[AIE2] Shuffle pattern for reversing vector order

Author: ValentijnvdBeek

llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp

@@ -381,20 +381,21 @@ bool CombinerHelper::tryCombineShuffleVector(MachineInstr &MI) {
   const unsigned DstNumElts = DstTy.isVector() ? DstTy.getNumElements() : 1;
   const unsigned SrcNumElts = SrcTy.isVector() ? SrcTy.getNumElements() : 1;
 
+  // type helper
+  using generator = std::function<std::optional<int32_t>()>;
+
   // {1, 2, ..., n} -> G_CONCAT_VECTOR
   // Turns a shuffle vector that only increments into a concat vector
   // instruction
-  std::function<std::optional<int32_t>()> CountUp =
-      adderGenerator(0, DstNumElts - 1, 1);
+  generator CountUp = adderGenerator(0, DstNumElts - 1, 1);
   if (matchCombineShuffleVector(MI, Ops, CountUp, 2 * SrcNumElts)) {
     applyCombineShuffleVector(MI, Ops);
     return true;
   }
 
   // {1, 2, ..., |DstVector|} -> G_UNMERGE_VALUES
   // Extracts the first chunk of the same size of the destination vector from the source
-  std::function<std::optional<int32_t>()> FirstQuarter =
-      adderGenerator(0, DstNumElts - 1, 1);
+  generator FirstQuarter = adderGenerator(0, DstNumElts - 1, 1);
   if (matchCombineShuffleVectorSimple(MI, FirstQuarter, DstNumElts - 1)) {
     if (SrcTy == DstTy || ((SrcNumElts / 2) % 2) != 0)
       return false;
@@ -405,8 +406,7 @@ bool CombinerHelper::tryCombineShuffleVector(MachineInstr &MI) {
 
   // {|DstVector|, |DstVector|+1, ..., 2 * |DstVector|} -> G_UNMERGE_VALUES
   // Extracts the second chunk of the same size of the destination vector from the source
-  std::function<std::optional<int32_t>()> SecondQuarter =
-      adderGenerator(DstNumElts, (DstNumElts * 2) - 1, 1);
+  generator SecondQuarter = adderGenerator(DstNumElts, (DstNumElts * 2) - 1, 1);
   if (matchCombineShuffleVectorSimple(MI, SecondQuarter, DstNumElts - 1)) {
     if (((SrcNumElts / 2) % 2) != 0)
       return false;
@@ -418,14 +418,12 @@ bool CombinerHelper::tryCombineShuffleVector(MachineInstr &MI) {
   // {1, 2, ..., n/4, n/2, n/2+1, .... 3n/4} -> G_UNMERGE_VALUES
   // Take the first halfs of the two vectors and concatenate them into one
   // vector.
-  std::function<std::optional<int32_t>()> FirstEightA =
-      adderGenerator(0, (DstNumElts / 2) - 1, 1);
-  std::function<std::optional<int32_t>()> FirstEightB =
+  generator FirstEightA = adderGenerator(0, (DstNumElts / 2) - 1, 1);
+  generator FirstEightB =
       adderGenerator(DstNumElts, DstNumElts + (DstNumElts / 2) - 1, 1);
 
-  std::function<std::optional<int32_t>()> FirstAndThird =
-      concatGenerators(SmallVector<std::function<std::optional<int32_t>()>>{
-          FirstEightA, FirstEightB});
+  generator FirstAndThird =
+      concatGenerators(SmallVector<generator>{FirstEightA, FirstEightB});
   if (matchCombineShuffleVectorSimple(MI, FirstAndThird,
                                       (DstNumElts / 2) - 1)) {
     if (DstNumElts <= 2)
@@ -443,6 +441,18 @@ bool CombinerHelper::tryCombineShuffleVector(MachineInstr &MI) {
     MI.eraseFromParent();
     return true;
   }
+
+  // {n/2, n/2+1, ..., n, 0, 1, ..., n/2-1}
+  generator FirstHalf = adderGenerator(0, SrcNumElts / 2, 1);
+  generator SecondHalf = adderGenerator(SrcNumElts / 2, SrcNumElts, 1);
+  generator Reverse =
+      concatGenerators(SmallVector<generator>{FirstHalf, SecondHalf});
+
+  if (matchCombineShuffleVectorSimple(MI, Reverse, SrcNumElts)) {
+    applyCombineShuffleVector(MI, {Ops[1], Ops[0]});
+    return true;
+  }
+
   return false;
 }
 

llvm/test/CodeGen/AIE/aie2/GlobalISel/prelegalizercombiner-shufflevector.mir

@@ -327,3 +327,23 @@ body:             |
     %2:_(<128 x s8>) = COPY $y3
     %3:_(<128 x s8>) = G_SHUFFLE_VECTOR %1:_(<128 x s8>), %2:_(<128 x s8>), shufflemask(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191)
     PseudoRET implicit $lr, implicit %3
+---
+name:            concat_vector_reverse_32_512
+legalized:       false
+body:             |
+  bb.1.entry:
+    liveins: $wl2, $wl4
+    ; CHECK-LABEL: name: concat_vector_reverse_32_512
+    ; CHECK: liveins: $wl2, $wl4
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:_(<8 x s32>) = COPY $wl2
+    ; CHECK-NEXT: [[COPY1:%[0-9]+]]:_(<8 x s32>) = COPY $wl4
+    ; CHECK-NEXT: [[CONCAT_VECTORS:%[0-9]+]]:_(<16 x s32>) = G_CONCAT_VECTORS [[COPY1]](<8 x s32>), [[COPY]](<8 x s32>)
+    ; CHECK-NEXT: $x0 = COPY [[CONCAT_VECTORS]](<16 x s32>)
+    ; CHECK-NEXT: PseudoRET implicit $lr, implicit $x0
+    %1:_(<8 x s32>) = COPY $wl2
+    %2:_(<8 x s32>) = COPY $wl4
+    %0:_(<16 x s32>) = G_SHUFFLE_VECTOR %1:_(<8 x s32>), %2:_, shufflemask(8, 9, 10, 11, 12, 13, 14, 15, 0, 1, 2, 3, 4, 5, 6, 7)
+    $x0 = COPY %0:_(<16 x s32>)
+    PseudoRET implicit $lr, implicit $x0
+...