Thanks a lot for the review and comments.
I am on a short vacation this week. And will respond to all your questions
after I am back the end of this week.
Qing
> On May 19, 2025, at 06:44, Richard Biener <richard.guent...@gmail.com> wrote:
>
> On Fri, May 16, 2025 at 3:34 PM Qing Zhao <qing.z...@oracle.com> wrote:
>>
>> Control this with a new option -fdiagnostics-details.
>>
>> $ cat t.c
>> extern void warn(void);
>> static inline void assign(int val, int *regs, int *index)
>> {
>> if (*index >= 4)
>> warn();
>> *regs = val;
>> }
>> struct nums {int vals[4];};
>>
>> void sparx5_set (int *ptr, struct nums *sg, int index)
>> {
>> int *val = &sg->vals[index];
>>
>> assign(0, ptr, &index);
>> assign(*val, ptr, &index);
>> }
>>
>> $ gcc -Wall -O2 -c -o t.o t.c
>> t.c: In function ‘sparx5_set’:
>> t.c:12:23: warning: array subscript 4 is above array bounds of ‘int[4]’
>> [-Warray-bounds=]
>> 12 | int *val = &sg->vals[index];
>> | ~~~~~~~~^~~~~~~
>> t.c:8:18: note: while referencing ‘vals’
>> 8 | struct nums {int vals[4];};
>> | ^~~~
>>
>> In the above, Although the warning is correct in theory, the warning message
>> itself is confusing to the end-user since there is information that cannot
>> be connected to the source code directly.
>>
>> It will be a nice improvement to add more information in the warning message
>> to report where such index value come from.
>>
>> In order to achieve this, we add a new data structure "move_history" to
>> record
>> 1. the "condition" that triggers the code movement;
>> 2. whether the code movement is on the true path of the "condition";
>> 3. the "compiler transformation" that triggers the code movement.
>>
>> Whenever there is a code movement along control flow graph due to some
>> specific transformations, such as jump threading, path isolation, tree
>> sinking, etc., a move_history structure is created and attached to the
>> moved gimple statement.
>>
>> During array out-of-bound checking or -Wstringop-* warning checking, the
>> "move_history" that was attached to the gimple statement is used to form
>> a sequence of diagnostic events that are added to the corresponding rich
>> location to be used to report the warning message.
>>
>> This behavior is controled by the new option -fdiagnostics-details
>> which is off by default.
>>
>> With this change, by adding -fdiagnostics-details,
>> the warning message for the above testing case is now:
>>
>> $ gcc -Wall -O2 -fdiagnostics-details -c -o t.o t.c
>> t.c: In function ‘sparx5_set’:
>> t.c:12:23: warning: array subscript 4 is above array bounds of ‘int[4]’
>> [-Warray-bounds=]
>> 12 | int *val = &sg->vals[index];
>> | ~~~~~~~~^~~~~~~
>> ‘sparx5_set’: events 1-2
>> 4 | if (*index >= 4)
>> | ^
>> | |
>> | (1) when the condition is evaluated to true
>> ......
>> 12 | int *val = &sg->vals[index];
>> | ~~~~~~~~~~~~~~~
>> | |
>> | (2) out of array bounds here
>> t.c:8:18: note: while referencing ‘vals’
>> 8 | struct nums {int vals[4];};
>> | ^~~~
>>
>> The change was divided into 3 parts:
>>
>> Part 1: Add new data structure move_history, record move_history during
>> transformation;
>> Part 2: In warning analysis, Use the new move_history to form a rich
>> location with a sequence of events, to report more context info
>> of the warnings.
>> Part 3: Add debugging mechanism for move_history.
>
> Thanks for working on this. I'm pasting my review notes on [1/3] below.
>
>
> ove histories are allocated from a global obstack - it seems they are
> never released, just the association between stmt and history is
> eventually broken by remove_move_history? Do you have any statistics
> on the memory usage? Might be an interesting bit to dump with
> -fmem-report (the size of the obstack). Likewise the statistics
> on the hash-map are interesting.
>
> static bool
> +is_move_history_existed (location_t cond_location, bool is_true_path,
> + enum move_reason
>
> that's a bit of an odd name - 'move_history_exists_p'? What are
> we supposed to do on a duplicate? This is a linear search - how
> many do we accumulate in practice? Does it make sense to put a
> limit on the number of transforms we record?
>
> static gimple *
> +get_cond_stmt (edge entry, bool is_destination, bool *is_true_path)
> +{
>
> I don't quite understand the is_destination parameter, likewise
> for the two APIs using this function? Usually the control edge
> and the BB the stmt is in can be different from edge->dest, and
> I'd expect the callers to know, so I wonder why we would want to
> search here? In particular the use in path isolation for PHI
> arguments passes in the edge of the problematic PHI arg but
> the first reached gcond * might not be the full controlling
> condition when there is more than two PHI arguments. Not to
> mention a switch statement might also be the control stmt.
> While this can be extended in future I'd like the caller
> to compute the control dependence that's relevant - using
> an edge (or in future a vector of edges) is fine, it should
> be the edge outgoing from the control stmt.
>
> @opindex fdiagnostics-details
> +@item -fdiagnostics-details
>
> Not entirely happy with the name, we have -fdiagnostic-show-*
> options related to events, so maybe -fdiagnostic-show-details
> or -fdiagnostic-show-context?
>
> @@ -581,6 +582,8 @@ gsi_remove (gimple_stmt_iterator *i, bool
> remove_permanently)
> cfun->debug_marker_count--;
> require_eh_edge_purge = remove_stmt_from_eh_lp (stmt);
> gimple_remove_stmt_histograms (cfun, stmt);
> + if (get_move_history (stmt) != NULL)
> + remove_move_history (stmt);
>
> I'd say make remove_move_history cope with the stmt not being in the
> hash is better, so just call that function here, without get_*()
>
> @ -712,6 +756,19 @@ sink_code_in_bb (basic_block bb,
> virtual_operand_live &vop_live)
> bb->index, (gsi_bb (togsi))->index);
> }
>
> + /* Set the move history for the stmt that is sinked from BB to
> + gsi_bb (togsi). This stmt is on the path from BB to
> + gsi_bb (togsi). */
> + if (flag_diagnostics_details)
> + {
> + /* BB might not be the immediate predecessor of gsi_bb (togsi),
> + get the edge chain from BB to gsi_bb (togsi). */
> + auto_vec<edge> edge_chain = get_edge_chain (bb, gsi_bb (togsi));
> +
> + for (edge entry : edge_chain)
> + set_move_history_to_stmt (stmt, entry, true, MOVE_BY_SINK);
> + }
>
> so you represent a more complex control condition by a series of sinkings?
> I guess that's possible in this case at least. I'll note the
> get_edge_chain function seems to be quite simplistic and likely
> prone to record only a part of the sinkings.
>
> + /* Set the move history for all the stmts in both original and
> copied
> + basic blocks. The duplicated block will be the destination of
> the
> + incoming edge. */
> + if (flag_diagnostics_details)
> + {
> + set_move_history_to_stmts_in_bb (e->dest, e, false,
> + COPY_BY_THREAD_JUMP);
> + set_move_history_to_stmts_in_bb (rd->dup_blocks[0], e,
> + true, COPY_BY_THREAD_JUMP);
> + }
>
> I'm taking this one as example - why are we setting a move history
> on the not copied part? Shouldn't that be still within the original
> constraints / location? Otherwise why would(nt) we show the location
> and direction of all control stmts of a stmts we emit a diagnostic on?
>
>
> I think it makes sense to squash [3/3] into this patch.
>
> There is documentation about diagnostics in doc/ux.texi, it would be
> nice to mention move-history there.
>
>
> Thanks,
> Richard.
>
>> PR tree-optimization/109071
>> PR tree-optimization/85788
>> PR tree-optimization/88771
>> PR tree-optimization/106762
>> PR tree-optimization/108770
>> PR tree-optimization/115274
>> PR tree-optimization/117179
>>
>> gcc/ChangeLog:
>>
>> * Makefile.in (OBJS): Add diagnostic-move-history.o.
>> * gcc/common.opt (fdiagnostics-details): New option.
>> * gcc/doc/invoke.texi (fdiagnostics-details): Add
>> documentation for the new option.
>> * gimple-iterator.cc (gsi_remove): (gsi_remove): Remove the move
>> history when removing the gimple.
>> * gimple-pretty-print.cc (pp_gimple_stmt_1): Emit MV_H marking
>> if the gimple has a move_history.
>> * gimple-ssa-isolate-paths.cc (isolate_path): Set move history
>> for the gimples of the duplicated blocks.
>> * tree-ssa-sink.cc (sink_code_in_bb): Create move_history for
>> stmt when it is sinked.
>> * toplev.cc (toplev::finalize): Call move_history_finalize.
>> * tree-ssa-threadupdate.cc (ssa_redirect_edges): Create move_history
>> for stmts when they are duplicated.
>> (back_jt_path_registry::duplicate_thread_path): Likewise.
>> * diagnostic-move-history.cc: New file.
>> * diagnostic-move-history.h: New file.
>>
>> gcc/testsuite/ChangeLog:
>>
>> * gcc.dg/pr117375.c: New test.
>> ---
>> gcc/Makefile.in | 1 +
>> gcc/common.opt | 4 +
>> gcc/diagnostic-move-history.cc | 265 ++++++++++++++++++++++++++++++++
>> gcc/diagnostic-move-history.h | 92 +++++++++++
>> gcc/doc/invoke.texi | 11 ++
>> gcc/gimple-iterator.cc | 3 +
>> gcc/gimple-pretty-print.cc | 4 +
>> gcc/gimple-ssa-isolate-paths.cc | 11 ++
>> gcc/testsuite/gcc.dg/pr117375.c | 13 ++
>> gcc/toplev.cc | 3 +
>> gcc/tree-ssa-sink.cc | 57 +++++++
>> gcc/tree-ssa-threadupdate.cc | 25 +++
>> 12 files changed, 489 insertions(+)
>> create mode 100644 gcc/diagnostic-move-history.cc
>> create mode 100644 gcc/diagnostic-move-history.h
>> create mode 100644 gcc/testsuite/gcc.dg/pr117375.c
>>
>> diff --git a/gcc/Makefile.in b/gcc/Makefile.in
>> index 72d132207c0..38dfb688e60 100644
>> --- a/gcc/Makefile.in
>> +++ b/gcc/Makefile.in
>> @@ -1451,6 +1451,7 @@ OBJS = \
>> df-problems.o \
>> df-scan.o \
>> dfp.o \
>> + diagnostic-move-history.o \
>> digraph.o \
>> dojump.o \
>> dominance.o \
>> diff --git a/gcc/common.opt b/gcc/common.opt
>> index 0e50305dde8..081537c349a 100644
>> --- a/gcc/common.opt
>> +++ b/gcc/common.opt
>> @@ -1613,6 +1613,10 @@ fdiagnostics-minimum-margin-width=
>> Common Joined UInteger Var(diagnostics_minimum_margin_width) Init(6)
>> Set minimum width of left margin of source code when showing source.
>>
>> +fdiagnostics-details
>> +Common Var(flag_diagnostics_details)
>> +Collect and print more context information for diagnostics.
>> +
>> fdisable-
>> Common Joined RejectNegative Var(common_deferred_options) Defer
>> -fdisable-[tree|rtl|ipa]-<pass>=range1+range2 Disable an optimization pass.
>> diff --git a/gcc/diagnostic-move-history.cc b/gcc/diagnostic-move-history.cc
>> new file mode 100644
>> index 00000000000..83d8a42b577
>> --- /dev/null
>> +++ b/gcc/diagnostic-move-history.cc
>> @@ -0,0 +1,265 @@
>> +/* Functions to handle move history.
>> + Copyright (C) 2024 Free Software Foundation, Inc.
>> + Contributed by Qing Zhao <qing.z...@oracle.com>
>> +
>> + This file is part of GCC.
>> +
>> + GCC is free software; you can redistribute it and/or modify it under
>> + the terms of the GNU General Public License as published by the Free
>> + Software Foundation; either version 3, or (at your option) any later
>> + version.
>> +
>> + GCC is distributed in the hope that it will be useful, but WITHOUT ANY
>> + WARRANTY; without even the implied warranty of MERCHANTABILITY or
>> + FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
>> + for more details.
>> +
>> + You should have received a copy of the GNU General Public License
>> + along with GCC; see the file COPYING3. If not see
>> + <http://www.gnu.org/licenses/>. */
>> +
>> +#define INCLUDE_MEMORY
>> +#include "config.h"
>> +#include "system.h"
>> +#include "coretypes.h"
>> +#include "backend.h"
>> +#include "tree.h"
>> +#include "gimple.h"
>> +#include "gimple-iterator.h"
>> +#include "cfganal.h"
>> +#include "diagnostic-move-history.h"
>> +
>> +/* A mapping from a gimple to a pointer to the move history of it. */
>> +static move_history_map_t *move_history_map;
>> +
>> +/* Obstack for move history. */
>> +static struct obstack move_history_obstack;
>> +
>> +/* Create a new move history. */
>> +
>> +move_history_t
>> +create_move_history (location_t condition,
>> + bool is_true_path,
>> + enum move_reason reason,
>> + move_history_t prev_move)
>> +{
>> + static bool initialized = false;
>> +
>> + if (!initialized)
>> + {
>> + gcc_obstack_init (&move_history_obstack);
>> + initialized = true;
>> + }
>> +
>> + move_history_t move_history
>> + = (move_history_t) obstack_alloc (&move_history_obstack,
>> + sizeof (struct move_history));
>> + move_history->condition = condition;
>> + move_history->is_true_path = is_true_path;
>> + move_history->reason = reason;
>> + move_history->prev_move = prev_move;
>> + return move_history;
>> +}
>> +
>> +/* Insert the move history for the gimple STMT assuming the linked list
>> + of MV_HISTORY does not have duplications. It's the caller's
>> + responsibility to make sure that the linked list of MV_HISTORY does
>> + not have duplications. */
>> +
>> +void
>> +insert_move_history (gimple *stmt, move_history_t mv_history)
>> +{
>> + if (!move_history_map)
>> + move_history_map = new move_history_map_t;
>> +
>> + move_history_map->put (stmt, mv_history);
>> + return;
>> +}
>> +
>> +/* Get the move history for the gimple STMT, return NULL when there is
>> + no associated move history. */
>> +
>> +move_history_t
>> +get_move_history (const gimple *stmt)
>> +{
>> + if (!move_history_map)
>> + return NULL;
>> +
>> + if (const move_history_t *mv_history_p = move_history_map->get (stmt))
>> + return *mv_history_p;
>> +
>> + return NULL;
>> +}
>> +
>> +/* Remove the move history for STMT. */
>> +
>> +void
>> +remove_move_history (gimple *stmt)
>> +{
>> + if (!move_history_map)
>> + return;
>> + move_history_map->remove (stmt);
>> + return;
>> +}
>> +
>> +/* Check whether the cond_location, is_true_path and reason existed
>> + * in the OLD_MOVE_HISTORY. */
>> +
>> +static bool
>> +is_move_history_existed (location_t cond_location, bool is_true_path,
>> + enum move_reason reason,
>> + move_history_t old_move_history)
>> +{
>> + for (move_history_t cur_ch = old_move_history; cur_ch;
>> + cur_ch = cur_ch->prev_move)
>> + if ((cur_ch->condition == cond_location)
>> + && (cur_ch->is_true_path == is_true_path)
>> + && (cur_ch->reason == reason))
>> + return true;
>> +
>> + return false;
>> +}
>> +
>> +/* Set move history for the gimple STMT. Return TRUE when a new move
>> + * history is created and inserted. Otherwise return FALSE. */
>> +
>> +bool
>> +set_move_history (gimple *stmt, location_t cond_location,
>> + bool is_true_path, enum move_reason reason)
>> +{
>> +
>> + /* First, get the old move history associated with this STMT. */
>> + move_history_t old_mv_history = get_move_history (stmt);
>> +
>> + /* If the current move history is not in the STMT's move history linked
>> + list yet, create the new move history, put the old_move_history as the
>> + prev_move of it. */
>> + move_history_t new_mv_history = NULL;
>> + if (!is_move_history_existed (cond_location, is_true_path,
>> + reason, old_mv_history))
>> + new_mv_history
>> + = create_move_history (cond_location, is_true_path,
>> + reason, old_mv_history);
>> +
>> + /* Insert the move history into the hash map. */
>> + if (new_mv_history)
>> + {
>> + insert_move_history (stmt, new_mv_history);
>> + return true;
>> + }
>> +
>> + return false;
>> +}
>> +
>> +/* Reset all state for diagnostic-move-history.cc so that we can rerun the
>> + compiler within the same process. For use by toplev::finalize. */
>> +
>> +void
>> +move_history_finalize (void)
>> +{
>> + if (move_history_map)
>> + {
>> + delete move_history_map;
>> + move_history_map = NULL;
>> + }
>> + obstack_free (&move_history_obstack, NULL);
>> + return;
>> +}
>> +
>> +/* Given an edge ENTRY and whether the new code will be moved to the
>> + destination of the edge, IS_DISTINATION, return the condition
>> + statement in the source of the ENTRY if found. Return NULL otherwise.
>> +
>> + When the condition statement is found, setting IS_TRUE_PATH to true
>> + if the destination of the edge is on the true path of the condition.
>> +
>> + IS_TRUE_PATH is only valid when the condition statement is found.
>> +
>> + source
>> + | ENTRY
>> + V
>> + destination
>> +
>> +*/
>> +
>> +static gimple *
>> +get_cond_stmt (edge entry, bool is_destination, bool *is_true_path)
>> +{
>> + /* First, get the condition statement in the source of the
>> + edge ENTRY. */
>> + basic_block cond_block = entry->src;
>> + gimple *cond_stmt = NULL;
>> + gimple_stmt_iterator gsi;
>> + *is_true_path = false;
>> +
>> + /* if the cond_block ends with a conditional statement, get it. */
>> + while (!cond_stmt && cond_block)
>> + {
>> + gsi = gsi_last_bb (cond_block);
>> + if (!gsi_end_p (gsi)
>> + && gsi_stmt (gsi)
>> + && (gimple_code (gsi_stmt (gsi)) == GIMPLE_COND))
>> + cond_stmt = gsi_stmt (gsi);
>> + /* If there is no cond_stmt in the cond_block, search the single_pred
>> + of it. */
>> + if (!cond_stmt && single_pred_p (cond_block))
>> + {
>> + basic_block prev_cond_block = cond_block;
>> + cond_block = single_pred (cond_block);
>> + entry = find_edge (cond_block, prev_cond_block);
>> + }
>> + else
>> + break;
>> + }
>> +
>> + bool is_branch_taken = (cond_stmt && (BRANCH_EDGE (cond_block) == entry));
>> + *is_true_path = !(is_branch_taken ^ is_destination);
>> +
>> + return cond_stmt;
>> +}
>> +
>> +/* Set move history to the stmt based on the edge ENTRY and whether this
>> stmt
>> + will be in the destination of the ENTRY.
>> + The REASON indicates what kind of transformation contributing to the
>> + statment movement. Return TRUE when the move history has been set
>> + successfully. */
>> +
>> +bool
>> +set_move_history_to_stmt (gimple *stmt, edge entry,
>> + bool is_destination, enum move_reason reason)
>> +{
>> + bool is_true_path = false;
>> + gimple *cond_stmt = get_cond_stmt (entry, is_destination, &is_true_path);
>> +
>> + if (!cond_stmt)
>> + return false;
>> +
>> + set_move_history (stmt, gimple_location (cond_stmt),
>> + is_true_path, reason);
>> + return true;
>> +}
>> +
>> +/* Set move history to all the stmts in the basic block BB based on
>> + the edge ENTRY and whether this basic block will be the destination
>> + of the ENTRY.
>> + The REASON indicates what kind of transformation contributing to the
>> + statement move. Return TRUE when the move history has been set
>> + successfully. */
>> +
>> +bool
>> +set_move_history_to_stmts_in_bb (basic_block bb, edge entry,
>> + bool is_destination,
>> + enum move_reason reason)
>> +{
>> + bool is_true_path = false;
>> + gimple_stmt_iterator gsi;
>> + gimple *cond_stmt = get_cond_stmt (entry, is_destination, &is_true_path);
>> +
>> + if (!cond_stmt)
>> + return false;
>> + for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
>> + set_move_history (gsi_stmt (gsi), gimple_location (cond_stmt),
>> + is_true_path, reason);
>> +
>> + return true;
>> +}
>> diff --git a/gcc/diagnostic-move-history.h b/gcc/diagnostic-move-history.h
>> new file mode 100644
>> index 00000000000..9a58766d544
>> --- /dev/null
>> +++ b/gcc/diagnostic-move-history.h
>> @@ -0,0 +1,92 @@
>> +/* Move history associated with a gimple statement to record its history
>> + of movement due to different transformations.
>> + The move history will be used to construct events for later diagnostic.
>> +
>> + Copyright (C) 2024 Free Software Foundation, Inc.
>> + Contributed by Qing Zhao <qing.z...@oracle.com>
>> +
>> + This file is part of GCC.
>> +
>> + GCC is free software; you can redistribute it and/or modify it under
>> + the terms of the GNU General Public License as published by the Free
>> + Software Foundation; either version 3, or (at your option) any later
>> + version.
>> +
>> + GCC is distributed in the hope that it will be useful, but WITHOUT ANY
>> + WARRANTY; without even the implied warranty of MERCHANTABILITY or
>> + FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
>> + for more details.
>> +
>> + You should have received a copy of the GNU General Public License
>> + along with GCC; see the file COPYING3. If not see
>> + <http://www.gnu.org/licenses/>. */
>> +
>> +#ifndef DIAGNOSTIC_MOVE_HISTORY_H
>> +#define DIAGNOSTIC_MOVE_HISTORY_H
>> +
>> +#include "hash-map.h"
>> +#include "line-map.h"
>> +
>> +/* An enum for the reason why this move is made. Right now, there are
>> + three reasons, we can add more if needed. */
>> +enum move_reason {
>> + COPY_BY_THREAD_JUMP,
>> + COPY_BY_ISOLATE_PATH,
>> + MOVE_BY_SINK,
>> + COPY_BY_MAX
>> +};
>> +
>> +/* This data structure records the information when a statement is
>> + moved along control flow graph during different transformations.
>> + Such information will be used by the later diagnostic messages
>> + to report more contexts of the warnings or errors. */
>> +struct move_history {
>> + /* The location of the condition statement that triggered the code
>> + movement. */
>> + location_t condition;
>> +
>> + /* Whether this move is on the TRUE path of the condition. */
>> + bool is_true_path;
>> +
>> + /* The reason for the code movement. */
>> + enum move_reason reason;
>> +
>> + /* This statement itself might be a previous code movement. */
>> + struct move_history *prev_move;
>> +};
>> +
>> +typedef struct move_history *move_history_t;
>> +
>> +/* Create a new move history. */
>> +extern move_history_t create_move_history (location_t, bool,
>> + enum move_reason, move_history_t);
>> +
>> +typedef hash_map<const gimple *, move_history_t> move_history_map_t;
>> +
>> +/* Get the move history for the gimple STMT, return NULL when there is
>> + no associated move history. */
>> +extern move_history_t get_move_history (const gimple *);
>> +
>> +/* Remove the move history for STMT from the move_history_map. */
>> +extern void remove_move_history (gimple *);
>> +
>> +/* Set move history for the gimple STMT. */
>> +extern bool set_move_history (gimple *, location_t,
>> + bool, enum move_reason);
>> +
>> +/* Reset all state for diagnostic-move-history.cc so that we can rerun the
>> + compiler within the same process. For use by toplev::finalize. */
>> +extern void move_history_finalize (void);
>> +
>> +/* Set move history to the stmt based on the edge ENTRY and whether this
>> stmt
>> + will be in the destination of the ENTRY. */
>> +extern bool set_move_history_to_stmt (gimple *, edge,
>> + bool, enum move_reason);
>> +
>> +/* Set move history to all the stmts in the basic block based on
>> + the entry edge and whether this basic block will be the destination
>> + of the entry edge. */
>> +extern bool set_move_history_to_stmts_in_bb (basic_block, edge,
>> + bool, enum move_reason);
>> +
>> +#endif // DIAGNOSTIC_MOVE_HISTORY_H
>> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
>> index ee7180110e1..ca04f35d6a1 100644
>> --- a/gcc/doc/invoke.texi
>> +++ b/gcc/doc/invoke.texi
>> @@ -332,6 +332,7 @@ Objective-C and Objective-C++ Dialects}.
>> -fdiagnostics-column-origin=@var{origin}
>> -fdiagnostics-escape-format=@r{[}unicode@r{|}bytes@r{]}
>> -fdiagnostics-text-art-charset=@r{[}none@r{|}ascii@r{|}unicode@r{|}emoji@r{]}}
>> +-fdiagnostics-details
>>
>> @item Warning Options
>> @xref{Warning Options,,Options to Request or Suppress Warnings}.
>> @@ -5687,6 +5688,16 @@ left margin.
>> This option controls the minimum width of the left margin printed by
>> @option{-fdiagnostics-show-line-numbers}. It defaults to 6.
>>
>> +@opindex fdiagnostics-details
>> +@item -fdiagnostics-details
>> +With this option, the compiler collects more context information for
>> +diagnostics and emits them to the users to provide more hints on how
>> +the diagnostics come from, at the cost of a slightly slower compilation.
>> +Currently, The list of the impacted warning options includes:
>> +@option{-Warray-bounds}, @option{-Wstringop-overflow},
>> +@option{-Wstringop-overread}, and @option{-Wstringop-truncation}.
>> +More warning options might be added to this list in future releases.
>> +
>> @opindex fdiagnostics-parseable-fixits
>> @item -fdiagnostics-parseable-fixits
>> Emit fix-it hints in a machine-parseable format, suitable for consumption
>> diff --git a/gcc/gimple-iterator.cc b/gcc/gimple-iterator.cc
>> index 3af672bf0b9..f1d7ca9c78e 100644
>> --- a/gcc/gimple-iterator.cc
>> +++ b/gcc/gimple-iterator.cc
>> @@ -33,6 +33,7 @@ along with GCC; see the file COPYING3. If not see
>> #include "tree-ssa.h"
>> #include "value-prof.h"
>> #include "gimplify.h"
>> +#include "diagnostic-move-history.h"
>>
>>
>> /* Mark the statement STMT as modified, and update it. */
>> @@ -581,6 +582,8 @@ gsi_remove (gimple_stmt_iterator *i, bool
>> remove_permanently)
>> cfun->debug_marker_count--;
>> require_eh_edge_purge = remove_stmt_from_eh_lp (stmt);
>> gimple_remove_stmt_histograms (cfun, stmt);
>> + if (get_move_history (stmt) != NULL)
>> + remove_move_history (stmt);
>> }
>>
>> /* Update the iterator and re-wire the links in I->SEQ. */
>> diff --git a/gcc/gimple-pretty-print.cc b/gcc/gimple-pretty-print.cc
>> index 4e20b4cc371..811164565bb 100644
>> --- a/gcc/gimple-pretty-print.cc
>> +++ b/gcc/gimple-pretty-print.cc
>> @@ -44,6 +44,7 @@ along with GCC; see the file COPYING3. If not see
>> #include "asan.h"
>> #include "cfgloop.h"
>> #include "gimple-range.h"
>> +#include "diagnostic-move-history.h"
>>
>> /* Disable warnings about quoting issues in the pp_xxx calls below
>> that (intentionally) don't follow GCC diagnostic conventions. */
>> @@ -2734,6 +2735,9 @@ pp_gimple_stmt_1 (pretty_printer *pp, const gimple
>> *gs, int spc,
>> && (flags & TDF_ALIAS))
>> dump_ssaname_info (pp, gimple_get_lhs (gs), spc);
>>
>> + if (get_move_history (gs))
>> + pp_printf (pp, "[MV_H] ");
>> +
>> switch (gimple_code (gs))
>> {
>> case GIMPLE_ASM:
>> diff --git a/gcc/gimple-ssa-isolate-paths.cc
>> b/gcc/gimple-ssa-isolate-paths.cc
>> index ca1daf1d168..14c86590b17 100644
>> --- a/gcc/gimple-ssa-isolate-paths.cc
>> +++ b/gcc/gimple-ssa-isolate-paths.cc
>> @@ -37,6 +37,7 @@ along with GCC; see the file COPYING3. If not see
>> #include "tree-cfg.h"
>> #include "cfganal.h"
>> #include "intl.h"
>> +#include "diagnostic-move-history.h"
>>
>>
>> static bool cfg_altered;
>> @@ -170,6 +171,16 @@ isolate_path (basic_block bb, basic_block duplicate,
>> }
>> bb->count -= count;
>>
>> + /* Set the move history for all the stmts in both original and copied
>> + basic blocks. The duplicated block will be the destination of the
>> + incoming edge. */
>> + if (flag_diagnostics_details)
>> + {
>> + set_move_history_to_stmts_in_bb (bb, e, false, COPY_BY_ISOLATE_PATH);
>> + set_move_history_to_stmts_in_bb (duplicate, e,
>> + true, COPY_BY_ISOLATE_PATH);
>> + }
>> +
>> /* Complete the isolation step by redirecting E to reach DUPLICATE. */
>> e2 = redirect_edge_and_branch (e, duplicate);
>> if (e2)
>> diff --git a/gcc/testsuite/gcc.dg/pr117375.c
>> b/gcc/testsuite/gcc.dg/pr117375.c
>> new file mode 100644
>> index 00000000000..beb685afc3b
>> --- /dev/null
>> +++ b/gcc/testsuite/gcc.dg/pr117375.c
>> @@ -0,0 +1,13 @@
>> +/* PR middle-end/117375 ICE with -fdiagnostics-details patch in sink pass.
>> */
>> +/* { dg-do compile }
>> + { dg-options "-O2 -Wall -fdiagnostics-details" } */
>> +
>> +int st, st_0;
>> +int nbFilledBytes, max;
>> +void ec_enc_shrink();
>> +void max_allowed() {
>> + int nbAvailableBytes = nbFilledBytes;
>> + if (st && st_0)
>> + if (max < nbAvailableBytes)
>> + ec_enc_shrink();
>> +}
>> diff --git a/gcc/toplev.cc b/gcc/toplev.cc
>> index 7e457b5168b..7652c222676 100644
>> --- a/gcc/toplev.cc
>> +++ b/gcc/toplev.cc
>> @@ -42,6 +42,7 @@ along with GCC; see the file COPYING3. If not see
>> #include "coverage.h"
>> #include "diagnostic.h"
>> #include "pretty-print-urlifier.h"
>> +#include "diagnostic-move-history.h"
>> #include "varasm.h"
>> #include "tree-inline.h"
>> #include "realmpfr.h" /* For GMP/MPFR/MPC versions, in print_version. */
>> @@ -2436,6 +2437,8 @@ toplev::finalize (void)
>> reginfo_cc_finalize ();
>> varasm_cc_finalize ();
>>
>> + move_history_finalize ();
>> +
>> /* save_decoded_options uses opts_obstack, so these must
>> be cleaned up together. */
>> obstack_free (&opts_obstack, NULL);
>> diff --git a/gcc/tree-ssa-sink.cc b/gcc/tree-ssa-sink.cc
>> index 959e0d5c6be..0b3441e894c 100644
>> --- a/gcc/tree-ssa-sink.cc
>> +++ b/gcc/tree-ssa-sink.cc
>> @@ -37,6 +37,7 @@ along with GCC; see the file COPYING3. If not see
>> #include "tree-eh.h"
>> #include "tree-ssa-live.h"
>> #include "tree-dfa.h"
>> +#include "diagnostic-move-history.h"
>>
>> /* TODO:
>> 1. Sinking store only using scalar promotion (IE without moving the RHS):
>> @@ -655,6 +656,49 @@ sink_common_stores_to_bb (basic_block bb)
>> return todo;
>> }
>>
>> +/* Get the edge chain from FROM_BB to TO_BB, FROM_BB dominates TO_BB.
>> + B2
>> + / \
>> + V \
>> + B3 \
>> + / \ \
>> + V \---->V
>> + B4 B7
>> +
>> + In the above CFG, FROM_BB is B2, TO_BB is B4. This routine
>> + will locate two edges, B2->B3, and B3->B4 and return a vector
>> + with these two edges.
>> + This routine will return an empty vector if the control flow
>> + edge chain from FROM_BB to TO_BB is too complicate. */
>> +
>> +static auto_vec<edge>
>> +get_edge_chain (basic_block from_bb, basic_block to_bb)
>> +{
>> + auto_vec<edge> rev_edge_chain, edge_chain;
>> + basic_block imm_dom_bb;
>> + edge e;
>> + unsigned int i;
>> + /* Backtracing from TO_BB to FROM_BB through the dominator tree. */
>> + do
>> + {
>> + imm_dom_bb = get_immediate_dominator (CDI_DOMINATORS, to_bb);
>> + if (!imm_dom_bb)
>> + return edge_chain;
>> + e = find_edge (imm_dom_bb, to_bb);
>> + if (!e)
>> + return edge_chain;
>> + gcc_assert (e);
>> + rev_edge_chain.safe_push (e);
>> + to_bb = imm_dom_bb;
>> + }
>> + while (imm_dom_bb != from_bb);
>> +
>> + /* The order of the edges need to be reverted. */
>> + FOR_EACH_VEC_ELT_REVERSE (rev_edge_chain, i, e)
>> + edge_chain.safe_push (e);
>> + return edge_chain;
>> +}
>> +
>> /* Perform code sinking on BB */
>>
>> static unsigned
>> @@ -712,6 +756,19 @@ sink_code_in_bb (basic_block bb, virtual_operand_live
>> &vop_live)
>> bb->index, (gsi_bb (togsi))->index);
>> }
>>
>> + /* Set the move history for the stmt that is sinked from BB to
>> + gsi_bb (togsi). This stmt is on the path from BB to
>> + gsi_bb (togsi). */
>> + if (flag_diagnostics_details)
>> + {
>> + /* BB might not be the immediate predecessor of gsi_bb (togsi),
>> + get the edge chain from BB to gsi_bb (togsi). */
>> + auto_vec<edge> edge_chain = get_edge_chain (bb, gsi_bb (togsi));
>> +
>> + for (edge entry : edge_chain)
>> + set_move_history_to_stmt (stmt, entry, true, MOVE_BY_SINK);
>> + }
>> +
>> /* Update virtual operands of statements in the path we
>> do not sink to. */
>> if (gimple_vdef (stmt))
>> diff --git a/gcc/tree-ssa-threadupdate.cc b/gcc/tree-ssa-threadupdate.cc
>> index 4e5c7566857..789ca1d9422 100644
>> --- a/gcc/tree-ssa-threadupdate.cc
>> +++ b/gcc/tree-ssa-threadupdate.cc
>> @@ -36,6 +36,7 @@ along with GCC; see the file COPYING3. If not see
>> #include "tree-cfg.h"
>> #include "tree-vectorizer.h"
>> #include "tree-pass.h"
>> +#include "diagnostic-move-history.h"
>>
>> /* Given a block B, update the CFG and SSA graph to reflect redirecting
>> one or more in-edges to B to instead reach the destination of an
>> @@ -1341,6 +1342,17 @@ ssa_redirect_edges (struct redirection_data **slot,
>> {
>> edge e2;
>>
>> + /* Set the move history for all the stmts in both original and
>> copied
>> + basic blocks. The duplicated block will be the destination of
>> the
>> + incoming edge. */
>> + if (flag_diagnostics_details)
>> + {
>> + set_move_history_to_stmts_in_bb (e->dest, e, false,
>> + COPY_BY_THREAD_JUMP);
>> + set_move_history_to_stmts_in_bb (rd->dup_blocks[0], e,
>> + true, COPY_BY_THREAD_JUMP);
>> + }
>> +
>> if (dump_file && (dump_flags & TDF_DETAILS))
>> fprintf (dump_file, " Threaded jump %d --> %d to %d\n",
>> e->src->index, e->dest->index, rd->dup_blocks[0]->index);
>> @@ -2419,6 +2431,19 @@ back_jt_path_registry::duplicate_thread_path (edge
>> entry,
>> copy_bbs (region, n_region, region_copy, &exit, 1, &exit_copy, loop,
>> split_edge_bb_loc (entry), false);
>>
>> + /* Set the move history for all the stmts in both original and copied
>> + basic blocks. The copied regions will be the destination of the
>> + entry edge. */
>> + for (i = 0; i < n_region; i++)
>> + if (flag_diagnostics_details)
>> + {
>> + set_move_history_to_stmts_in_bb (region[i], entry, false,
>> + COPY_BY_THREAD_JUMP);
>> + set_move_history_to_stmts_in_bb (region_copy[i], entry,
>> + true, COPY_BY_THREAD_JUMP);
>> + }
>> +
>> +
>> /* Fix up: copy_bbs redirects all edges pointing to copied blocks. The
>> following code ensures that all the edges exiting the jump-thread path
>> are
>> redirected back to the original code: these edges are exceptions
>> --
>> 2.31.1
