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author | Jakub Jelinek <jakub@redhat.com> | 2022-01-28 11:48:18 +0100 |
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committer | Jakub Jelinek <jakub@redhat.com> | 2022-01-28 11:48:18 +0100 |
commit | 430dca620fa3d03e53f6771a2b61d3f0ebb73756 (patch) | |
tree | d0b397f2abfddba856f1618a59d13f535dab98e8 /gcc | |
parent | b500d2591ea0080459d5dee127f63c010530f6b6 (diff) | |
download | gcc-430dca620fa3d03e53f6771a2b61d3f0ebb73756.zip gcc-430dca620fa3d03e53f6771a2b61d3f0ebb73756.tar.gz gcc-430dca620fa3d03e53f6771a2b61d3f0ebb73756.tar.bz2 |
cfgrtl: Fix up locus comparison in unique_locus_on_edge_between_p [PR104237]
The testcase in the PR (not included for the testsuite because we don't
have an (easy) way to -fcompare-debug LTO, we'd need 2 compilations/linking,
one with -g and one with -g0 and -fdump-rtl-final= at the end of lto1
and compare that) has different code generation for -g vs. -g0.
The difference appears during expansion, where we have a goto_locus
that is at -O0 compared to the INSN_LOCATION of the previous and next insn
across an edge. With -g0 the locations are equal and so no nop is added.
With -g the locations aren't equal and so a nop is added holding that
location.
The reason for the different location is in the way how we stream in
locations by lto1.
We have lto_location_cache::apply_location_cache that is called with some
set of expanded locations, qsorts them, creates location_t's for those
and remembers the last expanded location.
lto_location_cache::input_location_and_block when read in expanded_location
is equal to the last expanded location just reuses the last location_t
(or adds/changes/removes LOCATION_BLOCK in it), when it is not queues
it for next apply_location_cache. Now, when streaming in -g input, we can
see extra locations that don't appear with -g0, and if we are unlucky
enough, those can be sorted last during apply_location_cache and affect
what locations are used from the single entry cache next.
In particular, second apply_location_cache with non-empty loc_cache in
the testcase has 14 locations with -g0 and 16 with -g and those 2 extra
ones sort both last (they are the same). The last one from -g0 then
appears to be input_location_and_block sourced again, for -g0 triggers
the single entry cache, while for -g it doesn't and so apply_location_cache
will create for it another location_t with the same content.
The following patch fixes it by comparing everything we care about the
location instead (well, better in addition) to a simple location_t ==
location_t check. I think we don't care about the sysp flag for debug
info...
2022-01-28 Jakub Jelinek <jakub@redhat.com>
PR lto/104237
* cfgrtl.cc (loc_equal): New function.
(unique_locus_on_edge_between_p): Use it.
Diffstat (limited to 'gcc')
-rw-r--r-- | gcc/cfgrtl.cc | 27 |
1 files changed, 25 insertions, 2 deletions
diff --git a/gcc/cfgrtl.cc b/gcc/cfgrtl.cc index 9ccc65b..5675751 100644 --- a/gcc/cfgrtl.cc +++ b/gcc/cfgrtl.cc @@ -778,6 +778,29 @@ rtl_split_block (basic_block bb, void *insnp) return new_bb; } +/* Return true if LOC1 and LOC2 are equivalent for + unique_locus_on_edge_between_p purposes. */ + +static bool +loc_equal (location_t loc1, location_t loc2) +{ + if (loc1 == loc2) + return true; + + expanded_location loce1 = expand_location (loc1); + expanded_location loce2 = expand_location (loc2); + + if (loce1.line != loce2.line + || loce1.column != loce2.column + || loce1.data != loce2.data) + return false; + if (loce1.file == loce2.file) + return true; + return (loce1.file != NULL + && loce2.file != NULL + && filename_cmp (loce1.file, loce2.file) == 0); +} + /* Return true if the single edge between blocks A and B is the only place in RTL which holds some unique locus. */ @@ -796,7 +819,7 @@ unique_locus_on_edge_between_p (basic_block a, basic_block b) while (insn != end && (!NONDEBUG_INSN_P (insn) || !INSN_HAS_LOCATION (insn))) insn = PREV_INSN (insn); - if (insn != end && INSN_LOCATION (insn) == goto_locus) + if (insn != end && loc_equal (INSN_LOCATION (insn), goto_locus)) return false; /* Then scan block B forward. */ @@ -808,7 +831,7 @@ unique_locus_on_edge_between_p (basic_block a, basic_block b) insn = NEXT_INSN (insn); if (insn != end && INSN_HAS_LOCATION (insn) - && INSN_LOCATION (insn) == goto_locus) + && loc_equal (INSN_LOCATION (insn), goto_locus)) return false; } |