[llvm] f45ab43 - [MemoryBuiltins] Avoid isAllocationFn() call before checking removable alloc

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2022-07-21T09:39:19+02:00
New Revision: f45ab433320fadf04aa90042337f1c2e509edb2c

URL: https://github.com/llvm/llvm-project/commit/f45ab433320fadf04aa90042337f1c2e509edb2c
DIFF: https://github.com/llvm/llvm-project/commit/f45ab433320fadf04aa90042337f1c2e509edb2c.diff

LOG: [MemoryBuiltins] Avoid isAllocationFn() call before checking removable alloc

Alloc directly checking whether a given call is a removable
allocation, instead of first checking whether it is an allocation
first.

Added: 
    

Modified: 
    llvm/include/llvm/Analysis/MemoryBuiltins.h
    llvm/lib/Analysis/MemoryBuiltins.cpp
    llvm/lib/Transforms/IPO/AttributorAttributes.cpp
    llvm/lib/Transforms/IPO/GlobalOpt.cpp
    llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
    llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
    llvm/lib/Transforms/Utils/Local.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/Analysis/MemoryBuiltins.h b/llvm/include/llvm/Analysis/MemoryBuiltins.h
index 7ad83612880f5..b0ff7f969484a 100644
--- a/llvm/include/llvm/Analysis/MemoryBuiltins.h
+++ b/llvm/include/llvm/Analysis/MemoryBuiltins.h
@@ -91,15 +91,16 @@ inline CallInst *isFreeCall(Value *I, const TargetLibraryInfo *TLI) {
 //  Properties of allocation functions
 //
 
-/// Return false if the allocation can have side effects on the program state
-/// we are required to preserve beyond the effect of allocating a new object.
+/// Return true if this is a call to an allocation function that does not have
+/// side effects that we are required to preserve beyond the effect of
+/// allocating a new object.
 /// Ex: If our allocation routine has a counter for the number of objects
 /// allocated, and the program prints it on exit, can the value change due
 /// to optimization? Answer is highly language dependent.
 /// Note: *Removable* really does mean removable; it does not mean observable.
 /// A language (e.g. C++) can allow removing allocations without allowing
 /// insertion or speculative execution of allocation routines.
-bool isAllocRemovable(const CallBase *V, const TargetLibraryInfo *TLI);
+bool isRemovableAlloc(const CallBase *V, const TargetLibraryInfo *TLI);
 
 /// Gets the alignment argument for an aligned_alloc-like function, using either
 /// built-in knowledge based on fuction names/signatures or allocalign

diff  --git a/llvm/lib/Analysis/MemoryBuiltins.cpp b/llvm/lib/Analysis/MemoryBuiltins.cpp
index f5b121c98ec48..5c9f9cc94fd1e 100644
--- a/llvm/lib/Analysis/MemoryBuiltins.cpp
+++ b/llvm/lib/Analysis/MemoryBuiltins.cpp
@@ -319,15 +319,14 @@ bool llvm::isReallocLikeFn(const Function *F, const TargetLibraryInfo *TLI) {
   return getAllocationDataForFunction(F, ReallocLike, TLI).has_value();
 }
 
-bool llvm::isAllocRemovable(const CallBase *CB, const TargetLibraryInfo *TLI) {
-  assert(isAllocationFn(CB, TLI));
-
+bool llvm::isRemovableAlloc(const CallBase *CB, const TargetLibraryInfo *TLI) {
   // Note: Removability is highly dependent on the source language.  For
   // example, recent C++ requires direct calls to the global allocation
   // [basic.stc.dynamic.allocation] to be observable unless part of a new
   // expression [expr.new paragraph 13].
 
-  // Historically we've treated the C family allocation routines as removable
+  // Historically we've treated the C family allocation routines and operator
+  // new as removable
   return isAllocLikeFn(CB, TLI);
 }
 

diff  --git a/llvm/lib/Transforms/IPO/AttributorAttributes.cpp b/llvm/lib/Transforms/IPO/AttributorAttributes.cpp
index 501b902812827..af515c9fe34a1 100644
--- a/llvm/lib/Transforms/IPO/AttributorAttributes.cpp
+++ b/llvm/lib/Transforms/IPO/AttributorAttributes.cpp
@@ -5836,7 +5836,7 @@ struct AAHeapToStackFunction final : public AAHeapToStack {
       // To do heap to stack, we need to know that the allocation itself is
       // removable once uses are rewritten, and that we can initialize the
       // alloca to the same pattern as the original allocation result.
-      if (isAllocationFn(CB, TLI) && isAllocRemovable(CB, TLI)) {
+      if (isRemovableAlloc(CB, TLI)) {
         auto *I8Ty = Type::getInt8Ty(CB->getParent()->getContext());
         if (nullptr != getInitialValueOfAllocation(CB, TLI, I8Ty)) {
           AllocationInfo *AI = new (A.Allocator) AllocationInfo{CB};

diff  --git a/llvm/lib/Transforms/IPO/GlobalOpt.cpp b/llvm/lib/Transforms/IPO/GlobalOpt.cpp
index 1ad6e2b2a1d24..ec26db8bfc0b4 100644
--- a/llvm/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/llvm/lib/Transforms/IPO/GlobalOpt.cpp
@@ -1040,7 +1040,7 @@ static bool tryToOptimizeStoreOfAllocationToGlobal(GlobalVariable *GV,
                                                    CallInst *CI,
                                                    const DataLayout &DL,
                                                    TargetLibraryInfo *TLI) {
-  if (!isAllocRemovable(CI, TLI))
+  if (!isRemovableAlloc(CI, TLI))
     // Must be able to remove the call when we get done..
     return false;
 

diff  --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 741725d226623..6a2cfd63573a4 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -3079,8 +3079,7 @@ Instruction *InstCombinerImpl::visitCallBase(CallBase &Call) {
             Call, Builder.CreateBitOrPointerCast(ReturnedArg, CallTy));
     }
 
-  if (isAllocationFn(&Call, &TLI) &&
-      isAllocRemovable(&cast<CallBase>(Call), &TLI))
+  if (isRemovableAlloc(&Call, &TLI))
     return visitAllocSite(Call);
 
   // Handle intrinsics which can be used in both call and invoke context.

diff  --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index 42c6433270db0..98292c49e714c 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -2832,7 +2832,7 @@ static bool isAllocSiteRemovable(Instruction *AI,
 }
 
 Instruction *InstCombinerImpl::visitAllocSite(Instruction &MI) {
-  assert(isa<AllocaInst>(MI) || isAllocRemovable(&cast<CallBase>(MI), &TLI));
+  assert(isa<AllocaInst>(MI) || isRemovableAlloc(&cast<CallBase>(MI), &TLI));
 
   // If we have a malloc call which is only used in any amount of comparisons to
   // null and free calls, delete the calls and replace the comparisons with true

diff  --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index 9b1bb93b29153..83e67b108ed9f 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -439,8 +439,9 @@ bool llvm::wouldInstructionBeTriviallyDead(Instruction *I,
     return true;
   }
 
-  if (isAllocationFn(I, TLI) && isAllocRemovable(cast<CallBase>(I), TLI))
-    return true;
+  if (auto *CB = dyn_cast<CallBase>(I))
+    if (isRemovableAlloc(CB, TLI))
+      return true;
 
   if (!I->willReturn())
     return false;