[llvm] 1f2cfc4 - [BasicAliasAnalysis] Remove isMallocOrCallocLikeFn

[Bryce Wilson via llvm-commits]

Author: Bryce Wilson
Date: 2022-01-14T12:22:01-08:00
New Revision: 1f2cfc4fdc1eefb2c5f562c77a5fe7e916bbf670

URL: https://github.com/llvm/llvm-project/commit/1f2cfc4fdc1eefb2c5f562c77a5fe7e916bbf670
DIFF: https://github.com/llvm/llvm-project/commit/1f2cfc4fdc1eefb2c5f562c77a5fe7e916bbf670.diff

LOG: [BasicAliasAnalysis] Remove isMallocOrCallocLikeFn

Allocation functions should be marked with onlyAccessesInaccessibleMemory (when that is correct for the given function) which is checked elsewhere so this check is no longer needed.

Differential Revision: https://reviews.llvm.org/D117180

Added: 
    

Modified: 
    llvm/lib/Analysis/BasicAliasAnalysis.cpp
    llvm/test/Transforms/GVN/nonescaping-malloc.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Analysis/BasicAliasAnalysis.cpp b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
index fa9ccb095a21d..9485565bb57b7 100644
--- a/llvm/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
@@ -996,20 +996,6 @@ ModRefInfo BasicAAResult::getModRefInfo(const CallBase *Call,
     }
   }
 
-  // If the call is malloc/calloc like, we can assume that it doesn't
-  // modify any IR visible value.  This is only valid because we assume these
-  // routines do not read values visible in the IR.  TODO: Consider special
-  // casing realloc and strdup routines which access only their arguments as
-  // well.  Or alternatively, replace all of this with inaccessiblememonly once
-  // that's implemented fully.
-  if (isMallocOrCallocLikeFn(Call, &TLI)) {
-    // Be conservative if the accessed pointer may alias the allocation -
-    // fallback to the generic handling below.
-    if (getBestAAResults().alias(MemoryLocation::getBeforeOrAfter(Call), Loc,
-                                 AAQI) == AliasResult::NoAlias)
-      return ModRefInfo::NoModRef;
-  }
-
   // The semantics of memcpy intrinsics either exactly overlap or do not
   // overlap, i.e., source and destination of any given memcpy are either
   // no-alias or must-alias.

diff  --git a/llvm/test/Transforms/GVN/nonescaping-malloc.ll b/llvm/test/Transforms/GVN/nonescaping-malloc.ll
index fd61835e14a40..9eaf54c7a3d6c 100644
--- a/llvm/test/Transforms/GVN/nonescaping-malloc.ll
+++ b/llvm/test/Transforms/GVN/nonescaping-malloc.ll
@@ -35,7 +35,7 @@ entry:
 
 declare i64 @strlen(i8* nocapture) nounwind readonly
 
-declare noalias i8* @malloc(i64) nounwind
+declare noalias i8* @malloc(i64) nounwind inaccessiblememonly
 
 declare i32 @_ZN4llvm13StringMapImpl15LookupBucketForENS_9StringRefE(%"struct.llvm::StringMapImpl"*, i64, i64)
 
@@ -66,7 +66,7 @@ bb4.i:                                            ; preds = %entry
   %tmp4.i.i = sub i32 %tmp1.i.i, %tmp3.i.i
   %tmp5.i.i = add i32 %tmp4.i.i, 17
   %tmp8.i.i = zext i32 %tmp5.i.i to i64
-  %tmp.i20.i.i = tail call noalias i8* @malloc(i64 %tmp8.i.i) nounwind
+  %tmp.i20.i.i = tail call noalias i8* @malloc(i64 %tmp8.i.i) nounwind inaccessiblememonly
   %tmp10.i.i = bitcast i8* %tmp.i20.i.i to %"struct.llvm::StringMapEntry<void*>"*
   %tmp12.i.i = icmp eq i8* %tmp.i20.i.i, null
   br i1 %tmp12.i.i, label %_ZN4llvm14StringMapEntryIPvE6CreateINS_15MallocAllocatorES1_EEPS2_PKcS7_RT_T0_.exit.i, label %bb.i.i