[llvm] [AMDGPU] Extend wave reduce intrinsics for i32 type (PR #126469)

[Matt Arsenault via llvm-commits]

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@@ -4955,13 +4977,78 @@ static MachineBasicBlock *lowerWaveReduce(MachineInstr &MI,
   Register DstReg = MI.getOperand(0).getReg();
   MachineBasicBlock *RetBB = nullptr;
   if (isSGPR) {
-    // These operations with a uniform value i.e. SGPR are idempotent.
-    // Reduced value will be same as given sgpr.
-    // clang-format off
-    BuildMI(BB, MI, DL, TII->get(AMDGPU::S_MOV_B32), DstReg)
-        .addReg(SrcReg);
-    // clang-format on
-    RetBB = &BB;
+    switch (Opc) {
+    case AMDGPU::S_MIN_U32:
+    case AMDGPU::S_MIN_I32:
+    case AMDGPU::S_MAX_U32:
+    case AMDGPU::S_MAX_I32:
+    case AMDGPU::S_AND_B32:
+    case AMDGPU::S_OR_B32: {
+      // Idempotent operations.
+      BuildMI(BB, MI, DL, TII->get(AMDGPU::S_MOV_B32), DstReg).addReg(SrcReg);
+      RetBB = &BB;
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arsenm wrote:

I don't really follow what RetBB is for, it's always identical to BB?

https://github.com/llvm/llvm-project/pull/126469