[llvm] [AMDGPU] Support partial and empty WWM pools for SGPR spills (PR #213491)

[Shilei Tian via llvm-commits]

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@@ -35,6 +35,11 @@ static cl::opt<bool>
     EnablePreallocateSGPRSpillVGPRs("amdgpu-prealloc-sgpr-spill-vgprs",
                                     cl::init(false), cl::Hidden);
 
+bool llvm::isPreallocateSGPRSpillVGPRsEnabled(const MachineFunction &MF) {
+  return EnablePreallocateSGPRSpillVGPRs ||
+         MF.getFunction().hasFnAttribute("amdgpu-prealloc-sgpr-spill-vgprs");
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shiltian wrote:

Well, interestingly, this attribute is not documented, nor actually consumed by the backend. I'll remove it.

https://github.com/llvm/llvm-project/pull/213491