[llvm] [SDAG] Add missing ppc_fp128 ExpandFloatRes for sincos[pi] (PR #128514)

[Matt Arsenault via llvm-commits]

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@@ -49,3 +49,49 @@ define { ppc_fp128, ppc_fp128 } @test_sincospi_ppcf128(ppc_fp128 %a) {
   %result = call { ppc_fp128, ppc_fp128 } @llvm.sincospi.ppcf128(ppc_fp128 %a)
   ret { ppc_fp128, ppc_fp128 } %result
 }
+
+; FIXME: Recognise this as a tail call and omit the stack frame:
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arsenm wrote:

What do you mean by "what the codegen emits"? The issue is what is in the IR. This function should return the original { ppc_fp128, ppc_fp128 } with no extracts or stores 

https://github.com/llvm/llvm-project/pull/128514