[Analysis][LV] Handle FMinNum/FMaxNum in RecurrenceDescriptor::getOpcode

Teach getOpcode to return FCmp for FMinNum/FMaxNum. Without these cases, passes that query the opcode for minNum/maxNum reductions can hit llvm_unreachable. Add a unit test to cover both enums.

Author: Uyiosa Iyekekpolor

llvm/lib/Analysis/IVDescriptors.cpp

@@ -1228,6 +1228,8 @@ unsigned RecurrenceDescriptor::getOpcode(RecurKind Kind) {
     return Instruction::ICmp;
   case RecurKind::FMax:
   case RecurKind::FMin:
+  case RecurKind::FMaxNum:
+  case RecurKind::FMinNum:
   case RecurKind::FMaximum:
   case RecurKind::FMinimum:
   case RecurKind::FMaximumNum:

llvm/unittests/Analysis/IVDescriptorsTest.cpp

@@ -259,3 +259,12 @@ for.end:
         EXPECT_EQ(Kind, RecurKind::FMax);
       });
 }
+
+TEST(IVDescriptorsTest, GetOpcodeForFMinMaxNum) {
+  using RK = RecurKind;
+  // Ensure the "num" variants map to the same opcode as the plain ones.
+  EXPECT_EQ(RecurrenceDescriptor::getOpcode(RK::FMinNum),
+    RecurrenceDescriptor::getOpcode(RK::FMin));
+  EXPECT_EQ(RecurrenceDescriptor::getOpcode(RK::FMinNum),
+    RecurrenceDescriptor::getOpcode(RK::FMin));
+}