[PATCH] D152430: [DAG] Peek through freeze when deciding whether we should convert setcc to math or not.

[Amaury SECHET via Phabricator via llvm-commits]

deadalnix created this revision.
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Because later tranform push the freeze through the setcc, we end up having to reconstruct the setcc, which can cause infinite loops.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D152430

Files:
  llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp


Index: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -12230,8 +12230,18 @@
   // setcc is very commonly used as an argument to brcond. This pattern
   // also lend itself to numerous combines and, as a result, it is desired
   // we keep the argument to a brcond as a setcc as much as possible.
-  bool PreferSetCC =
-      N->hasOneUse() && N->use_begin()->getOpcode() == ISD::BRCOND;
+  bool PreferSetCC = [&]() {
+    if (!N->hasOneUse()) {
+      return false;
+    }
+
+    SDNode *U = *N->use_begin();
+    if (U->getOpcode() == ISD::FREEZE && U->hasOneUse()) {
+      U = *U->use_begin();
+    }
+
+    return U->getOpcode() == ISD::BRCOND;
+  }();
 
   ISD::CondCode Cond = cast<CondCodeSDNode>(N->getOperand(2))->get();
   EVT VT = N->getValueType(0);


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