[llvm] [llvm][CodeGen] Update checking method of loop-carried phi in window scheduler (PR #96288)

[Hua Tian via llvm-commits]

=?utf-8?b?4oCcYWtpcmF0aWFu4oCd?= <akiratian at tencent.com>
Message-ID:
In-Reply-To: <llvm.org/llvm/llvm-project/pull/96288 at github.com>


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@@ -192,22 +192,36 @@ bool WindowScheduler::initialize() {
     return false;
   }
   // Check each MI in MBB.
-  SmallVector<Register, 8> PhiDefs;
+  SmallSet<Register, 8> PrevDefs;
+  SmallSet<Register, 8> PrevUses;
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huaatian wrote:

These sets are used to record the defs and uses of phis that have already been checked in the current MBB.  
They need to be initialized and retain register information across multiple calls to the lambda. 
Therefore,  wouldn't it be better to place these sets outside the lambda?

https://github.com/llvm/llvm-project/pull/96288