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

[Matt Arsenault via llvm-commits]

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@@ -3479,6 +3484,22 @@ SDValue SITargetLowering::LowerCall(CallLoweringInfo &CLI,
     passSpecialInputs(CLI, CCInfo, *Info, RegsToPass, MemOpChains, Chain);
   }
 
+  // In code below (after call of AnalyzeCallOperands),
+  // if (!Subtarget->enableFlatScratch()), it would use either s[48:51] or
+  // s[0:3]. Therefore, before calling AnalyzeCallOperands, we may need to
+  // reserve these registers.
+  if (!Subtarget->enableFlatScratch()) {
+    if (IsChainCallConv)
+      CCInfo.AllocateRegBlock(
+          ArrayRef<MCPhysReg>{AMDGPU::SGPR48, AMDGPU::SGPR49, AMDGPU::SGPR50,
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arsenm wrote:

AllocateReg works if you pass the register tuple value. It iterates all aliases 

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