[AArch64][GlobalISel] Lower Shuffle Vector to REV (#79591)

Add lowering for i16 and i32 vectors for Shuffle Vector instructions
with REV mask

Author: ChuongGoh-arm

llvm/lib/Target/AArch64/GISel/AArch64PostLegalizerLowering.cpp

@@ -242,15 +242,22 @@ bool matchREV(MachineInstr &MI, MachineRegisterInfo &MRI,
 
   unsigned NumElts = Ty.getNumElements();
 
-  // Try to produce G_REV64
-  if (isREVMask(ShuffleMask, EltSize, NumElts, 64)) {
-    MatchInfo = ShuffleVectorPseudo(AArch64::G_REV64, Dst, {Src});
-    return true;
+  // Try to produce a G_REV instruction
+  for (unsigned LaneSize : {64U, 32U, 16U}) {
+    if (isREVMask(ShuffleMask, EltSize, NumElts, LaneSize)) {
+      unsigned Opcode;
+      if (LaneSize == 64U)
+        Opcode = AArch64::G_REV64;
+      else if (LaneSize == 32U)
+        Opcode = AArch64::G_REV32;
+      else
+        Opcode = AArch64::G_REV16;
+
+      MatchInfo = ShuffleVectorPseudo(Opcode, Dst, {Src});
+      return true;
+    }
   }
 
-  // TODO: Produce G_REV32 and G_REV16 once we have proper legalization support.
-  // This should be identical to above, but with a constant 32 and constant
-  // 16.
   return false;
 }
 

llvm/test/CodeGen/AArch64/arm64-rev.ll

@@ -296,120 +296,66 @@ define <4 x float> @test_vrev64Qf(ptr %A) nounwind {
 }
 
 define <8 x i8> @test_vrev32D8(ptr %A) nounwind {
-; CHECK-SD-LABEL: test_vrev32D8:
-; CHECK-SD:       // %bb.0:
-; CHECK-SD-NEXT:    ldr d0, [x0]
-; CHECK-SD-NEXT:    rev32.8b v0, v0
-; CHECK-SD-NEXT:    ret
-;
-; CHECK-GI-LABEL: test_vrev32D8:
-; CHECK-GI:       // %bb.0:
-; CHECK-GI-NEXT:    ldr d0, [x0]
-; CHECK-GI-NEXT:    adrp x8, .LCPI19_0
-; CHECK-GI-NEXT:    ldr d1, [x8, :lo12:.LCPI19_0]
-; CHECK-GI-NEXT:    mov.d v0[1], v0[0]
-; CHECK-GI-NEXT:    tbl.16b v0, { v0 }, v1
-; CHECK-GI-NEXT:    // kill: def $d0 killed $d0 killed $q0
-; CHECK-GI-NEXT:    ret
+; CHECK-LABEL: test_vrev32D8:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ldr d0, [x0]
+; CHECK-NEXT:    rev32.8b v0, v0
+; CHECK-NEXT:    ret
 	%tmp1 = load <8 x i8>, ptr %A
 	%tmp2 = shufflevector <8 x i8> %tmp1, <8 x i8> undef, <8 x i32> <i32 3, i32 2, i32 1, i32 0, i32 7, i32 6, i32 5, i32 4>
 	ret <8 x i8> %tmp2
 }
 
 define <4 x i16> @test_vrev32D16(ptr %A) nounwind {
-; CHECK-SD-LABEL: test_vrev32D16:
-; CHECK-SD:       // %bb.0:
-; CHECK-SD-NEXT:    ldr d0, [x0]
-; CHECK-SD-NEXT:    rev32.4h v0, v0
-; CHECK-SD-NEXT:    ret
-;
-; CHECK-GI-LABEL: test_vrev32D16:
-; CHECK-GI:       // %bb.0:
-; CHECK-GI-NEXT:    ldr d0, [x0]
-; CHECK-GI-NEXT:    adrp x8, .LCPI20_0
-; CHECK-GI-NEXT:    ldr d1, [x8, :lo12:.LCPI20_0]
-; CHECK-GI-NEXT:    mov.d v0[1], v0[0]
-; CHECK-GI-NEXT:    tbl.16b v0, { v0 }, v1
-; CHECK-GI-NEXT:    // kill: def $d0 killed $d0 killed $q0
-; CHECK-GI-NEXT:    ret
+; CHECK-LABEL: test_vrev32D16:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ldr d0, [x0]
+; CHECK-NEXT:    rev32.4h v0, v0
+; CHECK-NEXT:    ret
 	%tmp1 = load <4 x i16>, ptr %A
 	%tmp2 = shufflevector <4 x i16> %tmp1, <4 x i16> undef, <4 x i32> <i32 1, i32 0, i32 3, i32 2>
 	ret <4 x i16> %tmp2
 }
 
 define <16 x i8> @test_vrev32Q8(ptr %A) nounwind {
-; CHECK-SD-LABEL: test_vrev32Q8:
-; CHECK-SD:       // %bb.0:
-; CHECK-SD-NEXT:    ldr q0, [x0]
-; CHECK-SD-NEXT:    rev32.16b v0, v0
-; CHECK-SD-NEXT:    ret
-;
-; CHECK-GI-LABEL: test_vrev32Q8:
-; CHECK-GI:       // %bb.0:
-; CHECK-GI-NEXT:    adrp x8, .LCPI21_0
-; CHECK-GI-NEXT:    ldr q0, [x0]
-; CHECK-GI-NEXT:    ldr q2, [x8, :lo12:.LCPI21_0]
-; CHECK-GI-NEXT:    tbl.16b v0, { v0, v1 }, v2
-; CHECK-GI-NEXT:    ret
+; CHECK-LABEL: test_vrev32Q8:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ldr q0, [x0]
+; CHECK-NEXT:    rev32.16b v0, v0
+; CHECK-NEXT:    ret
 	%tmp1 = load <16 x i8>, ptr %A
 	%tmp2 = shufflevector <16 x i8> %tmp1, <16 x i8> undef, <16 x i32> <i32 3, i32 2, i32 1, i32 0, i32 7, i32 6, i32 5, i32 4, i32 11, i32 10, i32 9, i32 8, i32 15, i32 14, i32 13, i32 12>
 	ret <16 x i8> %tmp2
 }
 
 define <8 x i16> @test_vrev32Q16(ptr %A) nounwind {
-; CHECK-SD-LABEL: test_vrev32Q16:
-; CHECK-SD:       // %bb.0:
-; CHECK-SD-NEXT:    ldr q0, [x0]
-; CHECK-SD-NEXT:    rev32.8h v0, v0
-; CHECK-SD-NEXT:    ret
-;
-; CHECK-GI-LABEL: test_vrev32Q16:
-; CHECK-GI:       // %bb.0:
-; CHECK-GI-NEXT:    adrp x8, .LCPI22_0
-; CHECK-GI-NEXT:    ldr q0, [x0]
-; CHECK-GI-NEXT:    ldr q2, [x8, :lo12:.LCPI22_0]
-; CHECK-GI-NEXT:    tbl.16b v0, { v0, v1 }, v2
-; CHECK-GI-NEXT:    ret
+; CHECK-LABEL: test_vrev32Q16:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ldr q0, [x0]
+; CHECK-NEXT:    rev32.8h v0, v0
+; CHECK-NEXT:    ret
 	%tmp1 = load <8 x i16>, ptr %A
 	%tmp2 = shufflevector <8 x i16> %tmp1, <8 x i16> undef, <8 x i32> <i32 1, i32 0, i32 3, i32 2, i32 5, i32 4, i32 7, i32 6>
 	ret <8 x i16> %tmp2
 }
 
 define <8 x i8> @test_vrev16D8(ptr %A) nounwind {
-; CHECK-SD-LABEL: test_vrev16D8:
-; CHECK-SD:       // %bb.0:
-; CHECK-SD-NEXT:    ldr d0, [x0]
-; CHECK-SD-NEXT:    rev16.8b v0, v0
-; CHECK-SD-NEXT:    ret
-;
-; CHECK-GI-LABEL: test_vrev16D8:
-; CHECK-GI:       // %bb.0:
-; CHECK-GI-NEXT:    ldr d0, [x0]
-; CHECK-GI-NEXT:    adrp x8, .LCPI23_0
-; CHECK-GI-NEXT:    ldr d1, [x8, :lo12:.LCPI23_0]
-; CHECK-GI-NEXT:    mov.d v0[1], v0[0]
-; CHECK-GI-NEXT:    tbl.16b v0, { v0 }, v1
-; CHECK-GI-NEXT:    // kill: def $d0 killed $d0 killed $q0
-; CHECK-GI-NEXT:    ret
+; CHECK-LABEL: test_vrev16D8:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ldr d0, [x0]
+; CHECK-NEXT:    rev16.8b v0, v0
+; CHECK-NEXT:    ret
 	%tmp1 = load <8 x i8>, ptr %A
 	%tmp2 = shufflevector <8 x i8> %tmp1, <8 x i8> undef, <8 x i32> <i32 1, i32 0, i32 3, i32 2, i32 5, i32 4, i32 7, i32 6>
 	ret <8 x i8> %tmp2
 }
 
 define <16 x i8> @test_vrev16Q8(ptr %A) nounwind {
-; CHECK-SD-LABEL: test_vrev16Q8:
-; CHECK-SD:       // %bb.0:
-; CHECK-SD-NEXT:    ldr q0, [x0]
-; CHECK-SD-NEXT:    rev16.16b v0, v0
-; CHECK-SD-NEXT:    ret
-;
-; CHECK-GI-LABEL: test_vrev16Q8:
-; CHECK-GI:       // %bb.0:
-; CHECK-GI-NEXT:    adrp x8, .LCPI24_0
-; CHECK-GI-NEXT:    ldr q0, [x0]
-; CHECK-GI-NEXT:    ldr q2, [x8, :lo12:.LCPI24_0]
-; CHECK-GI-NEXT:    tbl.16b v0, { v0, v1 }, v2
-; CHECK-GI-NEXT:    ret
+; CHECK-LABEL: test_vrev16Q8:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ldr q0, [x0]
+; CHECK-NEXT:    rev16.16b v0, v0
+; CHECK-NEXT:    ret
 	%tmp1 = load <16 x i8>, ptr %A
 	%tmp2 = shufflevector <16 x i8> %tmp1, <16 x i8> undef, <16 x i32> <i32 1, i32 0, i32 3, i32 2, i32 5, i32 4, i32 7, i32 6, i32 9, i32 8, i32 11, i32 10, i32 13, i32 12, i32 15, i32 14>
 	ret <16 x i8> %tmp2
@@ -429,19 +375,11 @@ define <8 x i8> @test_vrev64D8_undef(ptr %A) nounwind {
 }
 
 define <8 x i16> @test_vrev32Q16_undef(ptr %A) nounwind {
-; CHECK-SD-LABEL: test_vrev32Q16_undef:
-; CHECK-SD:       // %bb.0:
-; CHECK-SD-NEXT:    ldr q0, [x0]
-; CHECK-SD-NEXT:    rev32.8h v0, v0
-; CHECK-SD-NEXT:    ret
-;
-; CHECK-GI-LABEL: test_vrev32Q16_undef:
-; CHECK-GI:       // %bb.0:
-; CHECK-GI-NEXT:    adrp x8, .LCPI26_0
-; CHECK-GI-NEXT:    ldr q0, [x0]
-; CHECK-GI-NEXT:    ldr q2, [x8, :lo12:.LCPI26_0]
-; CHECK-GI-NEXT:    tbl.16b v0, { v0, v1 }, v2
-; CHECK-GI-NEXT:    ret
+; CHECK-LABEL: test_vrev32Q16_undef:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ldr q0, [x0]
+; CHECK-NEXT:    rev32.8h v0, v0
+; CHECK-NEXT:    ret
 	%tmp1 = load <8 x i16>, ptr %A
 	%tmp2 = shufflevector <8 x i16> %tmp1, <8 x i16> undef, <8 x i32> <i32 undef, i32 0, i32 undef, i32 2, i32 5, i32 4, i32 7, i32 undef>
 	ret <8 x i16> %tmp2