the (concat_vectors (trunc (lshr)), (trunc (lshr))) pattern.
+
+define <16 x i8> @test_combine_v8i16_to_v16i8(<8 x i16> %x, <8 x i16> %y) {
+; CHECK-LABEL: test_combine_v8i16_to_v16i8:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    uzp2 v0.16b, v0.16b, v1.16b
+; CHECK-NEXT:    ret
+entry:
+  %lshr1 = lshr <8 x i16> %x, <i16 8, i16 8, i16 8, i16 8, i16 8, i16 8, i16 8, i16 8>
+  %trunc1 = trunc <8 x i16> %lshr1 to <8 x i8>
+  %lshr2 = lshr <8 x i16> %y, <i16 8, i16 8, i16 8, i16 8, i16 8, i16 8, i16 8, i16 8>
+  %trunc2 = trunc <8 x i16> %lshr2 to <8 x i8>
+  %shuffle = shufflevector <8 x i8> %trunc1, <8 x i8> %trunc2, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
+  ret <16 x i8> %shuffle
+}
+
+define <8 x i16> @test_combine_v4i32_to_v8i16(<4 x i32> %x, <4 x i32> %y) {
+; CHECK-LABEL: test_combine_v4i32_to_v8i16:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    uzp2 v0.8h, v0.8h, v1.8h
+; CHECK-NEXT:    ret
+entry:
+  %lshr1 = lshr <4 x i32> %x, <i32 16, i32 16, i32 16, i32 16>
+  %trunc1 = trunc <4 x i32> %lshr1 to <4 x i16>
+  %lshr2 = lshr <4 x i32> %y, <i32 16, i32 16, i32 16, i32 16>
+  %trunc2 = trunc <4 x i32> %lshr2 to <4 x i16>
+  %shuffle = shufflevector <4 x i16> %trunc1, <4 x i16> %trunc2, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
+  ret <8 x i16> %shuffle
+}
+
+define <4 x i32> @test_combine_v2i64_to_v4i32(<2 x i64> %x, <2 x i64> %y) {
+; CHECK-LABEL: test_combine_v2i64_to_v4i32:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    uzp2 v0.4s, v0.4s, v1.4s
+; CHECK-NEXT:    ret
+entry:
+  %lshr1 = lshr <2 x i64> %x, <i64 32, i64 32>
+  %trunc1 = trunc <2 x i64> %lshr1 to <2 x i32>
+  %lshr2 = lshr <2 x i64> %y, <i64 32, i64 32>
+  %trunc2 = trunc <2 x i64> %lshr2 to <2 x i32>
+  %shuffle = shufflevector <2 x i32> %trunc1, <2 x i32> %trunc2, <4 x i32> <i32 0, i32 1, i32 2, i32 3>
+  ret <4 x i32> %shuffle
+}
+