[CodeGen] Fix formatting and comments (NFC)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@363947 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/SwitchLoweringUtils.h

@@ -199,11 +199,11 @@ struct BitTestBlock {
         Cases(std::move(C)), Prob(Pr) {}
 };
 
-/// Return the range of value in [First..Last].
+/// Return the range of value within a range.
 uint64_t getJumpTableRange(const CaseClusterVector &Clusters, unsigned First,
                            unsigned Last);
 
-/// Return the number of cases in [First..Last].
+/// Return the number of cases within a range.
 uint64_t getJumpTableNumCases(const SmallVectorImpl<unsigned> &TotalCases,
                               unsigned First, unsigned Last);
 

include/llvm/CodeGen/TargetLowering.h

@@ -983,6 +983,7 @@ public:
     const unsigned MinDensity = getMinimumJumpTableDensity(OptForSize);
     const unsigned MaxJumpTableSize =
         OptForSize ? UINT_MAX : getMaximumJumpTableSize();
+
     // Check whether a range of clusters is dense enough for a jump table.
     if (Range <= MaxJumpTableSize &&
         (NumCases * 100 >= Range * MinDensity)) {

lib/CodeGen/SwitchLoweringUtils.cpp

@@ -27,7 +27,6 @@ uint64_t SwitchCG::getJumpTableRange(const CaseClusterVector &Clusters,
   // FIXME: A range of consecutive cases has 100% density, but only requires one
   // comparison to lower. We should discriminate against such consecutive ranges
   // in jump tables.
-
   return (HighCase - LowCase).getLimitedValue((UINT64_MAX - 1) / 100) + 1;
 }
 
@@ -56,14 +55,15 @@ void SwitchCG::SwitchLowering::findJumpTables(CaseClusterVector &Clusters,
   if (!TLI->areJTsAllowed(SI->getParent()->getParent()))
     return;
 
-  const int64_t N = Clusters.size();
   const unsigned MinJumpTableEntries = TLI->getMinimumJumpTableEntries();
   const unsigned SmallNumberOfEntries = MinJumpTableEntries / 2;
 
+  // Bail if not enough cases.
+  const int64_t N = Clusters.size();
   if (N < 2 || N < MinJumpTableEntries)
     return;
 
-  // TotalCases[i]: Total nbr of cases in Clusters[0..i].
+  // Accumulated number of cases in each cluster and those prior to it.
   SmallVector<unsigned, 8> TotalCases(N);
   for (unsigned i = 0; i < N; ++i) {
     const APInt &Hi = Clusters[i].High->getValue();
@@ -73,11 +73,12 @@ void SwitchCG::SwitchLowering::findJumpTables(CaseClusterVector &Clusters,
       TotalCases[i] += TotalCases[i - 1];
   }
 
-  // Cheap case: the whole range may be suitable for jump table.
   uint64_t Range = getJumpTableRange(Clusters,0, N - 1);
   uint64_t NumCases = getJumpTableNumCases(TotalCases, 0, N - 1);
   assert(NumCases < UINT64_MAX / 100);
   assert(Range >= NumCases);
+
+  // Cheap case: the whole range may be suitable for jump table.
   if (TLI->isSuitableForJumpTable(SI, NumCases, Range)) {
     CaseCluster JTCluster;
     if (buildJumpTable(Clusters, 0, N - 1, SI, DefaultMBB, JTCluster)) {
@@ -131,10 +132,11 @@ void SwitchCG::SwitchLowering::findJumpTables(CaseClusterVector &Clusters,
     // Search for a solution that results in fewer partitions.
     for (int64_t j = N - 1; j > i; j--) {
       // Try building a partition from Clusters[i..j].
-      uint64_t Range = getJumpTableRange(Clusters, i, j);
-      uint64_t NumCases = getJumpTableNumCases(TotalCases, i, j);
+      Range = getJumpTableRange(Clusters, i, j);
+      NumCases = getJumpTableNumCases(TotalCases, i, j);
       assert(NumCases < UINT64_MAX / 100);
       assert(Range >= NumCases);
+
       if (TLI->isSuitableForJumpTable(SI, NumCases, Range)) {
         unsigned NumPartitions = 1 + (j == N - 1 ? 0 : MinPartitions[j + 1]);
         unsigned Score = j == N - 1 ? 0 : PartitionsScore[j + 1];

test/CodeGen/AArch64/max-jump-table.ll

@@ -10,15 +10,15 @@ declare void @ext(i32, i32)
 define i32 @jt1(i32 %a, i32 %b) {
 entry:
   switch i32 %a, label %return [
-    i32 1, label %bb1
-    i32 2, label %bb2
-    i32 3, label %bb3
-    i32 4, label %bb4
-    i32 5, label %bb5
-    i32 6, label %bb6
-    i32 7, label %bb7
-    i32 8, label %bb8
-    i32 9, label %bb9
+    i32 1,  label %bb1
+    i32 2,  label %bb2
+    i32 3,  label %bb3
+    i32 4,  label %bb4
+    i32 5,  label %bb5
+    i32 6,  label %bb6
+    i32 7,  label %bb7
+    i32 8,  label %bb8
+    i32 9,  label %bb9
     i32 10, label %bb10
     i32 11, label %bb11
     i32 12, label %bb12
@@ -30,33 +30,33 @@ entry:
   ]
 ; CHECK-LABEL: function jt1:
 ; CHECK-NEXT: Jump Tables:
-; CHECK0-NEXT: %jump-table.0:  %bb.1 %bb.2 %bb.3 %bb.4 %bb.5 %bb.6 %bb.7 %bb.8 %bb.9 %bb.10 %bb.11 %bb.12 %bb.13 %bb.14 %bb.15 %bb.16 %bb.17
-; CHECK0-NOT: %jump-table.1:
-; CHECK4-NEXT: %jump-table.0:  %bb.2 %bb.3 %bb.4 %bb.5
-; CHECK4-SAME: %jump-table.1:  %bb.6 %bb.7 %bb.8 %bb.9
-; CHECK4-SAME: %jump-table.2:  %bb.10 %bb.11 %bb.12 %bb.13
-; CHECK4-SAME: %jump-table.3:  %bb.14 %bb.15 %bb.16 %bb.17
-; CHECK4-NOT: %jump-table.4:
-; CHECK8-NEXT: %jump-table.0:  %bb.2 %bb.3 %bb.4 %bb.5 %bb.6 %bb.7 %bb.8 %bb.9
-; CHECK8-SAME: %jump-table.1:  %bb.10 %bb.11 %bb.12 %bb.13 %bb.14 %bb.15 %bb.16 %bb.17
-; CHECK8-NOT: %jump-table.2:
-; CHECK16-NEXT: %jump-table.0:  %bb.2 %bb.3 %bb.4 %bb.5 %bb.6 %bb.7 %bb.8 %bb.9 %bb.10 %bb.11 %bb.12 %bb.13 %bb.14 %bb.15 %bb.16 %bb.17
-; CHECK16-NOT: %jump-table.1:
-; CHECKM1-NEXT: %jump-table.0:  %bb.2 %bb.3 %bb.4 %bb.5 %bb.6 %bb.7 %bb.8 %bb.9
-; CHECKM1-SAME: %jump-table.1:  %bb.10 %bb.11 %bb.12 %bb.13 %bb.14 %bb.15 %bb.16 %bb.17
-; CHECKM1-NOT: %jump-table.2:
-; CHECKM3-NEXT: %jump-table.0:  %bb.1 %bb.2 %bb.3 %bb.4 %bb.5 %bb.6 %bb.7 %bb.8 %bb.9 %bb.10 %bb.11 %bb.12 %bb.13 %bb.14 %bb.15 %bb.16 %bb.17
-; CHECKM3-NOT: %jump-table.1:
-
-bb1: tail call void  @ext(i32 1, i32 0) br label %return
-bb2: tail call void  @ext(i32 2, i32 2) br label %return
-bb3: tail call void  @ext(i32 3, i32 4) br label %return
-bb4: tail call void  @ext(i32 4, i32 6) br label %return
-bb5: tail call void  @ext(i32 5, i32 8) br label %return
-bb6: tail call void  @ext(i32 6, i32 10) br label %return
-bb7: tail call void  @ext(i32 7, i32 12) br label %return
-bb8: tail call void  @ext(i32 8, i32 14) br label %return
-bb9: tail call void  @ext(i32 9, i32 16) br label %return
+; CHECK0-NEXT:  %jump-table.0: %bb.1 %bb.2 %bb.3 %bb.4 %bb.5 %bb.6 %bb.7 %bb.8 %bb.9 %bb.10 %bb.11 %bb.12 %bb.13 %bb.14 %bb.15 %bb.16 %bb.17
+; CHECK0-NOT:   %jump-table.1:
+; CHECK4-NEXT:  %jump-table.0: %bb.2 %bb.3 %bb.4 %bb.5
+; CHECK4-SAME:  %jump-table.1: %bb.6 %bb.7 %bb.8 %bb.9
+; CHECK4-SAME:  %jump-table.2: %bb.10 %bb.11 %bb.12 %bb.13
+; CHECK4-SAME:  %jump-table.3: %bb.14 %bb.15 %bb.16 %bb.17
+; CHECK4-NOT:   %jump-table.4:
+; CHECK8-NEXT:  %jump-table.0: %bb.2 %bb.3 %bb.4 %bb.5 %bb.6 %bb.7 %bb.8 %bb.9
+; CHECK8-SAME:  %jump-table.1: %bb.10 %bb.11 %bb.12 %bb.13 %bb.14 %bb.15 %bb.16 %bb.17
+; CHECK8-NOT:   %jump-table.2:
+; CHECK16-NEXT: %jump-table.0: %bb.2 %bb.3 %bb.4 %bb.5 %bb.6 %bb.7 %bb.8 %bb.9 %bb.10 %bb.11 %bb.12 %bb.13 %bb.14 %bb.15 %bb.16 %bb.17
+; CHECK16-NOT:  %jump-table.1:
+; CHECKM1-NEXT: %jump-table.0: %bb.2 %bb.3 %bb.4 %bb.5 %bb.6 %bb.7 %bb.8 %bb.9
+; CHECKM1-SAME: %jump-table.1: %bb.10 %bb.11 %bb.12 %bb.13 %bb.14 %bb.15 %bb.16 %bb.17
+; CHECKM1-NOT:  %jump-table.2:
+; CHECKM3-NEXT: %jump-table.0: %bb.1 %bb.2 %bb.3 %bb.4 %bb.5 %bb.6 %bb.7 %bb.8 %bb.9 %bb.10 %bb.11 %bb.12 %bb.13 %bb.14 %bb.15 %bb.16 %bb.17
+; CHECKM3-NOT:  %jump-table.1:
+
+bb1:  tail call void @ext(i32 1, i32 0)  br label %return
+bb2:  tail call void @ext(i32 2, i32 2)  br label %return
+bb3:  tail call void @ext(i32 3, i32 4)  br label %return
+bb4:  tail call void @ext(i32 4, i32 6)  br label %return
+bb5:  tail call void @ext(i32 5, i32 8)  br label %return
+bb6:  tail call void @ext(i32 6, i32 10) br label %return
+bb7:  tail call void @ext(i32 7, i32 12) br label %return
+bb8:  tail call void @ext(i32 8, i32 14) br label %return
+bb9:  tail call void @ext(i32 9, i32 16) br label %return
 bb10: tail call void @ext(i32 1, i32 18) br label %return
 bb11: tail call void @ext(i32 2, i32 20) br label %return
 bb12: tail call void @ext(i32 3, i32 22) br label %return
@@ -72,28 +72,28 @@ return: ret i32 %b
 define void @jt2(i32 %x) {
 entry:
   switch i32 %x, label %return [
-    i32 1, label %bb1
-    i32 2, label %bb2
-    i32 3, label %bb3
-    i32 4, label %bb4
+    i32 1,  label %bb1
+    i32 2,  label %bb2
+    i32 3,  label %bb3
+    i32 4,  label %bb4
 
     i32 14, label %bb5
     i32 15, label %bb6
   ]
 ; CHECK-LABEL: function jt2:
 ; CHECK-NEXT: Jump Tables:
-; CHECK0-NEXT: %jump-table.0:  %bb.1 %bb.2 %bb.3 %bb.4 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.5 %bb.6{{$}}
-; CHECK0-NOT: %jump-table.1
-; CHECK4-NEXT: %jump-table.0:  %bb.1 %bb.2 %bb.3 %bb.4{{$}}
-; CHECK4-NOT: %jump-table.1
-; CHECK8-NEXT: %jump-table.0:  %bb.1 %bb.2 %bb.3 %bb.4{{$}}
-; CHECK8-NOT: %jump-table.1
-; CHECK16-NEXT: %jump-table.0:  %bb.1 %bb.2 %bb.3 %bb.4 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.5 %bb.6{{$}}
-; CHECK16-NOT: %jump-table.1:
-; CHECKM1-NEXT: %jump-table.0:  %bb.1 %bb.2 %bb.3 %bb.4{{$}}
-; CHECKM1-NOT: %jump-table.1
-; CHECKM3-NEXT: %jump-table.0:  %bb.1 %bb.2 %bb.3 %bb.4 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.5 %bb.6{{$}}
-; CHECKM3-NOT: %jump-table.1
+; CHECK0-NEXT:  %jump-table.0: %bb.1 %bb.2 %bb.3 %bb.4 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.5 %bb.6{{$}}
+; CHECK0-NOT:   %jump-table.1
+; CHECK4-NEXT:  %jump-table.0: %bb.1 %bb.2 %bb.3 %bb.4{{$}}
+; CHECK4-NOT:   %jump-table.1
+; CHECK8-NEXT:  %jump-table.0: %bb.1 %bb.2 %bb.3 %bb.4{{$}}
+; CHECK8-NOT:   %jump-table.1
+; CHECK16-NEXT: %jump-table.0: %bb.1 %bb.2 %bb.3 %bb.4 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.5 %bb.6{{$}}
+; CHECK16-NOT:  %jump-table.1:
+; CHECKM1-NEXT: %jump-table.0: %bb.1 %bb.2 %bb.3 %bb.4{{$}}
+; CHECKM1-NOT:  %jump-table.1
+; CHECKM3-NEXT: %jump-table.0: %bb.1 %bb.2 %bb.3 %bb.4 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.7 %bb.5 %bb.6{{$}}
+; CHECKM3-NOT:  %jump-table.1
 ; CHECK-DAG: End machine code for function jt2.
 
 bb1: tail call void @ext(i32 6, i32 1) br label %return
@@ -108,10 +108,10 @@ return: ret void
 define void @jt3(i32 %x) {
 entry:
   switch i32 %x, label %return [
-    i32 1, label %bb1
-    i32 2, label %bb2
-    i32 3, label %bb3
-    i32 4, label %bb4
+    i32 1,  label %bb1
+    i32 2,  label %bb2
+    i32 3,  label %bb3
+    i32 4,  label %bb4
 
     i32 14, label %bb5
     i32 15, label %bb6
@@ -144,18 +144,18 @@ entry:
 ; CHECKM3-NOT:  %jump-table.1
 ; CHECK-DAG: End machine code for function jt3.
 
-bb1: tail call void @ext(i32 1, i32 12) br label %return
-bb2: tail call void @ext(i32 2, i32 11) br label %return
-bb3: tail call void @ext(i32 3, i32 10) br label %return
-bb4: tail call void @ext(i32 4, i32 9) br label %return
-bb5: tail call void @ext(i32 5, i32 8) br label %return
-bb6: tail call void @ext(i32 6, i32 7) br label %return
-bb7: tail call void @ext(i32 7, i32 6) br label %return
-bb8: tail call void @ext(i32 8, i32 5) br label %return
-bb9: tail call void @ext(i32 9, i32 4) br label %return
-bb10: tail call void @ext(i32 10, i32 3) br label %return
-bb11: tail call void @ext(i32 11, i32 2) br label %return
-bb12: tail call void @ext(i32 12, i32 1) br label %return
+bb1:  tail call void @ext(i32 1,  i32 12) br label %return
+bb2:  tail call void @ext(i32 2,  i32 11) br label %return
+bb3:  tail call void @ext(i32 3,  i32 10) br label %return
+bb4:  tail call void @ext(i32 4,  i32 9)  br label %return
+bb5:  tail call void @ext(i32 5,  i32 8)  br label %return
+bb6:  tail call void @ext(i32 6,  i32 7)  br label %return
+bb7:  tail call void @ext(i32 7,  i32 6)  br label %return
+bb8:  tail call void @ext(i32 8,  i32 5)  br label %return
+bb9:  tail call void @ext(i32 9,  i32 4)  br label %return
+bb10: tail call void @ext(i32 10, i32 3)  br label %return
+bb11: tail call void @ext(i32 11, i32 2)  br label %return
+bb12: tail call void @ext(i32 12, i32 1)  br label %return
 
 return: ret void
 }
@@ -163,10 +163,10 @@ return: ret void
 define void @jt4(i32 %x) {
 entry:
   switch i32 %x, label %default [
-    i32 1, label %bb1
-    i32 2, label %bb2
-    i32 3, label %bb3
-    i32 4, label %bb4
+    i32 1,  label %bb1
+    i32 2,  label %bb2
+    i32 3,  label %bb3
+    i32 4,  label %bb4
 
     i32 14, label %bb5
     i32 15, label %bb6
@@ -199,18 +199,18 @@ entry:
 ; CHECKM3-NOT:  %jump-table.1
 ; CHECK-DAG: End machine code for function jt4.
 
-bb1: tail call void @ext(i32 1, i32 12) br label %return
-bb2: tail call void @ext(i32 2, i32 11) br label %return
-bb3: tail call void @ext(i32 3, i32 10) br label %return
-bb4: tail call void @ext(i32 4, i32 9) br label %return
-bb5: tail call void @ext(i32 5, i32 8) br label %return
-bb6: tail call void @ext(i32 6, i32 7) br label %return
-bb7: tail call void @ext(i32 7, i32 6) br label %return
-bb8: tail call void @ext(i32 8, i32 5) br label %return
-bb9: tail call void @ext(i32 9, i32 4) br label %return
-bb10: tail call void @ext(i32 10, i32 3) br label %return
-bb11: tail call void @ext(i32 11, i32 2) br label %return
-bb12: tail call void @ext(i32 12, i32 1) br label %return
+bb1:  tail call void @ext(i32 1,  i32 12) br label %return
+bb2:  tail call void @ext(i32 2,  i32 11) br label %return
+bb3:  tail call void @ext(i32 3,  i32 10) br label %return
+bb4:  tail call void @ext(i32 4,  i32 9)  br label %return
+bb5:  tail call void @ext(i32 5,  i32 8)  br label %return
+bb6:  tail call void @ext(i32 6,  i32 7)  br label %return
+bb7:  tail call void @ext(i32 7,  i32 6)  br label %return
+bb8:  tail call void @ext(i32 8,  i32 5)  br label %return
+bb9:  tail call void @ext(i32 9,  i32 4)  br label %return
+bb10: tail call void @ext(i32 10, i32 3)  br label %return
+bb11: tail call void @ext(i32 11, i32 2)  br label %return
+bb12: tail call void @ext(i32 12, i32 1)  br label %return
 default: unreachable
 
 return: ret void

test/CodeGen/AArch64/min-jump-table.ll

@@ -71,4 +71,3 @@ bb8: tail call void @ext(i32 8, i32 14) br label %return
 
 return: ret i32 %b
 }
-