[llvm] [DAGCombiner] Remove NoNaNsFPMath uses in visitFADD (PR #163504)

[via llvm-commits]

https://github.com/paperchalice updated https://github.com/llvm/llvm-project/pull/163504

>From 3eb2a9e9d8a78a3ca699ef1a0b3a558ea9c1f67d Mon Sep 17 00:00:00 2001
From: PaperChalice <liujunchang97 at outlook.com>
Date: Wed, 15 Oct 2025 14:17:06 +0800
Subject: [PATCH 1/2] [DAGCombiner] Remove NoNaNsFPMath uses in visitFADD

---
 llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 358e060d2c6d3..9d1b8bfe6c074 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -17759,7 +17759,6 @@ SDValue DAGCombiner::visitFADD(SDNode *N) {
   bool N1CFP = DAG.isConstantFPBuildVectorOrConstantFP(N1);
   EVT VT = N->getValueType(0);
   SDLoc DL(N);
-  const TargetOptions &Options = DAG.getTarget().Options;
   SDNodeFlags Flags = N->getFlags();
   SelectionDAG::FlagInserter FlagsInserter(DAG, N);
 
@@ -17825,7 +17824,7 @@ SDValue DAGCombiner::visitFADD(SDNode *N) {
   bool AllowNewConst = (Level < AfterLegalizeDAG);
 
   // If nnan is enabled, fold lots of things.
-  if ((Options.NoNaNsFPMath || Flags.hasNoNaNs()) && AllowNewConst) {
+  if (Flags.hasNoNaNs() && AllowNewConst) {
     // If allowed, fold (fadd (fneg x), x) -> 0.0
     if (N0.getOpcode() == ISD::FNEG && N0.getOperand(0) == N1)
       return DAG.getConstantFP(0.0, DL, VT);

>From 81175a2343a3dfdd8ea1dec011498cf8c3a0eadb Mon Sep 17 00:00:00 2001
From: PaperChalice <liujunchang97 at outlook.com>
Date: Wed, 15 Oct 2025 14:43:37 +0800
Subject: [PATCH 2/2] Remove NoNaNsFPMath in visitFSUB

---
 llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 9d1b8bfe6c074..eb722acd911fd 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -17973,7 +17973,6 @@ SDValue DAGCombiner::visitFSUB(SDNode *N) {
   ConstantFPSDNode *N1CFP = isConstOrConstSplatFP(N1, true);
   EVT VT = N->getValueType(0);
   SDLoc DL(N);
-  const TargetOptions &Options = DAG.getTarget().Options;
   const SDNodeFlags Flags = N->getFlags();
   SelectionDAG::FlagInserter FlagsInserter(DAG, N);
 
@@ -18001,7 +18000,7 @@ SDValue DAGCombiner::visitFSUB(SDNode *N) {
 
   if (N0 == N1) {
     // (fsub x, x) -> 0.0
-    if (Options.NoNaNsFPMath || Flags.hasNoNaNs())
+    if (Flags.hasNoNaNs())
       return DAG.getConstantFP(0.0f, DL, VT);
   }