Fix #41975 - Dropped typecheck in GotoIfNot

base/compiler/abstractinterpretation.jl

@@ -1780,6 +1780,10 @@ function typeinf_local(interp::AbstractInterpreter, frame::InferenceState)
                 end
                 condval = maybe_extract_const_bool(condt)
                 l = stmt.dest::Int
+                if l == 0
+                    # Bool typecheck only - not control flow effect
+                    break
+                end
                 if !isempty(frame.pclimitations)
                     # we can't model the possible effect of control
                     # dependencies on the return value, so we propagate it

base/compiler/optimize.jl

@@ -543,7 +543,7 @@ function statement_or_branch_cost(@nospecialize(stmt), line::Int, src::Union{Cod
         # summing the cost of the not-taken branch
         thiscost = dst(stmt.label) < line ? 40 : 0
     elseif stmt isa GotoIfNot
-        thiscost = dst(stmt.dest) < line ? 40 : 0
+        thiscost = (stmt.dest != 0 && dst(stmt.dest) < line) ? 40 : 0
     end
     return thiscost
 end
@@ -619,7 +619,7 @@ function renumber_ir_elements!(body::Vector{Any}, ssachangemap::Vector{Int}, lab
             if isa(cond, SSAValue)
                 cond = SSAValue(cond.id + ssachangemap[cond.id])
             end
-            body[i] = GotoIfNot(cond, el.dest + labelchangemap[el.dest])
+            body[i] = GotoIfNot(cond, el.dest == 0 ? 0 : el.dest + labelchangemap[el.dest])
         elseif isa(el, ReturnNode)
             if isdefined(el, :val)
                 val = el.val

base/compiler/ssair/inlining.jl

@@ -402,7 +402,7 @@ function ir_inline_item!(compact::IncrementalCompact, idx::Int, argexprs::Vector
             elseif isa(stmt′, Expr) && stmt′.head === :enter
                 stmt′ = Expr(:enter, stmt′.args[1]::Int + bb_offset)
             elseif isa(stmt′, GotoIfNot)
-                stmt′ = GotoIfNot(stmt′.cond, stmt′.dest + bb_offset)
+                stmt′ = GotoIfNot(stmt′.cond, stmt′.dest == 0 ? 0 : stmt′.dest + bb_offset)
             elseif isa(stmt′, PhiNode)
                 stmt′ = PhiNode(Int32[edge+bb_offset for edge in stmt′.edges], stmt′.values)
             end
@@ -588,7 +588,7 @@ function batch_inline!(todo::Vector{Pair{Int, Any}}, ir::IRCode, linetable::Vect
             elseif isa(stmt, Expr) && stmt.head === :enter
                 compact[idx] = Expr(:enter, state.bb_rename[stmt.args[1]::Int])
             elseif isa(stmt, GotoIfNot)
-                compact[idx] = GotoIfNot(stmt.cond, state.bb_rename[stmt.dest])
+                compact[idx] = GotoIfNot(stmt.cond, stmt.dest == 0 ? 0 : state.bb_rename[stmt.dest])
             elseif isa(stmt, PhiNode)
                 compact[idx] = PhiNode(Int32[edge == length(state.bb_rename) ? length(state.new_cfg_blocks) : state.bb_rename[edge+1]-1 for edge in stmt.edges], stmt.values)
             end

base/compiler/ssair/ir.jl

@@ -40,7 +40,7 @@ function basic_blocks_starts(stmts::Vector{Any})
     for idx in 1:length(stmts)
         stmt = stmts[idx]
         # Terminators
-        if isa(stmt, GotoIfNot)
+        if isa(stmt, GotoIfNot) && stmt.dest != 0
             push!(jump_dests, idx+1)
             push!(jump_dests, stmt.dest)
         elseif isa(stmt, ReturnNode)
@@ -106,7 +106,7 @@ function compute_basic_blocks(stmts::Vector{Any})
             continue
         end
         # Conditional Branch
-        if isa(terminator, GotoIfNot)
+        if isa(terminator, GotoIfNot) && terminator.dest != 0
             block′ = block_for_inst(basic_block_index, terminator.dest)
             if block′ == num + 1
                 # This GotoIfNot acts like a noop - treat it as such.
@@ -1012,17 +1012,19 @@ function process_node!(compact::IncrementalCompact, result_idx::Int, inst::Instr
         result[result_idx][:inst] = stmt
         cond = stmt.cond
         if isa(cond, Bool) && compact.fold_constant_branches
-            if cond
+            if cond || stmt.dest == 0
                 result[result_idx][:inst] = nothing
-                kill_edge!(compact, active_bb, active_bb, stmt.dest)
+                if stmt.dest != 0
+                    kill_edge!(compact, active_bb, active_bb, stmt.dest)
+                end
                 # Don't increment result_idx => Drop this statement
             else
                 result[result_idx][:inst] = GotoNode(compact.bb_rename_succ[stmt.dest])
                 kill_edge!(compact, active_bb, active_bb, active_bb+1)
                 result_idx += 1
             end
         else
-            result[result_idx][:inst] = GotoIfNot(cond, compact.bb_rename_succ[stmt.dest])
+            result[result_idx][:inst] = GotoIfNot(cond, stmt.dest == 0 ? 0 : compact.bb_rename_succ[stmt.dest])
             result_idx += 1
         end
     elseif isa(stmt, Expr)

base/compiler/ssair/legacy.jl

@@ -19,7 +19,7 @@ function inflate_ir(ci::CodeInfo, sptypes::Vector{Any}, argtypes::Vector{Any})
         if isa(stmt, GotoNode)
             code[i] = GotoNode(block_for_inst(cfg, stmt.label))
         elseif isa(stmt, GotoIfNot)
-            code[i] = GotoIfNot(stmt.cond, block_for_inst(cfg, stmt.dest))
+            code[i] = GotoIfNot(stmt.cond, stmt.dest == 0 ? 0 : block_for_inst(cfg, stmt.dest))
         elseif isa(stmt, PhiNode)
             code[i] = PhiNode(Int32[block_for_inst(cfg, Int(edge)) for edge in stmt.edges], stmt.values)
         elseif isa(stmt, Expr) && stmt.head === :enter
@@ -57,7 +57,7 @@ function replace_code_newstyle!(ci::CodeInfo, ir::IRCode, nargs::Int)
         if isa(stmt, GotoNode)
             stmt = GotoNode(first(ir.cfg.blocks[stmt.label].stmts))
         elseif isa(stmt, GotoIfNot)
-            stmt = GotoIfNot(stmt.cond, first(ir.cfg.blocks[stmt.dest].stmts))
+            stmt = GotoIfNot(stmt.cond, stmt.dest == 0 ? 0 : first(ir.cfg.blocks[stmt.dest].stmts))
         elseif isa(stmt, PhiNode)
             stmt = PhiNode(Int32[last(ir.cfg.blocks[edge].stmts) for edge in stmt.edges], stmt.values)
         elseif isa(stmt, Expr) && stmt.head === :enter

base/compiler/ssair/queries.jl

@@ -8,7 +8,9 @@ function stmt_effect_free(@nospecialize(stmt), @nospecialize(rt), src, sptypes::
     isa(stmt, PhiNode) && return true
     isa(stmt, ReturnNode) && return false
     isa(stmt, GotoNode) && return false
-    isa(stmt, GotoIfNot) && return false
+    if isa(stmt, GotoIfNot)
+        return stmt.dest == 0 && argextype(stmt.cond, src, sptypes) ⊑ Bool
+    end
     isa(stmt, Slot) && return false # Slots shouldn't occur in the IR at this point, but let's be defensive here
     isa(stmt, GlobalRef) && return isdefined(stmt.mod, stmt.name)
     if isa(stmt, Expr)

base/compiler/ssair/show.jl

@@ -129,7 +129,7 @@ end
 
 show_unquoted(io::IO, stmt::GotoIfNot, indent::Int, ::Int) = show_unquoted_gotoifnot(io, stmt, indent, "%")
 function show_unquoted_gotoifnot(io::IO, stmt::GotoIfNot, indent::Int, prefix::String)
-    print(io, "goto ", prefix, stmt.dest, " if not ")
+    print(io, "goto ", prefix, stmt.dest == 0 ? "fallthrough" : stmt.dest, " if not ")
     show_unquoted(io, stmt.cond, indent)
 end
 
@@ -536,7 +536,7 @@ function statement_indices_to_labels(stmt, cfg::CFG)
             stmt = Expr(:enter, block_for_inst(cfg, stmt.args[1]::Int))
         end
     elseif isa(stmt, GotoIfNot)
-        stmt = GotoIfNot(stmt.cond, block_for_inst(cfg, stmt.dest))
+        stmt = GotoIfNot(stmt.cond, stmt.dest == 0 ? 0 : block_for_inst(cfg, stmt.dest))
     elseif stmt isa GotoNode
         stmt = GotoNode(block_for_inst(cfg, stmt.label))
     elseif stmt isa PhiNode

base/compiler/ssair/slot2ssa.jl

@@ -480,7 +480,7 @@ function domsort_ssa!(ir::IRCode, domtree::DomTree)
                 node = result[nidx]
                 node[:inst], node[:type], node[:line] = GotoNode(bb_rename[bb + 1]), Any, 0
             end
-            result[inst_range[end]][:inst] = GotoIfNot(terminator.cond, bb_rename[terminator.dest])
+            result[inst_range[end]][:inst] = GotoIfNot(terminator.cond, terminator.dest == 0 ? 0 : bb_rename[terminator.dest])
         elseif !isa(terminator, ReturnNode)
             if isa(terminator, Expr)
                 if terminator.head == :enter
@@ -821,11 +821,14 @@ function construct_ssa!(ci::CodeInfo, ir::IRCode, domtree::DomTree, defuse,
         # Convert GotoNode/GotoIfNot/PhiNode to BB addressing
         if isa(stmt, GotoNode)
             new_code[idx] = GotoNode(block_for_inst(cfg, stmt.label))
-        elseif isa(stmt, GotoIfNot)
+        elseif isa(stmt, GotoIfNot) && stmt.dest != 0
             new_dest = block_for_inst(cfg, stmt.dest)
             if new_dest == bb+1
-                # Drop this node - it's a noop
-                new_code[idx] = stmt.cond
+                # We need to keep this node for the bool typecheck
+                # (until we can prove that it doesn't throw at least),
+                # but we null the destination and don't record a separate
+                # edge to keep the unique edge invariant.
+                new_code[idx] = GotoIfNot(stmt.cond, 0)
             else
                 new_code[idx] = GotoIfNot(stmt.cond, new_dest)
             end

base/compiler/ssair/verify.jl

@@ -105,7 +105,16 @@ function verify_ir(ir::IRCode, print::Bool=true)
                 @verify_error "Block $idx terminator forms a double edge to block $(idx+1)"
                 error("")
             end
-            if length(block.succs) != 2 || (block.succs != [terminator.dest, idx+1] && block.succs != [idx+1, terminator.dest])
+            if length(block.succs) == 1
+                if block.dest != 0
+                    @verify_error "Block $idx terminator has non-zero dest but only one successor"
+                    error("")
+                end
+                if block.succs[1] != idx + 1
+                    @verify_error "Block $idx successors ($(block.succs)), does not match GotoIfNot fallthrough"
+                    error("")
+                end
+            elseif length(block.succs) != 2 || (block.succs != [terminator.dest, idx+1] && block.succs != [idx+1, terminator.dest])
                 @verify_error "Block $idx successors ($(block.succs)), does not match GotoIfNot terminator"
                 error("")
             end

base/compiler/typeinfer.jl

@@ -637,9 +637,9 @@ function type_annotate!(sv::InferenceState, run_optimizer::Bool)
     # replace GotoIfNot with its condition if the branch target is unreachable
     for i = 1:nexpr
         expr = body[i]
-        if isa(expr, GotoIfNot)
+        if isa(expr, GotoIfNot) && expr.dest != 0
             if !isa(states[expr.dest], VarTable)
-                body[i] = expr.cond
+                body[i] = GotoIfNot(expr.cond, 0)
             end
         end
     end

base/compiler/utilities.jl

@@ -350,10 +350,10 @@ function find_throw_blocks(code::Vector{Any}, ir = RefValue{IRCode}())
         elseif isa(s, GotoIfNot)
             if i+1 in stmts
                 tgt = s.dest::Int
-                if isassigned(ir)
+                if isassigned(ir) && tgt != 0
                     tgt = first(ir[].cfg.blocks[tgt].stmts)
                 end
-                if tgt in stmts
+                if tgt == 0 || tgt in stmts
                     push!(stmts, i)
                 end
             end

base/meta.jl

@@ -364,7 +364,7 @@ function _partially_inline!(@nospecialize(x), slot_replacements::Vector{Any},
         return Core.GotoIfNot(
             _partially_inline!(x.cond, slot_replacements, type_signature, static_param_values,
                                slot_offset, statement_offset, boundscheck),
-            x.dest + statement_offset,
+            x.dest == 0 ? 0 : x.dest + statement_offset,
         )
     end
     if isa(x, Expr)

src/codegen.cpp

@@ -7002,7 +7002,8 @@ static std::pair<std::unique_ptr<Module>, jl_llvm_functions_t>
             jl_value_t *stmt = jl_array_ptr_ref(stmts, i);
             if (jl_is_gotoifnot(stmt)) {
                 int dest = jl_gotoifnot_label(stmt);
-                branch_targets.insert(dest);
+                if (dest != 0)
+                    branch_targets.insert(dest);
                 // The next 1-indexed statement
                 branch_targets.insert(i + 2);
             } else if (jl_is_returnnode(stmt)) {
@@ -7190,13 +7191,17 @@ static std::pair<std::unique_ptr<Module>, jl_llvm_functions_t>
             Value *isfalse = emit_condition(ctx, cond, "if");
             mallocVisitStmt(debuginfoloc, nullptr);
             come_from_bb[cursor+1] = ctx.builder.GetInsertBlock();
-            workstack.push_back(lname - 1);
-            BasicBlock *ifnot = BB[lname];
             BasicBlock *ifso = BB[cursor+2];
-            if (ifnot == ifso)
-                ctx.builder.CreateBr(ifnot);
-            else
-                ctx.builder.CreateCondBr(isfalse, ifnot, ifso);
+            if (lname == 0) {
+                ctx.builder.CreateBr(ifso);
+            } else {
+                workstack.push_back(lname - 1);
+                BasicBlock *ifnot = BB[lname];
+                if (ifnot == ifso)
+                    ctx.builder.CreateBr(ifnot);
+                else
+                    ctx.builder.CreateCondBr(isfalse, ifnot, ifso);
+            }
             find_next_stmt(cursor + 1);
             continue;
         }

src/interpreter.c

@@ -430,7 +430,7 @@ static jl_value_t *eval_body(jl_array_t *stmts, interpreter_state *s, size_t ip,
         }
         else if (jl_is_gotoifnot(stmt)) {
             jl_value_t *cond = eval_value(jl_gotoifnot_cond(stmt), s);
-            if (cond == jl_false) {
+            if (cond == jl_false && jl_gotoifnot_label(stmt) != 0) {
                 next_ip = jl_gotoifnot_label(stmt) - 1;
             }
             else if (cond != jl_true) {

src/toplevel.c

@@ -399,7 +399,7 @@ static void body_attributes(jl_array_t *body, int *has_intrinsics, int *has_defs
                     *has_loops = 1;
             }
             else if (jl_is_gotoifnot(stmt)) {
-                if (jl_gotoifnot_label(stmt) <= i)
+                if (jl_gotoifnot_label(stmt) != 0 && jl_gotoifnot_label(stmt) <= i)
                     *has_loops = 1;
             }
         }

test/compiler/ssair.jl

@@ -310,3 +310,7 @@ let cfg = CFG(BasicBlock[
     Compiler.domtree_insert_edge!(domtree, cfg.blocks, 1, 3)
     @test domtree.idoms_bb == Compiler.naive_idoms(cfg.blocks) == [0, 1, 1, 3, 1, 4]
 end
+
+# Issue #41975 - SSA conversion drops type check
+f_if_typecheck() = (if nothing; end; unsafe_load(Ptr{Int}(0)))
+@test_throws TypeError f_if_typecheck()