[llvm] AArch64: Set FMAXIMUMNUM and FMINIMUMNUM as Promote if not fullfp16 (PR #135708)

[YunQiang Su via llvm-commits]

https://github.com/wzssyqa created https://github.com/llvm/llvm-project/pull/135708

Since Promote will emit FP_EXTEND, the result of it will never be sNaN, so we don't need worry about duplicated of FCANONICALIZE in expandFMINIMUMNUM_FMAXIMUMNUM.

>From 687926f501413cbfce01010916e0b63ed60c5f6e Mon Sep 17 00:00:00 2001
From: YunQiang Su <yunqiang at isrc.iscas.ac.cn>
Date: Tue, 15 Apr 2025 08:29:41 +0800
Subject: [PATCH] AArch64: Set FMAXIMUMNUM and FMINIMUMNUM as Promote if not
 fullfp16

Since Promote will emit FP_EXTEND, the result of it will never be
sNaN, so we don't need worry about duplicated of FCANONICALIZE in
expandFMINIMUMNUM_FMAXIMUMNUM.
---
 .../Target/AArch64/AArch64ISelLowering.cpp    |  2 ++
 .../CodeGen/AArch64/fminmax-f16-promote.ll    | 28 +++++++++++++++++++
 2 files changed, 30 insertions(+)
 create mode 100644 llvm/test/CodeGen/AArch64/fminmax-f16-promote.ll

diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
index 830ec6886e6bc..bea8087750d6e 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -795,6 +795,8 @@ AArch64TargetLowering::AArch64TargetLowering(const TargetMachine &TM,
              ISD::FMAXNUM,
              ISD::FMINIMUM,
              ISD::FMAXIMUM,
+             ISD::FMINIMUMNUM,
+             ISD::FMAXIMUMNUM,
              ISD::FCANONICALIZE,
              ISD::STRICT_FADD,
              ISD::STRICT_FSUB,
diff --git a/llvm/test/CodeGen/AArch64/fminmax-f16-promote.ll b/llvm/test/CodeGen/AArch64/fminmax-f16-promote.ll
new file mode 100644
index 0000000000000..abd0a8e6591ec
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/fminmax-f16-promote.ll
@@ -0,0 +1,28 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc -mtriple=aarch64 -verify-machineinstrs %s -o - | FileCheck %s
+
+define half @min(half noundef %a, half noundef %b) {
+; CHECK-LABEL: min:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    fcvt s1, h1
+; CHECK-NEXT:    fcvt s0, h0
+; CHECK-NEXT:    fminnm s0, s0, s1
+; CHECK-NEXT:    fcvt h0, s0
+; CHECK-NEXT:    ret
+entry:
+  %0 = tail call half @llvm.minimumnum.f16(half %a, half %b)
+  ret half %0
+}
+
+define half @max(half noundef %a, half noundef %b) {
+; CHECK-LABEL: max:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    fcvt s1, h1
+; CHECK-NEXT:    fcvt s0, h0
+; CHECK-NEXT:    fmaxnm s0, s0, s1
+; CHECK-NEXT:    fcvt h0, s0
+; CHECK-NEXT:    ret
+entry:
+  %0 = tail call half @llvm.maximumnum.f16(half %a, half %b)
+  ret half %0
+}