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[patch RFA] Backport "dbr_schedule vs uninitialized registers" patch
- From: Kaz Kojima <kkojima at rr dot iij4u dot or dot jp>
- To: gcc-patches at gcc dot gnu dot org
- Date: Fri, 22 May 2009 06:58:11 +0900 (JST)
- Subject: [patch RFA] Backport "dbr_schedule vs uninitialized registers" patch
Hi,
PR rtl-optimization/40105 is a wrong code problem which is
a 4.3/4.4 regression for SH. In failing case, a delayed slot
for a branch is filled with an inappropriate instruction.
Fortunately, it's solved on trunk recently with the patch
dbr_schedule vs uninitialized registers (2)
http://gcc.gnu.org/ml/gcc-patches/2009-04/msg02097.html
and its follow-up
Re: Fix PR rtl-optimization/39938
http://gcc.gnu.org/ml/gcc-patches/2009-04/msg02381.html
With backporting these patches, the test case in the PR is
compiled correctly with 4.[34] compilers and gentoo folks
kindly confirm the original bootstrap issue on gentoo system
went away. I've attached the backported patches which are
tested with bootstrap and the top level "make -k check" on
i686-pc-linux-gnu and powerpc-apple-darwin9.5.0.
Are these patch OK for the 4.3/4.4 branches?
Regards,
kaz
--
PR rtl-optimization/40105
Backport from mainline:
2009-04-29 Eric Botcazou <ebotcazou@adacore.com>
Steven Bosscher <steven@gcc.gnu.org>
* Makefile.in (cfgrtl.o): Add $(INSN_ATTR_H).
* cfgrtl.c: Include insn-attr.h.
(rest_of_pass_free_cfg): New function.
(pass_free_cfg): Use rest_of_pass_free_cfg as execute function.
2009-04-27 Richard Sandiford <rdsandiford@googlemail.com>
Eric Botcazou <ebotcazou@adacore.com>
* resource.c (find_basic_block): Use BLOCK_FOR_INSN to look up
a label's basic block.
(mark_target_live_regs): Tidy and rework obsolete comments.
Change back DF problem to LIVE. If a label starts a basic block,
assume that all registers that used to be live then still are.
(init_resource_info): If a label starts a basic block, set its
BLOCK_FOR_INSN accordingly.
(free_resource_info): Undo the setting of BLOCK_FOR_INSN.
diff -uprN ORIG/gcc-4_3-branch/gcc/Makefile.in gcc-4_3-branch/gcc/Makefile.in
--- ORIG/gcc-4_3-branch/gcc/Makefile.in 2009-02-06 09:33:47.000000000 +0900
+++ gcc-4_3-branch/gcc/Makefile.in 2009-05-19 08:20:38.000000000 +0900
@@ -2664,7 +2664,8 @@ cfgexpand.o : cfgexpand.c $(TREE_FLOW_H)
value-prof.h
cfgrtl.o : cfgrtl.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) \
$(FLAGS_H) insn-config.h $(BASIC_BLOCK_H) $(REGS_H) hard-reg-set.h \
- output.h toplev.h $(FUNCTION_H) except.h $(TM_P_H) insn-config.h $(EXPR_H) \
+ output.h toplev.h $(FUNCTION_H) except.h $(TM_P_H) $(INSN_ATTR_H) \
+ insn-config.h $(EXPR_H) \
$(CFGLAYOUT_H) $(CFGLOOP_H) $(OBSTACK_H) $(TARGET_H) $(TREE_H) \
tree-pass.h $(DF_H)
cfganal.o : cfganal.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) \
diff -uprN ORIG/gcc-4_3-branch/gcc/cfgrtl.c gcc-4_3-branch/gcc/cfgrtl.c
--- ORIG/gcc-4_3-branch/gcc/cfgrtl.c 2008-02-20 06:48:52.000000000 +0900
+++ gcc-4_3-branch/gcc/cfgrtl.c 2009-05-14 08:15:13.000000000 +0900
@@ -53,6 +53,7 @@ along with GCC; see the file COPYING3.
#include "toplev.h"
#include "tm_p.h"
#include "obstack.h"
+#include "insn-attr.h"
#include "insn-config.h"
#include "cfglayout.h"
#include "expr.h"
@@ -427,11 +428,25 @@ free_bb_for_insn (void)
return 0;
}
+static unsigned int
+rest_of_pass_free_cfg (void)
+{
+#ifdef DELAY_SLOTS
+ /* The resource.c machinery uses DF but the CFG isn't guaranteed to be
+ valid at that point so it would be too late to call df_analyze. */
+ if (optimize > 0 && flag_delayed_branch)
+ df_analyze ();
+#endif
+
+ free_bb_for_insn ();
+ return 0;
+}
+
struct tree_opt_pass pass_free_cfg =
{
NULL, /* name */
NULL, /* gate */
- free_bb_for_insn, /* execute */
+ rest_of_pass_free_cfg, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
diff -uprN ORIG/gcc-4_3-branch/gcc/resource.c gcc-4_3-branch/gcc/resource.c
--- ORIG/gcc-4_3-branch/gcc/resource.c 2008-02-20 06:48:51.000000000 +0900
+++ gcc-4_3-branch/gcc/resource.c 2009-05-14 08:12:54.000000000 +0900
@@ -135,8 +135,6 @@ update_live_status (rtx dest, const_rtx
static int
find_basic_block (rtx insn, int search_limit)
{
- basic_block bb;
-
/* Scan backwards to the previous BARRIER. Then see if we can find a
label that starts a basic block. Return the basic block number. */
for (insn = prev_nonnote_insn (insn);
@@ -157,11 +155,8 @@ find_basic_block (rtx insn, int search_l
for (insn = next_nonnote_insn (insn);
insn && LABEL_P (insn);
insn = next_nonnote_insn (insn))
- {
- FOR_EACH_BB (bb)
- if (insn == BB_HEAD (bb))
- return bb->index;
- }
+ if (BLOCK_FOR_INSN (insn))
+ return BLOCK_FOR_INSN (insn)->index;
return -1;
}
@@ -851,13 +846,12 @@ return_insn_p (const_rtx insn)
(with no intervening active insns) to see if any of them start a basic
block. If we hit the start of the function first, we use block 0.
- Once we have found a basic block and a corresponding first insns, we can
- accurately compute the live status from basic_block_live_regs and
- reg_renumber. (By starting at a label following a BARRIER, we are immune
- to actions taken by reload and jump.) Then we scan all insns between
- that point and our target. For each CLOBBER (or for call-clobbered regs
- when we pass a CALL_INSN), mark the appropriate registers are dead. For
- a SET, mark them as live.
+ Once we have found a basic block and a corresponding first insn, we can
+ accurately compute the live status (by starting at a label following a
+ BARRIER, we are immune to actions taken by reload and jump.) Then we
+ scan all insns between that point and our target. For each CLOBBER (or
+ for call-clobbered regs when we pass a CALL_INSN), mark the appropriate
+ registers are dead. For a SET, mark them as live.
We have to be careful when using REG_DEAD notes because they are not
updated by such things as find_equiv_reg. So keep track of registers
@@ -957,13 +951,10 @@ mark_target_live_regs (rtx insns, rtx ta
TARGET. Otherwise, we must assume everything is live. */
if (b != -1)
{
- regset regs_live = DF_LR_IN (BASIC_BLOCK (b));
+ regset regs_live = df_get_live_in (BASIC_BLOCK (b));
rtx start_insn, stop_insn;
- /* Compute hard regs live at start of block -- this is the real hard regs
- marked live, plus live pseudo regs that have been renumbered to
- hard regs. */
-
+ /* Compute hard regs live at start of block. */
REG_SET_TO_HARD_REG_SET (current_live_regs, regs_live);
/* Get starting and ending insn, handling the case where each might
@@ -1049,10 +1040,24 @@ mark_target_live_regs (rtx insns, rtx ta
else if (LABEL_P (real_insn))
{
+ basic_block bb;
+
/* A label clobbers the pending dead registers since neither
reload nor jump will propagate a value across a label. */
AND_COMPL_HARD_REG_SET (current_live_regs, pending_dead_regs);
CLEAR_HARD_REG_SET (pending_dead_regs);
+
+ /* We must conservatively assume that all registers that used
+ to be live here still are. The fallthrough edge may have
+ left a live register uninitialized. */
+ bb = BLOCK_FOR_INSN (real_insn);
+ if (bb)
+ {
+ HARD_REG_SET extra_live;
+
+ REG_SET_TO_HARD_REG_SET (extra_live, df_get_live_in (bb));
+ IOR_HARD_REG_SET (current_live_regs, extra_live);
+ }
}
/* The beginning of the epilogue corresponds to the end of the
@@ -1124,6 +1129,7 @@ void
init_resource_info (rtx epilogue_insn)
{
int i;
+ basic_block bb;
/* Indicate what resources are required to be valid at the end of the current
function. The condition code never is and memory always is. If the
@@ -1192,6 +1198,11 @@ init_resource_info (rtx epilogue_insn)
/* Allocate and initialize the tables used by mark_target_live_regs. */
target_hash_table = XCNEWVEC (struct target_info *, TARGET_HASH_PRIME);
bb_ticks = XCNEWVEC (int, last_basic_block);
+
+ /* Set the BLOCK_FOR_INSN of each label that starts a basic block. */
+ FOR_EACH_BB (bb)
+ if (LABEL_P (BB_HEAD (bb)))
+ BLOCK_FOR_INSN (BB_HEAD (bb)) = bb;
}
/* Free up the resources allocated to mark_target_live_regs (). This
@@ -1200,6 +1211,8 @@ init_resource_info (rtx epilogue_insn)
void
free_resource_info (void)
{
+ basic_block bb;
+
if (target_hash_table != NULL)
{
int i;
@@ -1225,6 +1238,10 @@ free_resource_info (void)
free (bb_ticks);
bb_ticks = NULL;
}
+
+ FOR_EACH_BB (bb)
+ if (LABEL_P (BB_HEAD (bb)))
+ BLOCK_FOR_INSN (BB_HEAD (bb)) = NULL;
}
/* Clear any hashed information that we have stored for INSN. */
diff -uprN ORIG/gcc-4_4-branch/gcc/Makefile.in gcc-4_4-branch/gcc/Makefile.in
--- ORIG/gcc-4_4-branch/gcc/Makefile.in 2009-04-05 21:43:47.000000000 +0900
+++ gcc-4_4-branch/gcc/Makefile.in 2009-05-19 08:11:41.000000000 +0900
@@ -2785,7 +2785,8 @@ cfgexpand.o : cfgexpand.c $(TREE_FLOW_H)
value-prof.h $(TREE_INLINE_H) $(TARGET_H)
cfgrtl.o : cfgrtl.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) \
$(FLAGS_H) insn-config.h $(BASIC_BLOCK_H) $(REGS_H) hard-reg-set.h \
- output.h $(TOPLEV_H) $(FUNCTION_H) except.h $(TM_P_H) insn-config.h $(EXPR_H) \
+ output.h $(TOPLEV_H) $(FUNCTION_H) except.h $(TM_P_H) $(INSN_ATTR_H) \
+ insn-config.h $(EXPR_H) \
$(CFGLAYOUT_H) $(CFGLOOP_H) $(OBSTACK_H) $(TARGET_H) $(TREE_H) \
tree-pass.h $(DF_H) $(GGC_H)
cfganal.o : cfganal.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) \
diff -uprN ORIG/gcc-4_4-branch/gcc/cfgrtl.c gcc-4_4-branch/gcc/cfgrtl.c
--- ORIG/gcc-4_4-branch/gcc/cfgrtl.c 2009-04-05 21:43:47.000000000 +0900
+++ gcc-4_4-branch/gcc/cfgrtl.c 2009-05-19 08:13:48.000000000 +0900
@@ -53,6 +53,7 @@ along with GCC; see the file COPYING3.
#include "toplev.h"
#include "tm_p.h"
#include "obstack.h"
+#include "insn-attr.h"
#include "insn-config.h"
#include "cfglayout.h"
#include "expr.h"
@@ -427,13 +428,27 @@ free_bb_for_insn (void)
return 0;
}
+static unsigned int
+rest_of_pass_free_cfg (void)
+{
+#ifdef DELAY_SLOTS
+ /* The resource.c machinery uses DF but the CFG isn't guaranteed to be
+ valid at that point so it would be too late to call df_analyze. */
+ if (optimize > 0 && flag_delayed_branch)
+ df_analyze ();
+#endif
+
+ free_bb_for_insn ();
+ return 0;
+}
+
struct rtl_opt_pass pass_free_cfg =
{
{
RTL_PASS,
NULL, /* name */
NULL, /* gate */
- free_bb_for_insn, /* execute */
+ rest_of_pass_free_cfg, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
diff -uprN ORIG/gcc-4_4-branch/gcc/resource.c gcc-4_4-branch/gcc/resource.c
--- ORIG/gcc-4_4-branch/gcc/resource.c 2009-04-05 21:43:47.000000000 +0900
+++ gcc-4_4-branch/gcc/resource.c 2009-05-19 08:08:19.000000000 +0900
@@ -135,8 +135,6 @@ update_live_status (rtx dest, const_rtx
static int
find_basic_block (rtx insn, int search_limit)
{
- basic_block bb;
-
/* Scan backwards to the previous BARRIER. Then see if we can find a
label that starts a basic block. Return the basic block number. */
for (insn = prev_nonnote_insn (insn);
@@ -157,11 +155,8 @@ find_basic_block (rtx insn, int search_l
for (insn = next_nonnote_insn (insn);
insn && LABEL_P (insn);
insn = next_nonnote_insn (insn))
- {
- FOR_EACH_BB (bb)
- if (insn == BB_HEAD (bb))
- return bb->index;
- }
+ if (BLOCK_FOR_INSN (insn))
+ return BLOCK_FOR_INSN (insn)->index;
return -1;
}
@@ -848,13 +843,12 @@ return_insn_p (const_rtx insn)
(with no intervening active insns) to see if any of them start a basic
block. If we hit the start of the function first, we use block 0.
- Once we have found a basic block and a corresponding first insns, we can
- accurately compute the live status from basic_block_live_regs and
- reg_renumber. (By starting at a label following a BARRIER, we are immune
- to actions taken by reload and jump.) Then we scan all insns between
- that point and our target. For each CLOBBER (or for call-clobbered regs
- when we pass a CALL_INSN), mark the appropriate registers are dead. For
- a SET, mark them as live.
+ Once we have found a basic block and a corresponding first insn, we can
+ accurately compute the live status (by starting at a label following a
+ BARRIER, we are immune to actions taken by reload and jump.) Then we
+ scan all insns between that point and our target. For each CLOBBER (or
+ for call-clobbered regs when we pass a CALL_INSN), mark the appropriate
+ registers are dead. For a SET, mark them as live.
We have to be careful when using REG_DEAD notes because they are not
updated by such things as find_equiv_reg. So keep track of registers
@@ -954,13 +948,10 @@ mark_target_live_regs (rtx insns, rtx ta
TARGET. Otherwise, we must assume everything is live. */
if (b != -1)
{
- regset regs_live = DF_LR_IN (BASIC_BLOCK (b));
+ regset regs_live = df_get_live_in (BASIC_BLOCK (b));
rtx start_insn, stop_insn;
- /* Compute hard regs live at start of block -- this is the real hard regs
- marked live, plus live pseudo regs that have been renumbered to
- hard regs. */
-
+ /* Compute hard regs live at start of block. */
REG_SET_TO_HARD_REG_SET (current_live_regs, regs_live);
/* Get starting and ending insn, handling the case where each might
@@ -1046,10 +1037,24 @@ mark_target_live_regs (rtx insns, rtx ta
else if (LABEL_P (real_insn))
{
+ basic_block bb;
+
/* A label clobbers the pending dead registers since neither
reload nor jump will propagate a value across a label. */
AND_COMPL_HARD_REG_SET (current_live_regs, pending_dead_regs);
CLEAR_HARD_REG_SET (pending_dead_regs);
+
+ /* We must conservatively assume that all registers that used
+ to be live here still are. The fallthrough edge may have
+ left a live register uninitialized. */
+ bb = BLOCK_FOR_INSN (real_insn);
+ if (bb)
+ {
+ HARD_REG_SET extra_live;
+
+ REG_SET_TO_HARD_REG_SET (extra_live, df_get_live_in (bb));
+ IOR_HARD_REG_SET (current_live_regs, extra_live);
+ }
}
/* The beginning of the epilogue corresponds to the end of the
@@ -1121,6 +1126,7 @@ void
init_resource_info (rtx epilogue_insn)
{
int i;
+ basic_block bb;
/* Indicate what resources are required to be valid at the end of the current
function. The condition code never is and memory always is. If the
@@ -1189,6 +1195,11 @@ init_resource_info (rtx epilogue_insn)
/* Allocate and initialize the tables used by mark_target_live_regs. */
target_hash_table = XCNEWVEC (struct target_info *, TARGET_HASH_PRIME);
bb_ticks = XCNEWVEC (int, last_basic_block);
+
+ /* Set the BLOCK_FOR_INSN of each label that starts a basic block. */
+ FOR_EACH_BB (bb)
+ if (LABEL_P (BB_HEAD (bb)))
+ BLOCK_FOR_INSN (BB_HEAD (bb)) = bb;
}
/* Free up the resources allocated to mark_target_live_regs (). This
@@ -1197,6 +1208,8 @@ init_resource_info (rtx epilogue_insn)
void
free_resource_info (void)
{
+ basic_block bb;
+
if (target_hash_table != NULL)
{
int i;
@@ -1222,6 +1235,10 @@ free_resource_info (void)
free (bb_ticks);
bb_ticks = NULL;
}
+
+ FOR_EACH_BB (bb)
+ if (LABEL_P (BB_HEAD (bb)))
+ BLOCK_FOR_INSN (BB_HEAD (bb)) = NULL;
}
/* Clear any hashed information that we have stored for INSN. */