https://gcc.gnu.org/g:44402e206e07ebeb817ac8587a87fe8438cb0b0e
commit 44402e206e07ebeb817ac8587a87fe8438cb0b0e
Author: Ondřej Machota <ondrejmach...@gmail.com>
Date: Tue Mar 18 22:55:02 2025 +0100
rtl-ssa-dce: mark global regs as prelive with ssa
Diff:
---
gcc/dce.cc | 100 ++++++++++++++++++++++++++++---------------------------------
1 file changed, 45 insertions(+), 55 deletions(-)
diff --git a/gcc/dce.cc b/gcc/dce.cc
index 42b63cbcfb81..62ab115455c0 100644
--- a/gcc/dce.cc
+++ b/gcc/dce.cc
@@ -1306,15 +1306,6 @@ public:
} // namespace
-
-bool sets_global_register(const_rtx rtx) {
- auto code = GET_CODE(rtx);
- if (GET_RTX_CLASS(code) != RTX_INSN)
- return false;
-
- return sets_global_register(static_cast<const rtx_insn*>(rtx));
-}
-
// We should mark stack registers
// use HARD_FRAME_POINTER_REGNUM, REGNO_PTR_FRAME_P
// muzeme mit parallel, ktery ma napr. dva single sety, nebo asm statement
@@ -1327,12 +1318,12 @@ bool sets_global_register(rtx_insn* insn) {
rtx dest = SET_DEST(set);
// TODO : rewrite to simple return
- //std::cerr << "first pseudo: " << FIRST_PSEUDO_REGISTER << '\n';
+ std::cerr << "first pseudo: " << FIRST_PSEUDO_REGISTER << '\n';
//std::cerr << "register: " << REGNO(dest) << "\n";
//debug(insn);
// If I understand correctly, global_regs[i] is 1 iff reg i is used
if (REG_P(dest) && HARD_REGISTER_NUM_P(REGNO(dest))) { // &&
global_regs[REGNO(dest)]
- //std::cerr << "sets_global_register: true\n";
+ std::cerr << "sets_global_register: true\n";
return true;
}
@@ -1378,10 +1369,6 @@ bool side_effects_with_mem (const_rtx x)
case ASM_OPERANDS:
return true;
- // This should rather by RTX_BODY in is_rtx_insn_prelive - like global
clobber
- // case USE:
- // return true;
-
default:
break;
}
@@ -1451,8 +1438,8 @@ bool is_rtx_insn_prelive(rtx_insn *insn) {
return true;
// Mark set of a global register
- if (sets_global_register(insn)) // check rtx_class with GET_RTX_CLASS if
RTX_ISNS and convert if needed
- return true;
+ // if (sets_global_register(insn)) // check rtx_class with GET_RTX_CLASS if
RTX_ISNS and convert if needed
+ // return true;
rtx body = PATTERN(insn);
if (GET_CODE(body) == CLOBBER) //
gcc/gcc/testsuite/gcc.c-torture/compile/20000605-1.c
@@ -1472,7 +1459,7 @@ bool is_rtx_insn_prelive(rtx_insn *insn) {
// It seems that the issue was due to trap_if rtl insn and fixed with
may_trap_or_fault_p
// What about can_throw_internal?
// || can_throw_internal(body) - testy na ntb prochazi
- if (side_effects_with_mem(body)) // || may_trap_or_fault_p(body))
+ if (side_effects_with_mem(body)) // || may_trap_or_fault_p(body)) //
replaced by TRAP_IF
return true;
return false;
@@ -1506,39 +1493,28 @@ bool is_prelive(insn_info *insn)
gcc_assert (insn->is_real());
auto rtl = insn->rtl();
- if (!INSN_P(rtl)) // This might be useless
- return false;
+ for (auto&& __def : insn->defs()) {
+ def_info * def = __def;
+ if (!def->is_reg()) {
+ continue;
+ }
+
+ // this ignore clobbers, which is probably fine
+ if (def->kind() == access_kind::SET && HARD_REGISTER_NUM_P(def->regno())) {
+ // We might try to write something like def->regno() == REGNO
(pic_offset_table_rtx) ...
+ // TODO : else if (DF_REF_REG (def) == pic_offset_table_rtx && REGNO
(pic_offset_table_rtx) >= FIRST_PSEUDO_REGISTER)
+ // std::cerr << "hello, dear hard register! regno: " << def->regno() <<
"\n";
+ // debug(rtl);
+ return true;
+ }
+ }
- auto res = is_rtx_insn_prelive(rtl);
+ // auto res = is_rtx_insn_prelive(rtl);
//std::cerr << "Trying to mark insn: " << insn->uid() << " as prelive: " <<
res << '\n';
return is_rtx_insn_prelive(rtl);
}
-static void
-rtl_ssa_dce_init()
-{
- // internal compiler error: gcc.c-torture/execute/20040811-1.c -
rtl_ssa::function_info::add_phi_nodes
-
- calculate_dominance_info(CDI_DOMINATORS);
- // here we create ssa form for function
- crtl->ssa = new rtl_ssa::function_info(cfun);
-}
-
-static void
-rtl_ssa_dce_done()
-{
- free_dominance_info(CDI_DOMINATORS);
- if (crtl->ssa->perform_pending_updates())
- cleanup_cfg(0);
-
- delete crtl->ssa;
- crtl->ssa = nullptr;
-
- if (dump_file)
- fprintf(dump_file, "\nFinished running rtl_ssa_dce\n\n");
-}
-
static void
rtl_ssa_dce_mark_live(insn_info *info, vec<insn_info *> &worklist,
std::unordered_set<insn_info *> &marked)
{
@@ -1558,18 +1534,8 @@ rtl_ssa_dce_prelive(std::unordered_set<insn_info *>
&marked)
for (insn_info *insn = crtl->ssa->first_insn(); insn; insn = next)
{
next = insn->next_any_insn();
- /*
- I would like to mark visited instruction with something like plf (Pass
local flags) as in gimple
-
- This file contains some useful functions: e.g. marked_insn_p, mark_insn
- mark_insn does much more than I want now...
- It does quite a useful job. If rtl_insn is a call and it is obsolete, it
will find call arguments.
- */
-
if (is_prelive(insn))
- {
rtl_ssa_dce_mark_live(insn, worklist, marked);
- }
// if (insn->can_be_optimized () || insn->is_debug_insn ())
// if (fwprop_insn (insn, fwprop_addr_p))
@@ -1712,6 +1678,30 @@ rtl_ssa_dce_sweep(std::unordered_set<insn_info *> marked)
}
}
+static void
+rtl_ssa_dce_init()
+{
+ // internal compiler error: gcc.c-torture/execute/20040811-1.c -
rtl_ssa::function_info::add_phi_nodes
+
+ calculate_dominance_info(CDI_DOMINATORS);
+ // here we create ssa form for function
+ crtl->ssa = new rtl_ssa::function_info(cfun);
+}
+
+static void
+rtl_ssa_dce_done()
+{
+ free_dominance_info(CDI_DOMINATORS);
+ if (crtl->ssa->perform_pending_updates())
+ cleanup_cfg(0);
+
+ delete crtl->ssa;
+ crtl->ssa = nullptr;
+
+ if (dump_file)
+ fprintf(dump_file, "\nFinished running rtl_ssa_dce\n\n");
+}
+
static unsigned int
rtl_ssa_dce()
{
