[PATCH] D87490: [MachineInstr] return mayAlias for not mayLoadOrStore instructions.

[ChenZheng via Phabricator via llvm-commits]

shchenz created this revision.
shchenz added reviewers: Kayjukh, efriedma, qcolombet, hfinkel.
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This is a typo fix for `bool MachineInstr::mayAlias()` function.

We should not call this function for not `mayLoadOrStore` instructions. But Iif we do so by mistake, we should return conservative value.

For example:
For now `mayAlias(CallInstruction, LoadInstruction)` always returns `false` (NoAlias), this is not right. `CallInstruction` may alert the memory where the LoadInstruction operates on.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D87490

Files:
  llvm/lib/CodeGen/MachineInstr.cpp


Index: llvm/lib/CodeGen/MachineInstr.cpp
===================================================================
--- llvm/lib/CodeGen/MachineInstr.cpp
+++ llvm/lib/CodeGen/MachineInstr.cpp
@@ -1241,7 +1241,7 @@
 
   // Both instructions must be memory operations to be able to alias.
   if (!mayLoadOrStore() || !Other.mayLoadOrStore())
-    return false;
+    return true;
 
   // Let the target decide if memory accesses cannot possibly overlap.
   if (TII->areMemAccessesTriviallyDisjoint(*this, Other))


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