[SCEV] Extend type hint in analysis output to all backedge kinds

This extends the work from 7755c26 to all of the different backend
taken count kinds that we print for the scev analysis printer.  As
before, the goal is to cut down on confusion as i4 -1 is a very
different (unsigned) value from i32 -1.

Author: preames

llvm/lib/Analysis/ScalarEvolution.cpp

@@ -13469,6 +13469,14 @@ bool ScalarEvolution::hasLoopInvariantBackedgeTakenCount(const Loop *L) {
   return !isa<SCEVCouldNotCompute>(getBackedgeTakenCount(L));
 }
 
+/// When printing a top-level SCEV for trip counts, it's helpful to include
+/// a type for constants which are otherwise hard to disambiguate.
+static void PrintSCEVWithTypeHint(raw_ostream &OS, const SCEV* S) {
+  if (isa<SCEVConstant>(S))
+    OS << *S->getType() << " ";
+  OS << *S;
+}
+
 static void PrintLoopInfo(raw_ostream &OS, ScalarEvolution *SE,
                           const Loop *L) {
   // Print all inner loops first
@@ -13485,15 +13493,18 @@ static void PrintLoopInfo(raw_ostream &OS, ScalarEvolution *SE,
     OS << "<multiple exits> ";
 
   auto *BTC = SE->getBackedgeTakenCount(L);
-  if (!isa<SCEVCouldNotCompute>(BTC))
-    OS << "backedge-taken count is " << *BTC << "\n";
-  else
-    OS << "Unpredictable backedge-taken count.\n";
+  if (!isa<SCEVCouldNotCompute>(BTC)) {
+    OS << "backedge-taken count is ";
+    PrintSCEVWithTypeHint(OS, BTC);
+  } else
+    OS << "Unpredictable backedge-taken count.";
+  OS << "\n";
 
   if (ExitingBlocks.size() > 1)
     for (BasicBlock *ExitingBlock : ExitingBlocks) {
-      OS << "  exit count for " << ExitingBlock->getName() << ": "
-         << *SE->getExitCount(L, ExitingBlock) << "\n";
+      OS << "  exit count for " << ExitingBlock->getName() << ": ";
+      PrintSCEVWithTypeHint(OS, SE->getExitCount(L, ExitingBlock));
+      OS << "\n";
     }
 
   OS << "Loop ";
@@ -13502,8 +13513,8 @@ static void PrintLoopInfo(raw_ostream &OS, ScalarEvolution *SE,
 
   auto *ConstantBTC = SE->getConstantMaxBackedgeTakenCount(L);
   if (!isa<SCEVCouldNotCompute>(ConstantBTC)) {
-    OS << "constant max backedge-taken count is "
-       << *ConstantBTC->getType() << " " << *ConstantBTC;
+    OS << "constant max backedge-taken count is ";
+    PrintSCEVWithTypeHint(OS, ConstantBTC);
     if (SE->isBackedgeTakenCountMaxOrZero(L))
       OS << ", actual taken count either this or zero.";
   } else {
@@ -13517,19 +13528,22 @@ static void PrintLoopInfo(raw_ostream &OS, ScalarEvolution *SE,
 
   auto *SymbolicBTC = SE->getSymbolicMaxBackedgeTakenCount(L);
   if (!isa<SCEVCouldNotCompute>(SymbolicBTC)) {
-    OS << "symbolic max backedge-taken count is " << *SymbolicBTC;
+    OS << "symbolic max backedge-taken count is ";
+    PrintSCEVWithTypeHint(OS, SymbolicBTC);
     if (SE->isBackedgeTakenCountMaxOrZero(L))
       OS << ", actual taken count either this or zero.";
   } else {
     OS << "Unpredictable symbolic max backedge-taken count. ";
   }
-
   OS << "\n";
+
   if (ExitingBlocks.size() > 1)
     for (BasicBlock *ExitingBlock : ExitingBlocks) {
-      OS << "  symbolic max exit count for " << ExitingBlock->getName() << ": "
-         << *SE->getExitCount(L, ExitingBlock, ScalarEvolution::SymbolicMaximum)
-         << "\n";
+      OS << "  symbolic max exit count for " << ExitingBlock->getName() << ": ";
+      auto *ExitBTC = SE->getExitCount(L, ExitingBlock,
+                                       ScalarEvolution::SymbolicMaximum);
+      PrintSCEVWithTypeHint(OS, ExitBTC);
+      OS << "\n";
     }
 
   SmallVector<const SCEVPredicate *, 4> Preds;
@@ -13538,10 +13552,12 @@ static void PrintLoopInfo(raw_ostream &OS, ScalarEvolution *SE,
     OS << "Loop ";
     L->getHeader()->printAsOperand(OS, /*PrintType=*/false);
     OS << ": ";
-    if (!isa<SCEVCouldNotCompute>(PBT))
-      OS << "Predicated backedge-taken count is " << *PBT << "\n";
-    else
-      OS << "Unpredictable predicated backedge-taken count.\n";
+    if (!isa<SCEVCouldNotCompute>(PBT)) {
+      OS << "Predicated backedge-taken count is ";
+      PrintSCEVWithTypeHint(OS, PBT);
+    } else
+      OS << "Unpredictable predicated backedge-taken count.";
+    OS << "\n";
     OS << " Predicates:\n";
     for (const auto *P : Preds)
       P->print(OS, 4);

llvm/test/Analysis/ScalarEvolution/2007-07-15-NegativeStride.ll

@@ -8,9 +8,9 @@
 define void @loop(i32 %x) {
 ; CHECK-LABEL: 'loop'
 ; CHECK-NEXT:  Determining loop execution counts for: @loop
-; CHECK-NEXT:  Loop %bb: backedge-taken count is 100
+; CHECK-NEXT:  Loop %bb: backedge-taken count is i32 100
 ; CHECK-NEXT:  Loop %bb: constant max backedge-taken count is i32 100
-; CHECK-NEXT:  Loop %bb: symbolic max backedge-taken count is 100
+; CHECK-NEXT:  Loop %bb: symbolic max backedge-taken count is i32 100
 ; CHECK-NEXT:  Loop %bb: Trip multiple is 101
 ;
 entry: