[llvm] [AMDGPU] Respect existing glue when lowering convergence tokens (PR #90834)

[Sameer Sahasrabuddhe via llvm-commits]

https://github.com/ssahasra updated https://github.com/llvm/llvm-project/pull/90834

>From 897cc6d48aa315c64a0f8bbd0878259cf2b34ed0 Mon Sep 17 00:00:00 2001
From: Sameer Sahasrabuddhe <sameer.sahasrabuddhe at amd.com>
Date: Mon, 6 May 2024 14:25:07 +0530
Subject: [PATCH] [AMDGPU] Respect existing glue when lowering convergence
 tokens

---
 llvm/lib/Target/AMDGPU/SIISelLowering.cpp | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
index ed41c10b50d323..3838631c6eac36 100644
--- a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
+++ b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
@@ -3860,20 +3860,20 @@ SDValue SITargetLowering::LowerCall(CallLoweringInfo &CLI,
   assert(Mask && "Missing call preserved mask for calling convention");
   Ops.push_back(DAG.getRegisterMask(Mask));
 
-  if (InGlue.getNode())
-    Ops.push_back(InGlue);
-
-  // NOTE: This potentially results in *two* glue operands, and the wrong one
-  // might possibly show up where the other was intended. In particular,
-  // Emitter::EmitMachineNode() expects only the glued convergence token if it
-  // exists. Similarly, the selection of the call expects to match only the
-  // InGlue operand if it exists.
   if (SDValue Token = CLI.ConvergenceControlToken) {
-    Ops.push_back(SDValue(DAG.getMachineNode(TargetOpcode::CONVERGENCECTRL_GLUE,
-                                             DL, MVT::Glue, Token),
-                          0));
+    SmallVector<SDValue, 2> GlueOps;
+    GlueOps.push_back(Token);
+    if (InGlue)
+      GlueOps.push_back(InGlue);
+
+    InGlue = SDValue(DAG.getMachineNode(TargetOpcode::CONVERGENCECTRL_GLUE, DL,
+                                        MVT::Glue, GlueOps),
+                     0);
   }
 
+  if (InGlue)
+    Ops.push_back(InGlue);
+
   SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Glue);
 
   // If we're doing a tall call, use a TC_RETURN here rather than an