[PATCH] D120295: [SampleProfile] Handle the case when the option `MaxNumPromotions` is zero.

[Mingming Liu via Phabricator via llvm-commits]

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In places where `MaxNumPromotions` is used to allocated an array, bail out early to prevent allocating an array of length 0.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D120295

Files:
  llvm/lib/Transforms/IPO/SampleProfile.cpp


Index: llvm/lib/Transforms/IPO/SampleProfile.cpp
===================================================================
--- llvm/lib/Transforms/IPO/SampleProfile.cpp
+++ llvm/lib/Transforms/IPO/SampleProfile.cpp
@@ -802,6 +802,11 @@
 /// NOMORE_ICP_MAGICNUM count values in the value profile of \p Inst, we
 /// cannot promote for \p Inst anymore.
 static bool doesHistoryAllowICP(const Instruction &Inst, StringRef Candidate) {
+  // Bail out early if MaxNumPromotions is zero.
+  // This prevents allocating an array of zero length below.
+  if (MaxNumPromotions == 0)
+    return false;
+
   uint32_t NumVals = 0;
   uint64_t TotalCount = 0;
   std::unique_ptr<InstrProfValueData[]> ValueData =
@@ -841,6 +846,11 @@
 updateIDTMetaData(Instruction &Inst,
                   const SmallVectorImpl<InstrProfValueData> &CallTargets,
                   uint64_t Sum) {
+  // Bail out early if MaxNumPromotions is zero.
+  // This prevents allocating an array of zero length below.
+  if (MaxNumPromotions == 0)
+    return;
+
   uint32_t NumVals = 0;
   // OldSum is the existing total count in the value profile data.
   uint64_t OldSum = 0;


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