[llvm] [AArch64] Remove `UnsafeFPMath` (PR #150876)

[via llvm-commits]

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@@ -12292,7 +12290,8 @@ SDValue AArch64TargetLowering::getSqrtEstimate(SDValue Operand,
       SDLoc DL(Operand);
       EVT VT = Operand.getValueType();
 
-      SDNodeFlags Flags = SDNodeFlags::AllowReassociation;
+      SDNodeFlags Flags =
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paperchalice wrote:

Reassoc flag is not enough, aarch64 backend requires nsz to generate expected code, see the change in llvm/lib/Target/AArch64/AArch64InstrInfo.cpp. IMO extra nsz flag seems too strict here.
Will add related comment later. 

https://github.com/llvm/llvm-project/pull/150876