[llvm] [AMDGPU][SIPreEmitPeephole] mustRetainExeczBranch: estimate ThenBlock cost using MachineTraceInfo (PR #111117)

[Christudasan Devadasan via llvm-commits]

Juan Manuel Martinez =?utf-8?q?Caamaño?= <juamarti at amd.com>,
Juan Manuel Martinez =?utf-8?q?Caamaño?= <juamarti at amd.com>
Message-ID:
In-Reply-To: <llvm.org/llvm/llvm-project/pull/111117 at github.com>


================
@@ -326,15 +345,32 @@ bool SIPreEmitPeephole::mustRetainExeczBranch(
       if (TII->hasUnwantedEffectsWhenEXECEmpty(MI))
         return true;
 
-      // These instructions are potentially expensive even if EXEC = 0.
-      if (TII->isSMRD(MI) || TII->isVMEM(MI) || TII->isFLAT(MI) ||
-          TII->isDS(MI) || TII->isWaitcnt(MI.getOpcode()))
-        return true;
-
-      ++NumInstr;
-      if (NumInstr >= SkipThreshold)
+      if (TII->isWaitcnt(MI.getOpcode()))
         return true;
     }
+
+    if (!MinInstr)
+      MinInstr = Traces->getEnsemble(MachineTraceStrategy::TS_Local);
----------------
cdevadas wrote:

@arsenm what do you mean by "Just initialize in pass setup?"
This looks right to me. Unlike other analyses, for MTM, the getAnalysis returns the MTM pass object and the actual analysis/computation to be done exactly when & where they are needed.

https://github.com/llvm/llvm-project/pull/111117