[llvm] [AMDGPU] Add option to pre-allocate SGPR spill VGPRs (PR #70626)

[Christudasan Devadasan via llvm-commits]

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@@ -201,6 +205,10 @@ bool SIPreAllocateWWMRegs::runOnMachineFunction(MachineFunction &MF) {
 
   RegClassInfo.runOnMachineFunction(MF);
 
+  bool PreallocateSGPRSpillVGPRs =
+      EnablePreallocateSGPRSpillVGPRs ||
+      MF.getFunction().hasFnAttribute("amdgpu-prealloc-sgpr-spill-vgprs");
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cdevadas wrote:

For shaders, I hope the SGPR spills are very limited and they won't require more VGPRs causing the 'ran out of allocatable registers' error.

https://github.com/llvm/llvm-project/pull/70626