2 files changed, 59 insertions, 35 deletions

diff --git a/llvm/lib/Analysis/ConstantFolding.cpp b/llvm/lib/Analysis/ConstantFolding.cpp
index e9e2e7d..da32542 100755
--- a/llvm/lib/Analysis/ConstantFolding.cpp
+++ b/llvm/lib/Analysis/ConstantFolding.cpp
@@ -2163,18 +2163,42 @@ Constant *ConstantFoldBinaryFP(double (*NativeFP)(double, double),
 }
 
 Constant *constantFoldVectorReduce(Intrinsic::ID IID, Constant *Op) {
-  FixedVectorType *VT = dyn_cast<FixedVectorType>(Op->getType());
-  if (!VT)
-    return nullptr;
-
-  // This isn't strictly necessary, but handle the special/common case of zero:
-  // all integer reductions of a zero input produce zero.
-  if (isa<ConstantAggregateZero>(Op))
-    return ConstantInt::get(VT->getElementType(), 0);
+  auto *OpVT = cast<VectorType>(Op->getType());
 
   // This is the same as the underlying binops - poison propagates.
-  if (isa<PoisonValue>(Op) || Op->containsPoisonElement())
-    return PoisonValue::get(VT->getElementType());
+  if (Op->containsPoisonElement())
+    return PoisonValue::get(OpVT->getElementType());
+
+  // Shortcut non-accumulating reductions.
+  if (Constant *SplatVal = Op->getSplatValue()) {
+    switch (IID) {
+    case Intrinsic::vector_reduce_and:
+    case Intrinsic::vector_reduce_or:
+    case Intrinsic::vector_reduce_smin:
+    case Intrinsic::vector_reduce_smax:
+    case Intrinsic::vector_reduce_umin:
+    case Intrinsic::vector_reduce_umax:
+      return SplatVal;
+    case Intrinsic::vector_reduce_add:
+      if (SplatVal->isNullValue())
+        return SplatVal;
+      break;
+    case Intrinsic::vector_reduce_mul:
+      if (SplatVal->isNullValue() || SplatVal->isOneValue())
+        return SplatVal;
+      break;
+    case Intrinsic::vector_reduce_xor:
+      if (SplatVal->isNullValue())
+        return SplatVal;
+      if (OpVT->getElementCount().isKnownMultipleOf(2))
+        return Constant::getNullValue(OpVT->getElementType());
+      break;
+    }
+  }
+
+  FixedVectorType *VT = dyn_cast<FixedVectorType>(OpVT);
+  if (!VT)
+    return nullptr;
 
   // TODO: Handle undef.
   auto *EltC = dyn_cast_or_null<ConstantInt>(Op->getAggregateElement(0U));
diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index 7597f3a..c9baeda 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -15670,31 +15670,31 @@ void ScalarEvolution::LoopGuards::collectFromBlock(
     // predicate.
     const SCEV *One = SE.getOne(RHS->getType());
     switch (Predicate) {
-      case CmpInst::ICMP_ULT:
-        if (RHS->getType()->isPointerTy())
-          return;
-        RHS = SE.getUMaxExpr(RHS, One);
-        [[fallthrough]];
-      case CmpInst::ICMP_SLT: {
-        RHS = SE.getMinusSCEV(RHS, One);
-        RHS = getPreviousSCEVDivisibleByDivisor(RHS, DividesBy, SE);
-        break;
-      }
-      case CmpInst::ICMP_UGT:
-      case CmpInst::ICMP_SGT:
-        RHS = SE.getAddExpr(RHS, One);
-        RHS = getNextSCEVDivisibleByDivisor(RHS, DividesBy, SE);
-        break;
-      case CmpInst::ICMP_ULE:
-      case CmpInst::ICMP_SLE:
-        RHS = getPreviousSCEVDivisibleByDivisor(RHS, DividesBy, SE);
-        break;
-      case CmpInst::ICMP_UGE:
-      case CmpInst::ICMP_SGE:
-        RHS = getNextSCEVDivisibleByDivisor(RHS, DividesBy, SE);
-        break;
-      default:
-        break;
+    case CmpInst::ICMP_ULT:
+      if (RHS->getType()->isPointerTy())
+        return;
+      RHS = SE.getUMaxExpr(RHS, One);
+      [[fallthrough]];
+    case CmpInst::ICMP_SLT: {
+      RHS = SE.getMinusSCEV(RHS, One);
+      RHS = getPreviousSCEVDivisibleByDivisor(RHS, DividesBy, SE);
+      break;
+    }
+    case CmpInst::ICMP_UGT:
+    case CmpInst::ICMP_SGT:
+      RHS = SE.getAddExpr(RHS, One);
+      RHS = getNextSCEVDivisibleByDivisor(RHS, DividesBy, SE);
+      break;
+    case CmpInst::ICMP_ULE:
+    case CmpInst::ICMP_SLE:
+      RHS = getPreviousSCEVDivisibleByDivisor(RHS, DividesBy, SE);
+      break;
+    case CmpInst::ICMP_UGE:
+    case CmpInst::ICMP_SGE:
+      RHS = getNextSCEVDivisibleByDivisor(RHS, DividesBy, SE);
+      break;
+    default:
+      break;
     }
 
     SmallVector<const SCEV *, 16> Worklist(1, LHS);