[llvm] [llvm][AMDGPU] Implemented isProfitableToHoist and isFMAFasterThanFMulAndFAdd (PR #108756)

[Matt Arsenault via llvm-commits]

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@@ -891,6 +891,37 @@ bool AMDGPUTargetLowering::isCheapToSpeculateCtlz(Type *Ty) const {
   return true;
 }
 
+bool AMDGPUTargetLowering::isFMAFasterThanFMulAndFAdd(const MachineFunction &MF,
+                                                      EVT VT) const {
+  VT = VT.getScalarType();
+
+  if (!VT.isSimple())
+    return false;
+
+  switch (VT.getSimpleVT().SimpleTy) {
+  case MVT::f16:
+    return Subtarget->hasFullFP16();
+  case MVT::f32:
+  case MVT::f64:
+    return true;
+  default:
+    break;
+  }
+
+  return false;
+}
+
+bool AMDGPUTargetLowering::isFMAFasterThanFMulAndFAdd(const Function &F,
+                                                      Type *Ty) const {
+  switch (Ty->getScalarType()->getTypeID()) {
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arsenm wrote:

This should have the same logic as the EVT variant, this is the aarch64 logic 

https://github.com/llvm/llvm-project/pull/108756