[IVDescriptors] Support reductions with minimumnum/maximumnum. (#137335)

Add a new reduction recurrence kind for reductions with
minimumnum/maximumnum. Such reductions can be vectorized without
nsz/nnans, same as reductions with maximum/minimum intrinsics.

Note that a new reduction kind is needed to make sure partial reductions
are also combined with minimumnum/maximumnum.

Note that the final reduction to a scalar value is performed with
vector.reduce.fmin/fmax. This should be fine, as the results of the
partial reductions with maximumnum/minimumnum silences any sNaNs.

In-loop and reductions in SLP are not supported yet, as there's no
reduction version of maximumnum/minimumnum yet and fmax may be
incorrect.

PR: https://github.com/llvm/llvm-project/pull/137335

1 files changed, 12 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Utils/LoopUtils.cpp b/llvm/lib/Transforms/Utils/LoopUtils.cpp
index f57d95e..2fff9521 100644
--- a/llvm/lib/Transforms/Utils/LoopUtils.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUtils.cpp
@@ -958,6 +958,10 @@ constexpr Intrinsic::ID llvm::getReductionIntrinsicID(RecurKind RK) {
     return Intrinsic::vector_reduce_fmaximum;
   case RecurKind::FMinimum:
     return Intrinsic::vector_reduce_fminimum;
+  case RecurKind::FMaximumNum:
+    return Intrinsic::vector_reduce_fmax;
+  case RecurKind::FMinimumNum:
+    return Intrinsic::vector_reduce_fmin;
   }
 }
 
@@ -1053,6 +1057,10 @@ Intrinsic::ID llvm::getMinMaxReductionIntrinsicOp(RecurKind RK) {
     return Intrinsic::minimum;
   case RecurKind::FMaximum:
     return Intrinsic::maximum;
+  case RecurKind::FMinimumNum:
+    return Intrinsic::minimumnum;
+  case RecurKind::FMaximumNum:
+    return Intrinsic::maximumnum;
   }
 }
 
@@ -1101,7 +1109,8 @@ Value *llvm::createMinMaxOp(IRBuilderBase &Builder, RecurKind RK, Value *Left,
                             Value *Right) {
   Type *Ty = Left->getType();
   if (Ty->isIntOrIntVectorTy() ||
-      (RK == RecurKind::FMinimum || RK == RecurKind::FMaximum)) {
+      (RK == RecurKind::FMinimum || RK == RecurKind::FMaximum ||
+       RK == RecurKind::FMinimumNum || RK == RecurKind::FMaximumNum)) {
     // TODO: Add float minnum/maxnum support when FMF nnan is set.
     Intrinsic::ID Id = getMinMaxReductionIntrinsicOp(RK);
     return Builder.CreateIntrinsic(Ty, Id, {Left, Right}, nullptr,
@@ -1320,6 +1329,8 @@ Value *llvm::createSimpleReduction(IRBuilderBase &Builder, Value *Src,
   case RecurKind::FMin:
   case RecurKind::FMinimum:
   case RecurKind::FMaximum:
+  case RecurKind::FMinimumNum:
+  case RecurKind::FMaximumNum:
     return Builder.CreateUnaryIntrinsic(getReductionIntrinsicID(RdxKind), Src);
   case RecurKind::FMulAdd:
   case RecurKind::FAdd: