[llvm] [SelectionDAG] Remove the remained `NoSignedZerosFPMath` use (PR #201535)

[via llvm-commits]

https://github.com/paperchalice created https://github.com/llvm/llvm-project/pull/201535

This should be the last use.

>From 3108457562ba37411fad0d200284b1dd7b29d96b Mon Sep 17 00:00:00 2001
From: PaperChalice <liujunchang97 at outlook.com>
Date: Thu, 4 Jun 2026 17:01:56 +0800
Subject: [PATCH 1/2] [SelectionDAG] Propagate fast-math flags from {u,s}itofp

---
 llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index eca5bb1598ae0..5c71863254d1e 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -4054,6 +4054,7 @@ void SelectionDAGBuilder::visitUIToFP(const User &I) {
   SDNodeFlags Flags;
   if (auto *PNI = dyn_cast<PossiblyNonNegInst>(&I))
     Flags.setNonNeg(PNI->hasNonNeg());
+  Flags.copyFMF(*cast<FPMathOperator>(&I));
 
   setValue(&I, DAG.getNode(ISD::UINT_TO_FP, getCurSDLoc(), DestVT, N, Flags));
 }
@@ -4063,7 +4064,9 @@ void SelectionDAGBuilder::visitSIToFP(const User &I) {
   SDValue N = getValue(I.getOperand(0));
   EVT DestVT = DAG.getTargetLoweringInfo().getValueType(DAG.getDataLayout(),
                                                         I.getType());
-  setValue(&I, DAG.getNode(ISD::SINT_TO_FP, getCurSDLoc(), DestVT, N));
+  SDNodeFlags Flags;
+  Flags.copyFMF(*cast<FPMathOperator>(&I));
+  setValue(&I, DAG.getNode(ISD::SINT_TO_FP, getCurSDLoc(), DestVT, N, Flags));
 }
 
 void SelectionDAGBuilder::visitPtrToAddr(const User &I) {

>From cb1e76be816954de46365ec41dd1604ae641440b Mon Sep 17 00:00:00 2001
From: PaperChalice <liujunchang97 at outlook.com>
Date: Thu, 4 Jun 2026 17:02:58 +0800
Subject: [PATCH 2/2] [SelectionDAG] Remove NoSignedZerosFPMath uses

---
 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 530ba5f49824e..5bda6af7af07a 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -19951,8 +19951,7 @@ static SDValue foldFPToIntToFP(SDNode *N, const SDLoc &DL, SelectionDAG &DAG,
   bool IsSigned = N->getOpcode() == ISD::SINT_TO_FP;
   assert(IsSigned || IsUnsigned);
 
-  bool IsSignedZeroSafe = DAG.getTarget().Options.NoSignedZerosFPMath ||
-                          DAG.canIgnoreSignBitOfZero(SDValue(N, 0));
+  bool IsSignedZeroSafe = DAG.canIgnoreSignBitOfZero(SDValue(N, 0));
   // For signed conversions: The optimization changes signed zero behavior.
   if (IsSigned && !IsSignedZeroSafe)
     return SDValue();