[llvm] [PPC]Optimize zeroing accumulator and spilling instructions into simple instructions (PR #96094)

[Chen Zheng via llvm-commits]

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@@ -109,6 +109,93 @@ static bool hasPCRelativeForm(MachineInstr &Use) {
           MachineFunctionProperties::Property::NoVRegs);
     }
 
+    // The funtion will simply the zeroing accumulator and spilling instrcutions
+    // into simple xxlxor and spilling instrcuctions.
+    // From:
+    // setaccz acci
+    // xxmfacc acci
+    // stxv vsr(i*4+0), D(1)
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chenzheng1030 wrote:

What does `D(1)` mean? 1 is for R1? could we use another name like `Base`? And we don't check the offsets in the implementation, so maybe the D/D-16/D-32/D-48 is also not necessary?

https://github.com/llvm/llvm-project/pull/96094