https://gcc.gnu.org/g:a8b182971c47e3793df08c7fbab6cde116bfcc4b
commit a8b182971c47e3793df08c7fbab6cde116bfcc4b
Author: Ondřej Machota <ondrejmach...@gmail.com>
Date: Tue Apr 8 18:00:34 2025 +0200
rtl-ssa-dce: fix eh
Diff:
---
gcc/dce.cc | 67 +++++++++++++++++++++++++-------------------------------------
1 file changed, 27 insertions(+), 40 deletions(-)
diff --git a/gcc/dce.cc b/gcc/dce.cc
index 6221e3b39910..c0ca89980254 100644
--- a/gcc/dce.cc
+++ b/gcc/dce.cc
@@ -1351,7 +1351,7 @@ bool is_rtx_prelive(const_rtx insn) {
switch (GET_CODE(insn)) {
case PREFETCH:
case UNSPEC:
- case TRAP_IF:
+ case TRAP_IF: /* testsuite/gcc.c-torture/execute/20020418-1.c */
return true;
default:
@@ -1372,7 +1372,6 @@ bool is_rtx_insn_prelive(rtx_insn *insn) {
/* Don't delete calls that may throw if we cannot do so. */
&& can_delete_call (insn))
return false;
- // return !find_call_stack_args (as_a <rtx_call_insn *> (insn), false, fast,
arg_stores);
if (!NONJUMP_INSN_P (insn))
/* This handles jumps, notes, call_insns, debug_insns, ... */
@@ -1396,10 +1395,6 @@ bool is_rtx_insn_prelive(rtx_insn *insn) {
case CLOBBER: // gcc/gcc/testsuite/gcc.c-torture/compile/20000605-1.c
case USE:
case VAR_LOCATION:
- /* Following cases might be removed since they are part of is_rtx_prelive
*/
- case PREFETCH:
- case TRAP_IF: /* testsuite/gcc.c-torture/execute/20020418-1.c */
- case UNSPEC:
return true;
case PARALLEL:
@@ -1415,13 +1410,19 @@ bool is_rtx_insn_prelive(rtx_insn *insn) {
bool is_prelive(insn_info *insn)
{
- /* Phi insns are never prelive, bb head + end also are artificial */
+ /* Phi insns are never prelive, bb head and end contain artificial uses that
+ we need to mark as prelive */
+ if (insn->is_bb_head() || insn->is_bb_end())
+ return true;
+
if (insn->is_artificial() || insn->is_debug_insn())
return false;
gcc_assert (insn->is_real());
auto rtl = insn->rtl();
+ /* I guess that a lot of conditions bellow are captured by artificial uses
+ of bb head and end insns. */
for (def_info * def : insn->defs()) {
/* The purpose of this pass is not to eliminate stores to memory... */
if (def->is_mem())
@@ -1431,59 +1432,44 @@ bool is_prelive(insn_info *insn)
gcc_assert(def->is_reg());
/* this ignores clobbers, which is probably fine */
- /* TODO : find something similar to mark_artificial_uses to mark only
- artificially-used registers.
- - df_get_regular_block_artificial_uses
- That should fix following test as assume
- gcc.c-torture/execute/20000503-1.c - flags register is unused. Not all
+ /* gcc.c-torture/execute/20000503-1.c - flags register is unused. Not all
hard registers should be marked... */
if (def->kind() != access_kind::SET)
continue;
/* This might be messed up a bit */
- if (def->regno() == FRAME_POINTER_REGNUM
- || def->regno() == STACK_POINTER_REGNUM)
- return true;
+ // if (def->regno() == FRAME_POINTER_REGNUM
+ // || def->regno() == STACK_POINTER_REGNUM)
+ // return true;
/* needed by gcc.c-torture/execute/pr51447.c */
if (HARD_REGISTER_NUM_P (def->regno())
&& global_regs[def->regno()])
- return true;
+ // { std::cout << "marked global reg: " << def->regno() << " in " <<
insn->uid() << '\n';
+ return true;
+ // }
- if (!HARD_FRAME_POINTER_IS_FRAME_POINTER
- && def->regno() == HARD_FRAME_POINTER_REGNUM)
- return true;
+ // if (!HARD_FRAME_POINTER_IS_FRAME_POINTER
+ // && def->regno() == HARD_FRAME_POINTER_REGNUM)
+ // return true;
- if (FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
- && fixed_regs[ARG_POINTER_REGNUM]
- && def->regno() == ARG_POINTER_REGNUM)
- return true;
+ // if (FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
+ // && fixed_regs[ARG_POINTER_REGNUM]
+ // && def->regno() == ARG_POINTER_REGNUM)
+ // return true;
unsigned int picreg = PIC_OFFSET_TABLE_REGNUM;
if (picreg != INVALID_REGNUM
&& fixed_regs[picreg]
&& def->regno() == picreg)
return true;
-
- // TODO : eh?
-
- /*
- if (def->kind() == access_kind::SET
- && (HARD_REGISTER_NUM_P(def->regno())
- || (pic_offset_table_rtx != nullptr
- && def->regno() == REGNO (pic_offset_table_rtx)
- && REGNO (pic_offset_table_rtx) >= FIRST_PSEUDO_REGISTER))
- ) {
- // find_reg_note(insn->rtl(), REG_UNUSED, def->regno())
- return true;
- } */
}
return is_rtx_insn_prelive(rtl);
}
static void
-rtl_ssa_dce_mark_prelive(insn_info *info, vec<insn_info *> &worklist,
+rtl_ssa_dce_mark_prelive_insn(insn_info *info, vec<insn_info *> &worklist,
std::unordered_set<insn_info *> &marked)
{
if (dump_file)
@@ -1494,12 +1480,12 @@ rtl_ssa_dce_mark_prelive(insn_info *info, vec<insn_info
*> &worklist,
}
static auto_vec<insn_info *>
-rtl_ssa_dce_prelive(std::unordered_set<insn_info *> &marked)
+rtl_ssa_dce_mark_prelive(std::unordered_set<insn_info *> &marked)
{
auto_vec<insn_info *> worklist;
for (insn_info * insn : crtl->ssa->all_insns()) {
if (is_prelive(insn))
- rtl_ssa_dce_mark_prelive(insn, worklist, marked);
+ rtl_ssa_dce_mark_prelive_insn(insn, worklist, marked);
}
return worklist;
@@ -1511,7 +1497,7 @@ rtl_ssa_dce_mark()
std::unordered_set<insn_info *> marked{};
/* Phi insn might have more that one phi node:
gcc/gcc/testsuite/gcc.c-torture/execute/20000224-1.c */
std::unordered_set<phi_info *> marked_phi_nodes{};
- auto prelive_insns = rtl_ssa_dce_prelive(marked);
+ auto prelive_insns = rtl_ssa_dce_mark_prelive(marked);
/* Extract uses from prelive insns to worklist */
auto_vec<set_info *> worklist{};
for (insn_info * insn : prelive_insns) {
@@ -1693,6 +1679,7 @@ static unsigned int
rtl_ssa_dce()
{
rtl_ssa_dce_init();
+ // debug(crtl->ssa);
std::unordered_set<insn_info *> marked = rtl_ssa_dce_mark();
rtl_ssa_dce_sweep(marked);
// std::cerr << "\033[31m" << "SSA debug start" << "\033[0m" << "\n";
