[llvm] 93d445c - [PostRASink] Add target hook shouldPostRASink (#167182)

[via llvm-commits]

Author: Junjie Gu
Date: 2025-11-09T00:18:43-08:00
New Revision: 93d445cba39f4dd3dcda4fa1433eca825cf8fc09

URL: https://github.com/llvm/llvm-project/commit/93d445cba39f4dd3dcda4fa1433eca825cf8fc09
DIFF: https://github.com/llvm/llvm-project/commit/93d445cba39f4dd3dcda4fa1433eca825cf8fc09.diff

LOG: [PostRASink] Add target hook shouldPostRASink (#167182)

Added: 
    

Modified: 
    llvm/include/llvm/CodeGen/TargetInstrInfo.h
    llvm/lib/CodeGen/MachineSink.cpp

Removed: 
    


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diff  --git a/llvm/include/llvm/CodeGen/TargetInstrInfo.h b/llvm/include/llvm/CodeGen/TargetInstrInfo.h
index 2dcedfb40f3e6..7010cffe23a11 100644
--- a/llvm/include/llvm/CodeGen/TargetInstrInfo.h
+++ b/llvm/include/llvm/CodeGen/TargetInstrInfo.h
@@ -436,7 +436,10 @@ class LLVM_ABI TargetInstrInfo : public MCInstrInfo {
   /// MachineSink determines on its own whether the instruction is safe to sink;
   /// this gives the target a hook to override the default behavior with regards
   /// to which instructions should be sunk.
+  ///
+  /// shouldPostRASink() is used by PostRAMachineSink.
   virtual bool shouldSink(const MachineInstr &MI) const { return true; }
+  virtual bool shouldPostRASink(const MachineInstr &MI) const { return true; }
 
   /// Return false if the instruction should not be hoisted by MachineLICM.
   ///

diff  --git a/llvm/lib/CodeGen/MachineSink.cpp b/llvm/lib/CodeGen/MachineSink.cpp
index cdcb29d92bfe6..94ed82eee9b8f 100644
--- a/llvm/lib/CodeGen/MachineSink.cpp
+++ b/llvm/lib/CodeGen/MachineSink.cpp
@@ -2287,6 +2287,10 @@ bool PostRAMachineSinkingImpl::tryToSinkCopy(MachineBasicBlock &CurBB,
       continue;
     }
 
+    // Don't postRASink instructions that the target prefers not to sink.
+    if (!TII->shouldPostRASink(MI))
+      continue;
+
     if (MI.isDebugOrPseudoInstr())
       continue;