Replace store of freeze in allocop and in emit new struct with memset…

… since aggregate stores are bad
JuliaLang · Sep 25, 2024 · 2cce1bd · 2cce1bd
1 parent 6e5e87b
commit 2cce1bd
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Showing 2 changed files with 6 additions and 11 deletions.
diff --git a/src/cgutils.cpp b/src/cgutils.cpp
@@ -4199,7 +4199,7 @@ static jl_cgval_t emit_new_struct(jl_codectx_t &ctx, jl_value_t *ty, size_t narg
                 else {
                     strct = UndefValue::get(lt);
                     if (nargs < nf)
-                        strct = ctx.builder.CreateFreeze(strct);
+                        strct = ctx.builder.CreateFreeze(strct); // Change this to zero initialize instead?
                 }
             }
             else if (tracked.second) {
@@ -4393,9 +4393,9 @@ static jl_cgval_t emit_new_struct(jl_codectx_t &ctx, jl_value_t *ty, size_t narg
                 if (promotion_point)
                     ctx.builder.SetInsertPoint(promotion_point);
                 if (strct) {
-                    promotion_point = cast<FreezeInst>(ctx.builder.CreateFreeze(UndefValue::get(lt)));
                     jl_aliasinfo_t ai = jl_aliasinfo_t::fromTBAA(ctx, ctx.tbaa().tbaa_stack);
-                    ai.decorateInst(ctx.builder.CreateStore(promotion_point, strct));
+                    ai.decorateInst(ctx.builder.CreateMemSet(strct, ConstantInt::get(getInt8Ty(ctx.builder.getContext()), 0),
+                                                                jl_datatype_size(ty), MaybeAlign(jl_datatype_align(ty))));
                 }
                 ctx.builder.restoreIP(savedIP);
             }

diff --git a/src/llvm-alloc-opt.cpp b/src/llvm-alloc-opt.cpp
@@ -622,14 +622,9 @@ void Optimizer::initializeAlloca(IRBuilder<> &prolog_builder, AllocaInst *buff,
         return;
     assert(!buff->isArrayAllocation());
     Type *T = buff->getAllocatedType();
-    Value *Init = UndefValue::get(T);
-    if ((allockind & AllocFnKind::Zeroed) != AllocFnKind::Unknown)
-        Init = Constant::getNullValue(T); // zero, as described
-    else if (allockind == AllocFnKind::Unknown)
-        Init = Constant::getNullValue(T); // assume zeroed since we didn't find the attribute
-    else
-        Init = prolog_builder.CreateFreeze(UndefValue::get(T)); // assume freeze, since LLVM does not natively support this case
-    prolog_builder.CreateStore(Init, buff);
+    const DataLayout &DL = F.getParent()->getDataLayout();
+    prolog_builder.CreateMemSet(buff, ConstantInt::get(Type::getInt8Ty(prolog_builder.getContext()), 0), DL.getTypeAllocSize(T), buff->getAlign());
+
 }
 
 // This function should not erase any safepoint so that the lifetime marker can find and cache