[ConstantFolding] Fold maximumnum and minimumnum (#138700)

Add constant-folding support for the maximumnum and minimumnum
intrinsics, and extend the tests to show the qnan vs snan behavior
differences between maxnum/maximum/maximumnum.

Author: LewisCrawford

llvm/lib/Analysis/ConstantFolding.cpp

@@ -1642,6 +1642,8 @@ bool llvm::canConstantFoldCallTo(const CallBase *Call, const Function *F) {
   case Intrinsic::maxnum:
   case Intrinsic::minimum:
   case Intrinsic::maximum:
+  case Intrinsic::minimumnum:
+  case Intrinsic::maximumnum:
   case Intrinsic::log:
   case Intrinsic::log2:
   case Intrinsic::log10:
@@ -2930,6 +2932,8 @@ static Constant *ConstantFoldIntrinsicCall2(Intrinsic::ID IntrinsicID, Type *Ty,
     case Intrinsic::minnum:
     case Intrinsic::maximum:
     case Intrinsic::minimum:
+    case Intrinsic::maximumnum:
+    case Intrinsic::minimumnum:
     case Intrinsic::nvvm_fmax_d:
     case Intrinsic::nvvm_fmin_d:
       // If one argument is undef, return the other argument.
@@ -3030,6 +3034,10 @@ static Constant *ConstantFoldIntrinsicCall2(Intrinsic::ID IntrinsicID, Type *Ty,
         return ConstantFP::get(Ty->getContext(), minimum(Op1V, Op2V));
       case Intrinsic::maximum:
         return ConstantFP::get(Ty->getContext(), maximum(Op1V, Op2V));
+      case Intrinsic::minimumnum:
+        return ConstantFP::get(Ty->getContext(), minimumnum(Op1V, Op2V));
+      case Intrinsic::maximumnum:
+        return ConstantFP::get(Ty->getContext(), maximumnum(Op1V, Op2V));
 
       case Intrinsic::nvvm_fmax_d:
       case Intrinsic::nvvm_fmax_f:

llvm/test/Transforms/InstSimplify/ConstProp/fp-undef.ll

@@ -5,6 +5,8 @@ declare <2 x double> @llvm.minnum.v2f64(<2 x double>, <2 x double>)
 declare <2 x double> @llvm.maxnum.v2f64(<2 x double>, <2 x double>)
 declare <2 x double> @llvm.minimum.v2f64(<2 x double>, <2 x double>)
 declare <2 x double> @llvm.maximum.v2f64(<2 x double>, <2 x double>)
+declare <2 x double> @llvm.minimumnum.v2f64(<2 x double>, <2 x double>)
+declare <2 x double> @llvm.maximumnum.v2f64(<2 x double>, <2 x double>)
 
 ; Constant folding - undef undef.
 
@@ -538,6 +540,38 @@ define <2 x double> @frem_undef_op0_constant_vec(<2 x double> %x) {
   ret <2 x double> %r
 }
 
+define <2 x double> @maximumnum_nan_op0_vec_partial_poison_op1_poison(<2 x double> %x) {
+; CHECK-LABEL: @maximumnum_nan_op0_vec_partial_poison_op1_poison(
+; CHECK-NEXT:    ret <2 x double> <double 0x7FF8000000000000, double poison>
+;
+  %r = call <2 x double> @llvm.maximumnum.v2f64(<2 x double> <double 0x7ff8000000000000, double poison>, <2 x double> poison)
+  ret <2 x double> %r
+}
+
+define <2 x double> @maximumnum_nan_op1_vec_partial_poison_op0_poison(<2 x double> %x) {
+; CHECK-LABEL: @maximumnum_nan_op1_vec_partial_poison_op0_poison(
+; CHECK-NEXT:    ret <2 x double> <double 0x7FF8000000000000, double poison>
+;
+  %r = call <2 x double> @llvm.maximumnum.v2f64(<2 x double> poison, <2 x double> <double 0x7ff8000000000000, double poison>)
+  ret <2 x double> %r
+}
+
+define <2 x double> @minimumnum_nan_op0_vec_partial_poison_op1_poison(<2 x double> %x) {
+; CHECK-LABEL: @minimumnum_nan_op0_vec_partial_poison_op1_poison(
+; CHECK-NEXT:    ret <2 x double> <double 0x7FF8000000000000, double poison>
+;
+  %r = call <2 x double> @llvm.minimumnum.v2f64(<2 x double> <double 0x7ff8000000000000, double poison>, <2 x double> poison)
+  ret <2 x double> %r
+}
+
+define <2 x double> @minimumnum_nan_op1_vec_partial_poison_op0_poison(<2 x double> %x) {
+; CHECK-LABEL: @minimumnum_nan_op1_vec_partial_poison_op0_poison(
+; CHECK-NEXT:    ret <2 x double> <double 0x7FF8000000000000, double poison>
+;
+  %r = call <2 x double> @llvm.minimumnum.v2f64(<2 x double> poison, <2 x double> <double 0x7ff8000000000000, double poison>)
+  ret <2 x double> %r
+}
+
 define <2 x double> @maximum_nan_op0_vec_partial_undef_op1_undef(<2 x double> %x) {
 ; CHECK-LABEL: @maximum_nan_op0_vec_partial_undef_op1_undef(
 ; CHECK-NEXT:    ret <2 x double> <double 0x7FF8000000000000, double undef>