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stage1: Make x and false/x or true comptime-known

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We need to be careful to respect side-effects/branching in these
cases, but otherwise this behaves very similarly to multiplication.
`lhs and rhs == false` if either lhs or rhs is comptime-known `false`,
just like `lhs * rhs == 0` if either lhs or rhs is comptime-known to
be zero.

Similar reasoning applies to `lhs or rhs`.
This commit is contained in:
Cody Tapscott 2022-10-30 12:21:37 -07:00
parent 1696434063
commit 2f732deb3d
3 changed files with 54 additions and 22 deletions
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1
src/stage1/all_types.hpp
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@ -2922,6 +2922,7 @@ struct Stage1ZirInstPhi {
Stage1ZirInst base;
size_t incoming_count;
bool merge_comptime;
Stage1ZirBasicBlock **incoming_blocks;
Stage1ZirInst **incoming_values;
ResultLocPeerParent *peer_parent;

39
src/stage1/astgen.cpp
View File

@ -1304,7 +1304,7 @@ static Stage1ZirInst *ir_build_call_src(Stage1AstGen *ag, Scope *scope, AstNode
return &call_instruction->base;
}
static Stage1ZirInst *ir_build_phi(Stage1AstGen *ag, Scope *scope, AstNode *source_node,
static Stage1ZirInst *ir_build_phi(Stage1AstGen *ag, Scope *scope, AstNode *source_node, bool merge_comptime,
size_t incoming_count, Stage1ZirBasicBlock **incoming_blocks, Stage1ZirInst **incoming_values,
ResultLocPeerParent *peer_parent)
{
@ -1316,6 +1316,7 @@ static Stage1ZirInst *ir_build_phi(Stage1AstGen *ag, Scope *scope, AstNode *sour
phi_instruction->incoming_blocks = incoming_blocks;
phi_instruction->incoming_values = incoming_values;
phi_instruction->peer_parent = peer_parent;
phi_instruction->merge_comptime = merge_comptime;
for (size_t i = 0; i < incoming_count; i += 1) {
ir_ref_bb(incoming_blocks[i]);
@ -3393,7 +3394,7 @@ static Stage1ZirInst *astgen_block(Stage1AstGen *ag, Scope *parent_scope, AstNod
scope_block->peer_parent->peers.last()->next_bb = scope_block->end_block;
}
ir_set_cursor_at_end_and_append_block(ag, scope_block->end_block);
Stage1ZirInst *phi = ir_build_phi(ag, parent_scope, block_node, incoming_blocks.length,
Stage1ZirInst *phi = ir_build_phi(ag, parent_scope, block_node, false, incoming_blocks.length,
incoming_blocks.items, incoming_values.items, scope_block->peer_parent);
return ir_expr_wrap(ag, parent_scope, phi, result_loc);
} else {
@ -3423,7 +3424,7 @@ static Stage1ZirInst *astgen_block(Stage1AstGen *ag, Scope *parent_scope, AstNod
if (block_node->data.block.name != nullptr) {
ir_build_br(ag, parent_scope, block_node, scope_block->end_block, scope_block->is_comptime);
ir_set_cursor_at_end_and_append_block(ag, scope_block->end_block);
Stage1ZirInst *phi = ir_build_phi(ag, parent_scope, block_node, incoming_blocks.length,
Stage1ZirInst *phi = ir_build_phi(ag, parent_scope, block_node, false, incoming_blocks.length,
incoming_blocks.items, incoming_values.items, scope_block->peer_parent);
result = ir_expr_wrap(ag, parent_scope, phi, result_loc);
} else {
@ -3527,6 +3528,7 @@ static Stage1ZirInst *astgen_bool_or(Stage1AstGen *ag, Scope *scope, AstNode *no
// block for when val1 == true (don't even evaluate the second part)
Stage1ZirBasicBlock *true_block = ir_create_basic_block(ag, scope, "BoolOrTrue");
Stage1ZirInst *val1_true = ir_build_const_bool(ag, scope, node, true);
ir_build_cond_br(ag, scope, node, val1, true_block, false_block, is_comptime);
ir_set_cursor_at_end_and_append_block(ag, false_block);
@ -3540,13 +3542,14 @@ static Stage1ZirInst *astgen_bool_or(Stage1AstGen *ag, Scope *scope, AstNode *no
ir_set_cursor_at_end_and_append_block(ag, true_block);
Stage1ZirInst **incoming_values = heap::c_allocator.allocate<Stage1ZirInst *>(2);
incoming_values[0] = val1;
incoming_values[0] = val1_true;
incoming_values[1] = val2;
Stage1ZirBasicBlock **incoming_blocks = heap::c_allocator.allocate<Stage1ZirBasicBlock *>(2);
incoming_blocks[0] = post_val1_block;
incoming_blocks[1] = post_val2_block;
return ir_build_phi(ag, scope, node, 2, incoming_blocks, incoming_values, nullptr);
const bool merge_comptime = true;
return ir_build_phi(ag, scope, node, merge_comptime, 2, incoming_blocks, incoming_values, nullptr);
}
static Stage1ZirInst *astgen_bool_and(Stage1AstGen *ag, Scope *scope, AstNode *node) {
@ -3569,6 +3572,7 @@ static Stage1ZirInst *astgen_bool_and(Stage1AstGen *ag, Scope *scope, AstNode *n
// block for when val1 == false (don't even evaluate the second part)
Stage1ZirBasicBlock *false_block = ir_create_basic_block(ag, scope, "BoolAndFalse");
Stage1ZirInst *val1_false = ir_build_const_bool(ag, scope, node, false);
ir_build_cond_br(ag, scope, node, val1, true_block, false_block, is_comptime);
ir_set_cursor_at_end_and_append_block(ag, true_block);
@ -3582,13 +3586,14 @@ static Stage1ZirInst *astgen_bool_and(Stage1AstGen *ag, Scope *scope, AstNode *n
ir_set_cursor_at_end_and_append_block(ag, false_block);
Stage1ZirInst **incoming_values = heap::c_allocator.allocate<Stage1ZirInst *>(2);
incoming_values[0] = val1;
incoming_values[0] = val1_false;
incoming_values[1] = val2;
Stage1ZirBasicBlock **incoming_blocks = heap::c_allocator.allocate<Stage1ZirBasicBlock *>(2);
incoming_blocks[0] = post_val1_block;
incoming_blocks[1] = post_val2_block;
return ir_build_phi(ag, scope, node, 2, incoming_blocks, incoming_values, nullptr);
const bool merge_comptime = true;
return ir_build_phi(ag, scope, node, merge_comptime, 2, incoming_blocks, incoming_values, nullptr);
}
static ResultLocPeerParent *ir_build_result_peers(Stage1AstGen *ag, Stage1ZirInst *cond_br_inst,
@ -3678,7 +3683,7 @@ static Stage1ZirInst *astgen_orelse(Stage1AstGen *ag, Scope *parent_scope, AstNo
Stage1ZirBasicBlock **incoming_blocks = heap::c_allocator.allocate<Stage1ZirBasicBlock *>(2);
incoming_blocks[0] = after_null_block;
incoming_blocks[1] = after_ok_block;
Stage1ZirInst *phi = ir_build_phi(ag, parent_scope, node, 2, incoming_blocks, incoming_values, peer_parent);
Stage1ZirInst *phi = ir_build_phi(ag, parent_scope, node, false, 2, incoming_blocks, incoming_values, peer_parent);
return ir_lval_wrap(ag, parent_scope, phi, lval, result_loc);
}
@ -5589,7 +5594,7 @@ static Stage1ZirInst *astgen_if_bool_expr(Stage1AstGen *ag, Scope *scope, AstNod
incoming_blocks[0] = after_then_block;
incoming_blocks[1] = after_else_block;
Stage1ZirInst *phi = ir_build_phi(ag, scope, node, 2, incoming_blocks, incoming_values, peer_parent);
Stage1ZirInst *phi = ir_build_phi(ag, scope, node, false, 2, incoming_blocks, incoming_values, peer_parent);
return ir_expr_wrap(ag, scope, phi, result_loc);
}
@ -6224,7 +6229,7 @@ static Stage1ZirInst *astgen_while_expr(Stage1AstGen *ag, Scope *scope, AstNode
peer_parent->peers.last()->next_bb = end_block;
}
Stage1ZirInst *phi = ir_build_phi(ag, scope, node, incoming_blocks.length,
Stage1ZirInst *phi = ir_build_phi(ag, scope, node, false, incoming_blocks.length,
incoming_blocks.items, incoming_values.items, peer_parent);
return ir_expr_wrap(ag, scope, phi, result_loc);
} else if (var_symbol != nullptr) {
@ -6334,7 +6339,7 @@ static Stage1ZirInst *astgen_while_expr(Stage1AstGen *ag, Scope *scope, AstNode
peer_parent->peers.last()->next_bb = end_block;
}
Stage1ZirInst *phi = ir_build_phi(ag, scope, node, incoming_blocks.length,
Stage1ZirInst *phi = ir_build_phi(ag, scope, node, false, incoming_blocks.length,
incoming_blocks.items, incoming_values.items, peer_parent);
return ir_expr_wrap(ag, scope, phi, result_loc);
} else {
@ -6430,7 +6435,7 @@ static Stage1ZirInst *astgen_while_expr(Stage1AstGen *ag, Scope *scope, AstNode
peer_parent->peers.last()->next_bb = end_block;
}
Stage1ZirInst *phi = ir_build_phi(ag, scope, node, incoming_blocks.length,
Stage1ZirInst *phi = ir_build_phi(ag, scope, node, false, incoming_blocks.length,
incoming_blocks.items, incoming_values.items, peer_parent);
return ir_expr_wrap(ag, scope, phi, result_loc);
}
@ -6582,7 +6587,7 @@ static Stage1ZirInst *astgen_for_expr(Stage1AstGen *ag, Scope *parent_scope, Ast
peer_parent->peers.last()->next_bb = end_block;
}
Stage1ZirInst *phi = ir_build_phi(ag, parent_scope, node, incoming_blocks.length,
Stage1ZirInst *phi = ir_build_phi(ag, parent_scope, node, false, incoming_blocks.length,
incoming_blocks.items, incoming_values.items, peer_parent);
return ir_lval_wrap(ag, parent_scope, phi, lval, result_loc);
}
@ -6910,7 +6915,7 @@ static Stage1ZirInst *astgen_if_optional_expr(Stage1AstGen *ag, Scope *scope, As
incoming_blocks[0] = after_then_block;
incoming_blocks[1] = after_else_block;
Stage1ZirInst *phi = ir_build_phi(ag, scope, node, 2, incoming_blocks, incoming_values, peer_parent);
Stage1ZirInst *phi = ir_build_phi(ag, scope, node, false, 2, incoming_blocks, incoming_values, peer_parent);
return ir_expr_wrap(ag, scope, phi, result_loc);
}
@ -7008,7 +7013,7 @@ static Stage1ZirInst *astgen_if_err_expr(Stage1AstGen *ag, Scope *scope, AstNode
incoming_blocks[0] = after_then_block;
incoming_blocks[1] = after_else_block;
Stage1ZirInst *phi = ir_build_phi(ag, scope, node, 2, incoming_blocks, incoming_values, peer_parent);
Stage1ZirInst *phi = ir_build_phi(ag, scope, node, false, 2, incoming_blocks, incoming_values, peer_parent);
return ir_expr_wrap(ag, scope, phi, result_loc);
}
@ -7344,7 +7349,7 @@ static Stage1ZirInst *astgen_switch_expr(Stage1AstGen *ag, Scope *scope, AstNode
if (incoming_blocks.length == 0) {
result_instruction = ir_build_const_void(ag, scope, node);
} else {
result_instruction = ir_build_phi(ag, scope, node, incoming_blocks.length,
result_instruction = ir_build_phi(ag, scope, node, false, incoming_blocks.length,
incoming_blocks.items, incoming_values.items, peer_parent);
}
return ir_lval_wrap(ag, scope, result_instruction, lval, result_loc);
@ -7671,7 +7676,7 @@ static Stage1ZirInst *astgen_catch(Stage1AstGen *ag, Scope *parent_scope, AstNod
Stage1ZirBasicBlock **incoming_blocks = heap::c_allocator.allocate<Stage1ZirBasicBlock *>(2);
incoming_blocks[0] = after_err_block;
incoming_blocks[1] = after_ok_block;
Stage1ZirInst *phi = ir_build_phi(ag, parent_scope, node, 2, incoming_blocks, incoming_values, peer_parent);
Stage1ZirInst *phi = ir_build_phi(ag, parent_scope, node, false, 2, incoming_blocks, incoming_values, peer_parent);
return ir_lval_wrap(ag, parent_scope, phi, lval, result_loc);
}

36
src/stage1/ir.cpp
View File

@ -1318,12 +1318,37 @@ static Stage1AirInstCall *ir_build_call_gen(IrAnalyze *ira, Scope *scope, AstNod
return call_instruction;
}
static Stage1AirInst *ir_build_phi_gen(IrAnalyze *ira, Scope *scope, AstNode *source_node, size_t incoming_count,
Stage1AirBasicBlock **incoming_blocks, Stage1AirInst **incoming_values, ZigType *result_type)
static Stage1AirInst *ir_build_phi_gen(IrAnalyze *ira, Scope *scope, AstNode *source_node, bool merge_comptime,
size_t incoming_count, Stage1AirBasicBlock **incoming_blocks, Stage1AirInst **incoming_values, ZigType *result_type)
{
assert(incoming_count != 0);
assert(incoming_count != SIZE_MAX);
if (merge_comptime && instr_is_comptime(incoming_values[incoming_count - 1])) {
// We need to check whether all the merged values are comptime-known and equal.
// If so, we elide the runtime phi and replace it with any of the identical comptime-known values.
ZigValue *comptime_value = ir_resolve_const(ira, incoming_values[incoming_count - 1], UndefOk);
if (comptime_value == nullptr)
return ira->codegen->invalid_inst_gen;
for (size_t i = incoming_count - 1; i > 0;) {
i -= 1;
if (!instr_is_comptime(incoming_values[i])) {
comptime_value = nullptr;
break;
}
ZigValue *value = ir_resolve_const(ira, incoming_values[i], UndefOk);
if (value == nullptr)
return ira->codegen->invalid_inst_gen;
if (!const_values_equal(ira->codegen, comptime_value, value)) {
comptime_value = nullptr;
break;
}
}
if (comptime_value != nullptr)
return incoming_values[0];
}
Stage1AirInstPhi *phi_instruction = ir_build_inst_gen<Stage1AirInstPhi>(&ira->new_irb,
scope, source_node);
phi_instruction->base.value->type = result_type;
@ -9592,7 +9617,8 @@ static Stage1AirInst *ir_evaluate_cmp_optional_non_optional(IrAnalyze *ira, Scop
incoming_values[0] = null_result;
incoming_values[1] = non_null_cmp_result;
return ir_build_phi_gen(ira, scope, source_node, incoming_count, incoming_blocks, incoming_values, result_type);
const bool merge_comptime = false;
return ir_build_phi_gen(ira, scope, source_node, merge_comptime, incoming_count, incoming_blocks, incoming_values, result_type);
}
static Stage1AirInst *ir_analyze_cmp_optional_non_optional(IrAnalyze *ira, Scope *scope, AstNode *source_node,
@ -14757,8 +14783,8 @@ static Stage1AirInst *ir_analyze_instruction_phi(IrAnalyze *ira, Stage1ZirInstPh
ir_set_cursor_at_end_gen(&ira->new_irb, cur_bb);
Stage1AirInst *result = ir_build_phi_gen(ira, phi_instruction->base.scope,
phi_instruction->base.source_node, new_incoming_blocks.length,
new_incoming_blocks.items, new_incoming_values.items, resolved_type);
phi_instruction->base.source_node, phi_instruction->merge_comptime,
new_incoming_blocks.length, new_incoming_blocks.items, new_incoming_values.items, resolved_type);
if (all_stack_ptrs) {
assert(result->value->special == ConstValSpecialRuntime);