[llvm] [VPlan] Support multiple F(Max|Min)Num reductions. (PR #161735)

[Mel Chen via llvm-commits]

================
@@ -884,52 +871,69 @@ bool VPlanTransforms::handleMaxMinNumReductions(VPlan &Plan) {
   }
 
   VPBasicBlock *LatchVPBB = LoopRegion->getExitingBasicBlock();
+  VPBasicBlock *MiddleVPBB = Plan.getMiddleBlock();
+  VPBuilder MiddleBuilder(MiddleVPBB, MiddleVPBB->begin());
   VPBuilder Builder(LatchVPBB->getTerminator());
-  auto *LatchExitingBranch = cast<VPInstruction>(LatchVPBB->getTerminator());
-  assert(LatchExitingBranch->getOpcode() == VPInstruction::BranchOnCount &&
+  VPValue *AnyNaN = nullptr;
+  SmallPtrSet<VPValue *, 2> RdxResults;
+  for (VPReductionPHIRecipe *RedPhiR : ReductionsToConvert) {
+    VPValue *MinMaxOp = GetMinMaxCompareValue(RedPhiR);
+    if (!MinMaxOp)
+      return false;
+
+    RecurKind RedPhiRK = RedPhiR->getRecurrenceKind();
+    assert((RedPhiRK == RecurKind::FMaxNum || RedPhiRK == RecurKind::FMinNum) &&
+           "unsupported reduction");
+    (void)RedPhiRK;
----------------
Mel-Chen wrote:

Could this assertion be moved to the beginning of the for loop?

https://github.com/llvm/llvm-project/pull/161735