Utilize correct tbaa when emitting stores of unions. (#54222)

Also remove unused argument from union_store

(cherry picked from commit 37f848c)

Author: gbaraldi

src/cgutils.cpp

@@ -3625,7 +3625,7 @@ static void emit_write_multibarrier(jl_codectx_t &ctx, Value *parent, Value *agg
 
 static jl_cgval_t union_store(jl_codectx_t &ctx,
         Value *ptr, Value *ptindex, jl_cgval_t rhs, jl_cgval_t cmp,
-        jl_value_t *jltype, MDNode *tbaa, MDNode *aliasscope, MDNode *tbaa_tindex,
+        jl_value_t *jltype, MDNode *tbaa, MDNode *tbaa_tindex,
         AtomicOrdering Order, AtomicOrdering FailOrder,
         Value *needlock, bool issetfield, bool isreplacefield, bool isswapfield, bool ismodifyfield, bool issetfieldonce,
         const jl_cgval_t *modifyop, const Twine &fname)
@@ -3683,7 +3683,7 @@ static jl_cgval_t union_store(jl_codectx_t &ctx,
     }
     Value *tindex = compute_tindex_unboxed(ctx, rhs_union, jltype);
     tindex = ctx.builder.CreateNUWSub(tindex, ConstantInt::get(getInt8Ty(ctx.builder.getContext()), 1));
-    jl_aliasinfo_t ai = jl_aliasinfo_t::fromTBAA(ctx, ctx.tbaa().tbaa_unionselbyte);
+    jl_aliasinfo_t ai = jl_aliasinfo_t::fromTBAA(ctx, tbaa_tindex);
     ai.decorateInst(ctx.builder.CreateAlignedStore(tindex, ptindex, Align(1)));
     // copy data
     if (!rhs.isghost) {
@@ -3739,7 +3739,7 @@ static jl_cgval_t emit_setfield(jl_codectx_t &ctx,
                 emit_bitcast(ctx, addr, getInt8PtrTy(ctx.builder.getContext())),
                 ConstantInt::get(ctx.types().T_size, fsz1));
         setNameWithField(ctx.emission_context, ptindex, get_objname, sty, idx0, Twine(".tindex_ptr"));
-        return union_store(ctx, addr, ptindex, rhs, cmp, jfty, tbaa, nullptr, ctx.tbaa().tbaa_unionselbyte,
+        return union_store(ctx, addr, ptindex, rhs, cmp, jfty, tbaa, ctx.tbaa().tbaa_unionselbyte,
             Order, FailOrder,
             needlock, issetfield, isreplacefield, isswapfield, ismodifyfield, issetfieldonce,
             modifyop, fname);

src/codegen.cpp

@@ -3870,7 +3870,7 @@ static bool emit_f_opmemory(jl_codectx_t &ctx, jl_cgval_t *ret, jl_value_t *f,
         ptindex = emit_bitcast(ctx, ptindex, getInt8PtrTy(ctx.builder.getContext()));
         ptindex = ctx.builder.CreateInBoundsGEP(getInt8Ty(ctx.builder.getContext()), ptindex, idx0);
         *ret = union_store(ctx, data, ptindex, val, cmp, ety,
-            ctx.tbaa().tbaa_arraybuf, nullptr, ctx.tbaa().tbaa_arrayselbyte,
+            ctx.tbaa().tbaa_arraybuf, ctx.tbaa().tbaa_arrayselbyte,
             Order, FailOrder,
             nullptr, issetmemory, isreplacememory, isswapmemory, ismodifymemory, issetmemoryonce,
             modifyop, fname);

test/compiler/codegen.jl

@@ -873,3 +873,17 @@ if Sys.ARCH === :x86_64
         end
     end
 end
+
+#Check if we aren't emitting the store with the wrong TBAA metadata
+
+foo54166(x,i,y) = x[i] = y
+let io = IOBuffer()
+    code_llvm(io,foo54166, (Vector{Union{Missing,Int}}, Int, Int), dump_module=true, raw=true)
+    str = String(take!(io))
+    @test !occursin("jtbaa_unionselbyte", str)
+    @test occursin("jtbaa_arrayselbyte", str)
+end
+
+ex54166 = Union{Missing, Int64}[missing -2; missing -2];
+dims54166 = (1,2)
+@test (minimum(ex54166; dims=dims54166)[1] === missing)