codegen: fix bits compare for UnionAll (JuliaLang#55770)

Fixes JuliaLang#55768 in two parts: one is making the type computation in
emit_bits_compare agree with the parent function and two is not using
the optimized egal code for UnionAll kinds, which is different from how
the egal code itself works for kinds.

src/codegen.cpp

@@ -3484,25 +3484,26 @@ static size_t emit_masked_bits_compare(callback &emit_desc, jl_datatype_t *aty,
 static Value *emit_bits_compare(jl_codectx_t &ctx, jl_cgval_t arg1, jl_cgval_t arg2)
 {
     ++EmittedBitsCompares;
+    jl_value_t *argty = (arg1.constant ? jl_typeof(arg1.constant) : arg1.typ);
     bool isboxed;
     Type *at = julia_type_to_llvm(ctx, arg1.typ, &isboxed);
-    assert(jl_is_datatype(arg1.typ) && arg1.typ == arg2.typ && !isboxed);
+    assert(jl_is_datatype(arg1.typ) && arg1.typ == (arg2.constant ? jl_typeof(arg2.constant) : arg2.typ) && !isboxed);
 
     if (type_is_ghost(at))
         return ConstantInt::get(getInt1Ty(ctx.builder.getContext()), 1);
 
     if (at->isIntegerTy() || at->isPointerTy() || at->isFloatingPointTy()) {
         Type *at_int = INTT(at, ctx.emission_context.DL);
-        Value *varg1 = emit_unbox(ctx, at_int, arg1, arg1.typ);
-        Value *varg2 = emit_unbox(ctx, at_int, arg2, arg2.typ);
+        Value *varg1 = emit_unbox(ctx, at_int, arg1, argty);
+        Value *varg2 = emit_unbox(ctx, at_int, arg2, argty);
         return ctx.builder.CreateICmpEQ(varg1, varg2);
     }
 
     if (at->isVectorTy()) {
-        jl_svec_t *types = ((jl_datatype_t*)arg1.typ)->types;
+        jl_svec_t *types = ((jl_datatype_t*)argty)->types;
         Value *answer = ConstantInt::get(getInt1Ty(ctx.builder.getContext()), 1);
-        Value *varg1 = emit_unbox(ctx, at, arg1, arg1.typ);
-        Value *varg2 = emit_unbox(ctx, at, arg2, arg2.typ);
+        Value *varg1 = emit_unbox(ctx, at, arg1, argty);
+        Value *varg2 = emit_unbox(ctx, at, arg2, argty);
         for (size_t i = 0, l = jl_svec_len(types); i < l; i++) {
             jl_value_t *fldty = jl_svecref(types, i);
             Value *subAns, *fld1, *fld2;
@@ -3517,7 +3518,7 @@ static Value *emit_bits_compare(jl_codectx_t &ctx, jl_cgval_t arg1, jl_cgval_t a
     }
 
     if (at->isAggregateType()) { // Struct or Array
-        jl_datatype_t *sty = (jl_datatype_t*)arg1.typ;
+        jl_datatype_t *sty = (jl_datatype_t*)argty;
         size_t sz = jl_datatype_size(sty);
         if (sz > 512 && !sty->layout->flags.haspadding && sty->layout->flags.isbitsegal) {
             Value *varg1 = arg1.ispointer() ? data_pointer(ctx, arg1) :
@@ -3721,8 +3722,10 @@ static Value *emit_f_is(jl_codectx_t &ctx, const jl_cgval_t &arg1, const jl_cgva
     if (jl_type_intersection(rt1, rt2) == (jl_value_t*)jl_bottom_type) // types are disjoint (exhaustive test)
         return ConstantInt::get(getInt1Ty(ctx.builder.getContext()), 0);
 
-    bool justbits1 = jl_is_concrete_immutable(rt1);
-    bool justbits2 = jl_is_concrete_immutable(rt2);
+    // can compare any concrete immutable by bits, except for UnionAll
+    // which has a special non-bits based egal
+    bool justbits1 = jl_is_concrete_immutable(rt1) && !jl_is_kind(rt1);
+    bool justbits2 = jl_is_concrete_immutable(rt2) && !jl_is_kind(rt2);
     if (justbits1 || justbits2) { // whether this type is unique'd by value
         return emit_nullcheck_guard2(ctx, nullcheck1, nullcheck2, [&] () -> Value* {
             jl_datatype_t *typ = (jl_datatype_t*)(justbits1 ? rt1 : rt2);

test/compiler/codegen.jl

@@ -999,3 +999,8 @@ for (T, StructName) in ((Int128, :Issue55558), (UInt128, :UIssue55558))
         @test sizeof($(StructName)) == 48 broken=broken_i128
     end
 end
+
+@noinline Base.@nospecializeinfer f55768(@nospecialize z::UnionAll) = z === Vector
+@test f55768(Vector)
+@test f55768(Vector{T} where T)
+@test !f55768(Vector{S} where S)