Merge branch 'master' into fix/palloca

vyper/venom/venom_to_assembly.py

@@ -295,7 +295,8 @@ def _generate_evm_for_basicblock_r(
  asm.append(f"_sym_{basicblock.label}")
  asm.append("JUMPDEST")
 
- self.clean_stack_from_cfg_in(asm, basicblock, stack)
+ if len(basicblock.cfg_in) == 1:
+ self.clean_stack_from_cfg_in(asm, basicblock, stack)
 
  all_insts = sorted(basicblock.instructions, key=lambda x: x.opcode != "param")
 
@@ -321,26 +322,28 @@ def _generate_evm_for_basicblock_r(
  def clean_stack_from_cfg_in(
  self, asm: list, basicblock: IRBasicBlock, stack: StackModel
  ) -> None:
- if len(basicblock.cfg_in) == 0:
- return
-
- to_pop = OrderedSet[IRVariable]()
- for in_bb in basicblock.cfg_in:
- # inputs is the input variables we need from in_bb
- inputs = self.liveness_analysis.input_vars_from(in_bb, basicblock)
-
- # layout is the output stack layout for in_bb (which works
- # for all possible cfg_outs from the in_bb).
- layout = in_bb.out_vars
-
- # pop all the stack items which in_bb produced which we don't need.
- to_pop |= layout.difference(inputs)
-
+ # the input block is a splitter block, like jnz or djmp
+ assert len(basicblock.cfg_in) == 1
+ in_bb = basicblock.cfg_in.first()
+ assert len(in_bb.cfg_out) > 1
+
+ # inputs is the input variables we need from in_bb
+ inputs = self.liveness_analysis.input_vars_from(in_bb, basicblock)
+
+ # layout is the output stack layout for in_bb (which works
+ # for all possible cfg_outs from the in_bb, in_bb is responsible
+ # for making sure its output stack layout works no matter which
+ # bb it jumps into).
+ layout = in_bb.out_vars
+ to_pop = list(layout.difference(inputs))
+
+ # small heuristic: pop from shallowest first.
+ to_pop.sort(key=lambda var: -stack.get_depth(var))
+
+ # NOTE: we could get more fancy and try to optimize the swap
+ # operations here, there is probably some more room for optimization.
  for var in to_pop:
  depth = stack.get_depth(var)
- # don't pop phantom phi inputs
- if depth is StackModel.NOT_IN_STACK:
- continue
 
  if depth != 0:
  self.swap(asm, stack, depth)