[llvm] WIP [GlobalISel] Remove `UnsafeFP` references (PR #146319)

[via llvm-commits]

https://github.com/paperchalice created https://github.com/llvm/llvm-project/pull/146319

None

>From c853747e81efb42c5612de2ab59cb57878ee2233 Mon Sep 17 00:00:00 2001
From: PaperChalice <liujunchang97 at outlook.com>
Date: Mon, 30 Jun 2025 16:45:22 +0800
Subject: [PATCH] Remove `UnsafeFP` references

---
 llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp  | 6 ++----
 llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp | 2 +-
 2 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
index 05dd269d48921..f50bbe57a7e5c 100644
--- a/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
@@ -5830,8 +5830,7 @@ bool CombinerHelper::canCombineFMadOrFMA(MachineInstr &MI,
   const TargetOptions &Options = MF->getTarget().Options;
   LLT DstType = MRI.getType(MI.getOperand(0).getReg());
 
-  if (CanReassociate &&
-      !(Options.UnsafeFPMath || MI.getFlag(MachineInstr::MIFlag::FmReassoc)))
+  if (CanReassociate && !MI.getFlag(MachineInstr::MIFlag::FmReassoc))
     return false;
 
   // Floating-point multiply-add with intermediate rounding.
@@ -5843,8 +5842,7 @@ bool CombinerHelper::canCombineFMadOrFMA(MachineInstr &MI,
   if (!HasFMAD && !HasFMA)
     return false;
 
-  AllowFusionGlobally = Options.AllowFPOpFusion == FPOpFusion::Fast ||
-                        Options.UnsafeFPMath || HasFMAD;
+  AllowFusionGlobally = Options.AllowFPOpFusion == FPOpFusion::Fast || HasFMAD;
   // If the addition is not contractable, do not combine.
   if (!AllowFusionGlobally && !MI.getFlag(MachineInstr::MIFlag::FmContract))
     return false;
diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index b87b029d01632..118d83883e9f2 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -7982,7 +7982,7 @@ LegalizerHelper::lowerFPTRUNC_F64_TO_F16(MachineInstr &MI) {
   if (MRI.getType(Src).isVector()) // TODO: Handle vectors directly.
     return UnableToLegalize;
 
-  if (MIRBuilder.getMF().getTarget().Options.UnsafeFPMath) {
+  if (MI.getFlag(MachineInstr::FmAfn)) {
     unsigned Flags = MI.getFlags();
     auto Src32 = MIRBuilder.buildFPTrunc(S32, Src, Flags);
     MIRBuilder.buildFPTrunc(Dst, Src32, Flags);