ZJIT: Just make a new block (ruby#17307)

I don't know what the original code was intending to do but we should always be making a new block.

Author: tekknolagi

zjit/src/hir.rs

@@ -7175,7 +7175,7 @@ pub fn iseq_to_hir(iseq: *const rb_iseq_t) -> Result<Function, ParseError> {
                     let pushval = get_arg(pc, 2);
                     if let Some(summary) = fun.polymorphic_summary(&profiles, self_param, exit_state.insn_idx) {
                         self_param = fun.push_insn(block, Insn::GuardType { val: self_param, guard_type: types::HeapBasicObject, state: exit_id, recompile: None });
-                        let join_block = insn_idx_to_block.get(&insn_idx).copied().unwrap_or_else(|| fun.new_block(insn_idx));
+                        let join_block = fun.new_block(insn_idx);
                         let join_param = fun.push_insn(join_block, Insn::Param);
                         // Dedup by expected shape so objects with different classes but the
                         // same shape can share code.
@@ -7566,7 +7566,7 @@ pub fn iseq_to_hir(iseq: *const rb_iseq_t) -> Result<Function, ParseError> {
                     // - unmodified: inspect the block handler and produce proxy/nil
                     let modified_block = fun.new_block(branch_insn_idx);
                     let unmodified_block = fun.new_block(branch_insn_idx);
-                    let join_block = insn_idx_to_block.get(&insn_idx).copied().unwrap_or_else(|| fun.new_block(insn_idx));
+                    let join_block = fun.new_block(insn_idx);
                     let join_result = fun.push_insn(join_block, Insn::Param);
                     let join_local = if level == 0 { Some(fun.push_insn(join_block, Insn::Param)) } else { None };
 
@@ -7800,7 +7800,7 @@ pub fn iseq_to_hir(iseq: *const rb_iseq_t) -> Result<Function, ParseError> {
                     // Otherwise, convert it to a Proc and store it to EP.
                     let modified_block = fun.new_block(branch_insn_idx);
                     let unmodified_block = fun.new_block(branch_insn_idx);
-                    let join_block = insn_idx_to_block.get(&insn_idx).copied().unwrap_or_else(|| fun.new_block(insn_idx));
+                    let join_block = fun.new_block(insn_idx);
                     let join_param = fun.push_insn(join_block, Insn::Param);
 
                     let ep = fun.push_insn(block, Insn::GetEP { level });
@@ -8042,7 +8042,7 @@ pub fn iseq_to_hir(iseq: *const rb_iseq_t) -> Result<Function, ParseError> {
                         let recv = state.stack_topn(argc as usize)?;  // args are on top
                         let entry_args = state.as_args(self_param);
                         if let Some(summary) = fun.polymorphic_summary(&profiles, recv, exit_state.insn_idx) {
-                            let join_block = insn_idx_to_block.get(&insn_idx).copied().unwrap_or_else(|| fun.new_block(insn_idx));
+                            let join_block = fun.new_block(insn_idx);
                             // Dedup by expected type so immediate/heap variants
                             // under the same Ruby class can still get separate branches.
                             let mut seen_types = Vec::with_capacity(summary.buckets().len());
@@ -8380,7 +8380,7 @@ pub fn iseq_to_hir(iseq: *const rb_iseq_t) -> Result<Function, ParseError> {
                     }
                     if let Some(summary) = fun.polymorphic_summary(&profiles, self_param, exit_state.insn_idx) {
                         self_param = fun.push_insn(block, Insn::GuardType { val: self_param, guard_type: types::HeapBasicObject, state: exit_id, recompile: None });
-                        let join_block = insn_idx_to_block.get(&insn_idx).copied().unwrap_or_else(|| fun.new_block(insn_idx));
+                        let join_block = fun.new_block(insn_idx);
                         let join_param = fun.push_insn(join_block, Insn::Param);
                         // Dedup by expected shape so objects with different classes but the same shape can share code
                         // TODO(max): De-duplicate further by checking ivar offsets to allow