[PATCH] D95356: NFC: Migrate SpeculativeExecution to work on InstructionCost

[Sander de Smalen via Phabricator via llvm-commits]

sdesmalen created this revision.
sdesmalen added reviewers: ctetreau, david-arm.
Herald added a subscriber: hiraditya.
sdesmalen requested review of this revision.
Herald added a project: LLVM.

This patch migrates cost values and arithmetic to work on InstructionCost.
When the interfaces to TargetTransformInfo are changed, any InstructionCost
state will propagate naturally.

See this patch for the introduction of the type: https://reviews.llvm.org/D91174
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2020-November/146408.html


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D95356

Files:
  llvm/lib/Transforms/Scalar/SpeculativeExecution.cpp


Index: llvm/lib/Transforms/Scalar/SpeculativeExecution.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/SpeculativeExecution.cpp
+++ llvm/lib/Transforms/Scalar/SpeculativeExecution.cpp
@@ -210,8 +210,8 @@
   return false;
 }
 
-static unsigned ComputeSpeculationCost(const Instruction *I,
-                                       const TargetTransformInfo &TTI) {
+static InstructionCost ComputeSpeculationCost(const Instruction *I,
+                                              const TargetTransformInfo &TTI) {
   switch (Operator::getOpcode(I)) {
     case Instruction::GetElementPtr:
     case Instruction::Add:
@@ -255,7 +255,8 @@
       return TTI.getUserCost(I, TargetTransformInfo::TCK_SizeAndLatency);
 
     default:
-      return UINT_MAX; // Disallow anything not explicitly listed.
+      return InstructionCost::getInvalid(); // Disallow anything not explicitly
+                                            // listed.
   }
 }
 
@@ -288,11 +289,11 @@
     return true;
   };
 
-  unsigned TotalSpeculationCost = 0;
+  InstructionCost TotalSpeculationCost = 0;
   unsigned NotHoistedInstCount = 0;
   for (const auto &I : FromBlock) {
-    const unsigned Cost = ComputeSpeculationCost(&I, *TTI);
-    if (Cost != UINT_MAX && isSafeToSpeculativelyExecute(&I) &&
+    const InstructionCost Cost = ComputeSpeculationCost(&I, *TTI);
+    if (Cost.isValid() && isSafeToSpeculativelyExecute(&I) &&
         AllPrecedingUsesFromBlockHoisted(&I)) {
       TotalSpeculationCost += Cost;
       if (TotalSpeculationCost > SpecExecMaxSpeculationCost)


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