[llvm-branch-commits] [llvm] AArch64: Use consistent atomicrmw expansion for FP operations (PR #103702)

[Eli Friedman via llvm-branch-commits]

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@@ -27056,21 +27056,35 @@ AArch64TargetLowering::shouldExpandAtomicLoadInIR(LoadInst *LI) const {
                              : AtomicExpansionKind::LLSC;
 }
 
+// Return true if the atomic operation expansion will lower to use a library
+// call, and is thus ineligible to use an LLSC expansion.
+static bool rmwOpMayLowerToLibcall(const AtomicRMWInst *RMW) {
+  if (!RMW->isFloatingPointOperation())
+    return false;
+  switch (RMW->getType()->getScalarType()->getTypeID()) {
+  case Type::FloatTyID:
+  case Type::DoubleTyID:
+  case Type::HalfTyID:
+  case Type::BFloatTyID:
+    return false;
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efriedma-quic wrote:

We need to check if we're in softfp mode (`Subtarget->hasFPARMv8()`).

https://github.com/llvm/llvm-project/pull/103702