[llvm] Draft: [DAGCombiner] Remove all `UnsafeFPMath` references (PR #146295)

[via llvm-commits]

https://github.com/paperchalice created https://github.com/llvm/llvm-project/pull/146295

None

>From 5dda9d969699ed03538cdc65a56b3e4942aa9a5e Mon Sep 17 00:00:00 2001
From: PaperChalice <liujunchang97 at outlook.com>
Date: Mon, 30 Jun 2025 09:14:24 +0800
Subject: [PATCH] remove `UnsafeFPMath` usages in `visitFADD`

---
 llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 8554db0a1220c..b8e1da4749540 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -17581,7 +17581,7 @@ SDValue DAGCombiner::visitFADD(SDNode *N) {
   // If 'unsafe math' or reassoc and nsz, fold lots of things.
   // TODO: break out portions of the transformations below for which Unsafe is
   //       considered and which do not require both nsz and reassoc
-  if (((Options.UnsafeFPMath && Options.NoSignedZerosFPMath) ||
+  if ((Options.NoSignedZerosFPMath ||
        (Flags.hasAllowReassociation() && Flags.hasNoSignedZeros())) &&
       AllowNewConst) {
     // fadd (fadd x, c1), c2 -> fadd x, c1 + c2
@@ -17668,7 +17668,7 @@ SDValue DAGCombiner::visitFADD(SDNode *N) {
     }
   } // enable-unsafe-fp-math && AllowNewConst
 
-  if (((Options.UnsafeFPMath && Options.NoSignedZerosFPMath) ||
+  if ((Options.NoSignedZerosFPMath ||
        (Flags.hasAllowReassociation() && Flags.hasNoSignedZeros()))) {
     // Fold fadd(vecreduce(x), vecreduce(y)) -> vecreduce(fadd(x, y))
     if (SDValue SD = reassociateReduction(ISD::VECREDUCE_FADD, ISD::FADD, DL,