From 18645d6f239a8d2e04f695df7f966f22991af35c Mon Sep 17 00:00:00 2001
From: Yangguang Li <yangguang.li1@huawei.com>
Date: Mon, 18 Aug 2025 17:37:10 +0800
Subject: [PATCH] [LoopDataPrefetch] Add unified option to control crc hash
 prefetch

---
 llvm/lib/Transforms/Scalar/LoopDataPrefetch.cpp | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/llvm/lib/Transforms/Scalar/LoopDataPrefetch.cpp b/llvm/lib/Transforms/Scalar/LoopDataPrefetch.cpp
index dde7de406c58..a8ff70d9fd64 100644
--- a/llvm/lib/Transforms/Scalar/LoopDataPrefetch.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopDataPrefetch.cpp
@@ -105,6 +105,11 @@ static cl::opt<unsigned>
                       cl::desc("Least loop depth to insert prefetch"),
                       cl::Hidden, cl::init(1));
 
+static cl::opt<bool>
+    EnableCrcHashPrefetch("enable-crc-hash-prefetch", cl::Hidden,
+                              cl::init(false),
+                              cl::desc("Enable crc hash load prefetch"));
+
 STATISTIC(NumPrefetches, "Number of prefetches inserted");
 STATISTIC(NumIndPrefetches, "Number of indirect prefetches inserted");
 STATISTIC(NumOuterLoopPrefetches, "Number of outer loop prefetches inserted");
@@ -551,7 +556,7 @@ bool LoopDataPrefetch::insertPrefetcherForIndirectLoad(
   Module *M = TargetIndirectLoad->getModule();
   Type *I32Ty = Type::getInt32Ty(TargetIndirectLoad->getParent()->getContext());
 
-  if (RandomAccessPrefetchOnly) {
+  if (RandomAccessPrefetchOnly || EnableCrcHashPrefetch) {
     bool isRandomAccess = false;
     for (auto *I : DependentInsts) {
       if (isCrcHashDataAccess(I, TargetIndirectLoad)) {
@@ -813,7 +818,7 @@ bool LoopDataPrefetch::findCandidateMemoryLoads(
         break;
       }
       case Instruction::Call: {
-        if (PrefetchInOuterLoop || RandomAccessPrefetchOnly) {
+        if (PrefetchInOuterLoop || RandomAccessPrefetchOnly || EnableCrcHashPrefetch) {
           if (OperandInst->mayReadOrWriteMemory())
             return false;
           CallInst *Call = dyn_cast<CallInst>(OperandInst);
@@ -1538,7 +1543,7 @@ bool LoopDataPrefetch::runOnLoop(Loop *L) {
   bool IsInnerMost = true;
   // Prefetch outer loop if needed.
   if (!L->isInnermost()) {
-    if (OuterLoopPrefetch)
+    if (OuterLoopPrefetch || EnableCrcHashPrefetch)
       IsInnerMost = false;
     else
       return MadeChange;
@@ -1666,7 +1671,7 @@ bool LoopDataPrefetch::runOnLoop(Loop *L) {
           }
         }
       }
-      if (!DupPref && !DisableDirectLoadPrefetch)
+      if (!DupPref && !(DisableDirectLoadPrefetch || EnableCrcHashPrefetch))
         Prefetches.push_back(Prefetch(LSCEVAddRec, MemI));
     }
   }
@@ -1727,7 +1732,7 @@ bool LoopDataPrefetch::runOnLoop(Loop *L) {
     MadeChange = true;
   }
 
-  if (!IndirectLoadPrefetch)
+  if (!IndirectLoadPrefetch && !EnableCrcHashPrefetch)
     return MadeChange;
 
   // List of valid phi nodes that indirect loads can depend on.
@@ -1758,7 +1763,7 @@ bool LoopDataPrefetch::runOnLoop(Loop *L) {
       return MadeChange;
   }
 
-  if (!RandomAccessPrefetchOnly && !PrefetchInOuterLoop &&
+  if (!EnableCrcHashPrefetch && !RandomAccessPrefetchOnly && !PrefetchInOuterLoop &&
       !canDoIndirectPrefetch(L)) {
     cleanLoopIterationNumber(NumIterations);
     return MadeChange;
-- 
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