[llvm] [AMDGPU] Allocate i1 argument to SGPRs (PR #72461)

[Matt Arsenault via llvm-commits]

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@@ -29,6 +29,38 @@
 
 using namespace llvm;
 
+static bool CC_AMDGPU_Custom_I1(unsigned ValNo, MVT ValVT, MVT LocVT,
+                                CCValAssign::LocInfo LocInfo,
+                                ISD::ArgFlagsTy ArgFlags, CCState &State) {
+  static bool IsWave64 =
+      State.getMachineFunction().getSubtarget<GCNSubtarget>().isWave64();
+
+  static const MCPhysReg SGPRArgsWave64[] = {
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arsenm wrote:

We should maybe unroll the 64-bit case into unaligned 32-bit pieces, but it's going to complicate things. Probably best to leave that for a follow up patch later 

https://github.com/llvm/llvm-project/pull/72461