[llvm] 9d20eaf - [BasicAA] Don't store AATags in cache key (NFC)

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2021-04-03T11:32:01+02:00
New Revision: 9d20eaf9c08c9c22aa0d13f04d8e7895c9ac05d4

URL: https://github.com/llvm/llvm-project/commit/9d20eaf9c08c9c22aa0d13f04d8e7895c9ac05d4
DIFF: https://github.com/llvm/llvm-project/commit/9d20eaf9c08c9c22aa0d13f04d8e7895c9ac05d4.diff

LOG: [BasicAA] Don't store AATags in cache key (NFC)

The AAMDNodes part of the MemoryLocation is not used by the BasicAA
cache, so don't store it. This reduces the size of each cache entry
from 112 bytes to 48 bytes.

Added: 
    

Modified: 
    llvm/include/llvm/Analysis/AliasAnalysis.h
    llvm/lib/Analysis/BasicAliasAnalysis.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/Analysis/AliasAnalysis.h b/llvm/include/llvm/Analysis/AliasAnalysis.h
index 3910966fda7b..66ff5c058465 100644
--- a/llvm/include/llvm/Analysis/AliasAnalysis.h
+++ b/llvm/include/llvm/Analysis/AliasAnalysis.h
@@ -335,6 +335,31 @@ createModRefInfo(const FunctionModRefBehavior FMRB) {
   return ModRefInfo(FMRB & static_cast<int>(ModRefInfo::ModRef));
 }
 
+/// Reduced version of MemoryLocation that only stores a pointer and size.
+/// Used for caching AATags independent BasicAA results.
+struct AACacheLoc {
+  const Value *Ptr;
+  LocationSize Size;
+};
+
+template <> struct DenseMapInfo<AACacheLoc> {
+  static inline AACacheLoc getEmptyKey() {
+    return {DenseMapInfo<const Value *>::getEmptyKey(),
+            DenseMapInfo<LocationSize>::getEmptyKey()};
+  }
+  static inline AACacheLoc getTombstoneKey() {
+    return {DenseMapInfo<const Value *>::getTombstoneKey(),
+            DenseMapInfo<LocationSize>::getTombstoneKey()};
+  }
+  static unsigned getHashValue(const AACacheLoc &Val) {
+    return DenseMapInfo<const Value *>::getHashValue(Val.Ptr) ^
+           DenseMapInfo<LocationSize>::getHashValue(Val.Size);
+  }
+  static bool isEqual(const AACacheLoc &LHS, const AACacheLoc &RHS) {
+    return LHS.Ptr == RHS.Ptr && LHS.Size == RHS.Size;
+  }
+};
+
 /// This class stores info we want to provide to or retain within an alias
 /// query. By default, the root query is stateless and starts with a freshly
 /// constructed info object. Specific alias analyses can use this query info to
@@ -355,7 +380,7 @@ class AAQueryInfo {
       ClobberOffsets;
 
 public:
-  using LocPair = std::pair<MemoryLocation, MemoryLocation>;
+  using LocPair = std::pair<AACacheLoc, AACacheLoc>;
   struct CacheEntry {
     AliasResult Result;
     /// Number of times a NoAlias assumption has been used.

diff  --git a/llvm/lib/Analysis/BasicAliasAnalysis.cpp b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
index 5b5b85886d02..26157b232128 100644
--- a/llvm/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
@@ -1529,8 +1529,7 @@ AliasResult BasicAAResult::aliasCheck(const Value *V1, LocationSize V1Size,
 
   // Check the cache before climbing up use-def chains. This also terminates
   // otherwise infinitely recursive queries.
-  AAQueryInfo::LocPair Locs(MemoryLocation(V1, V1Size),
-                            MemoryLocation(V2, V2Size));
+  AAQueryInfo::LocPair Locs({V1, V1Size}, {V2, V2Size});
   if (V1 > V2)
     std::swap(Locs.first, Locs.second);
   const auto &Pair = AAQI.AliasCache.try_emplace(