Hi.
This fixes some implementations mistakes in sbitmap.c (bitmap_bit_in_range_p).
There's reference
to implementation one can take inspiration from:
https://www.cs.umd.edu/class/sum2003/cmsc311/Notes/BitOp/bitRange.html
Problem with our implementation is that one can't do:
(SBITMAP_ELT_TYPE)1 << SBITMAP_ELT_BITS (that would overflow)
Thus I do conditionally ~(SBITMAP_ELT_TYPE)0 at some places in the code.
I also added quite some unit tests for the method. But another questions pop up:
1) there are missing boundary asserts (or checking asserts) in sbitmap.c
2) we should probably include test-cases also for other functions
I can work on that (probably later) if desired?
And my patch breaks ssa-dse-26.c test-case, because now it properly returns
true for:
#0 bitmap_bit_in_range_p (bmap=0x21c4940, start=0, end=8) at
../../gcc/sbitmap.c:326
#1 0x0000000000d618f5 in live_bytes_read (use_ref=..., ref=0x7fffffffd480,
live=0x21c4940) at ../../gcc/tree-ssa-dse.c:496
#2 0x0000000000d61c4d in dse_classify_store (ref=0x7fffffffd480,
stmt=0x155553ea7d70, use_stmt=0x7fffffffd470, byte_tracking_enabled=true,
live_bytes=0x21c4940) at ../../gcc/tree-ssa-dse.c:594
#3 0x0000000000d6235b in dse_dom_walker::dse_optimize_stmt
(this=0x7fffffffd5c0, gsi=0x7fffffffd530) at ../../gcc/tree-ssa-dse.c:820
#4 0x0000000000d62461 in dse_dom_walker::before_dom_children
(this=0x7fffffffd5c0, bb=0x155553d76270) at ../../gcc/tree-ssa-dse.c:852
#5 0x00000000013b1698 in dom_walker::walk (this=0x7fffffffd5c0,
bb=0x155553d76270) at ../../gcc/domwalk.c:308
#6 0x0000000000d625ac in (anonymous namespace)::pass_dse::execute
(this=0x21d58c0, fun=0x155553eac0b0) at ../../gcc/tree-ssa-dse.c:906
#7 0x0000000000b27441 in execute_one_pass (pass=pass@entry=0x21d58c0) at
../../gcc/passes.c:2495
#8 0x0000000000b27d01 in execute_pass_list_1 (pass=0x21d58c0) at
../../gcc/passes.c:2584
#9 0x0000000000b27d13 in execute_pass_list_1 (pass=0x21d5480) at
../../gcc/passes.c:2585
#10 0x0000000000b27d55 in execute_pass_list (fn=<optimized out>,
pass=<optimized out>) at ../../gcc/passes.c:2595
#11 0x0000000000b26681 in do_per_function_toporder
(callback=callback@entry=0xb27d40 <execute_pass_list(function*, opt_pass*)>,
data=0x21d5300) at ../../gcc/passes.c:1737
#12 0x0000000000b283d7 in execute_ipa_pass_list (pass=0x21d52a0) at
../../gcc/passes.c:2935
#13 0x00000000007d29d2 in ipa_passes () at ../../gcc/cgraphunit.c:2399
#14 symbol_table::compile (this=this@entry=0x155553d6e100) at
../../gcc/cgraphunit.c:2534
#15 0x00000000007d5277 in symbol_table::compile (this=0x155553d6e100) at
../../gcc/cgraphunit.c:2695
#16 symbol_table::finalize_compilation_unit (this=0x155553d6e100) at
../../gcc/cgraphunit.c:2692
#17 0x0000000000c118ac in compile_file () at ../../gcc/toplev.c:481
#18 0x0000000000c13eee in do_compile () at ../../gcc/toplev.c:2037
#19 0x0000000000c141da in toplev::main (this=0x7fffffffd85e, argc=21,
argv=0x7fffffffd958) at ../../gcc/toplev.c:2172
#20 0x000000000061aeab in main (argc=21, argv=0x7fffffffd958) at
../../gcc/main.c:39
(gdb) p debug(bmap)
n_bits = 256, set = {8 9 10 11 12 13 14 15 }
Jeff can you please help me?
Apart from that the patch can bootstrap on ppc64le-redhat-linux and survives
regression tests.
Ready to be installed?
Martin
Thanks,
Martin
gcc/ChangeLog:
2017-10-10 Martin Liska <mli...@suse.cz>
PR tree-optimization/82493
* sbitmap.c (bitmap_bit_in_range_p): Fix the implementation.
(test_range_functions): New function.
(sbitmap_c_tests): Likewise.
* selftest-run-tests.c (selftest::run_tests): Run new tests.
* selftest.h (sbitmap_c_tests): New function.
---
gcc/sbitmap.c | 118 ++++++++++++++++++++++++++++++++++++++++-------
gcc/selftest-run-tests.c | 1 +
gcc/selftest.h | 1 +
3 files changed, 103 insertions(+), 17 deletions(-)
diff --git a/gcc/sbitmap.c b/gcc/sbitmap.c
index 4bf13a11a1d..baef4d05f0d 100644
--- a/gcc/sbitmap.c
+++ b/gcc/sbitmap.c
@@ -21,6 +21,7 @@ along with GCC; see the file COPYING3. If not see
#include "system.h"
#include "coretypes.h"
#include "sbitmap.h"
+#include "selftest.h"
typedef SBITMAP_ELT_TYPE *sbitmap_ptr;
typedef const SBITMAP_ELT_TYPE *const_sbitmap_ptr;
@@ -322,29 +323,22 @@ bitmap_set_range (sbitmap bmap, unsigned int start, unsigned int count)
bool
bitmap_bit_in_range_p (const_sbitmap bmap, unsigned int start, unsigned int end)
{
+ gcc_checking_assert (start <= end);
unsigned int start_word = start / SBITMAP_ELT_BITS;
unsigned int start_bitno = start % SBITMAP_ELT_BITS;
- /* Testing within a word, starting at the beginning of a word. */
- if (start_bitno == 0 && (end - start) < SBITMAP_ELT_BITS)
- {
- SBITMAP_ELT_TYPE mask = ((SBITMAP_ELT_TYPE)1 << (end - start)) - 1;
- return (bmap->elms[start_word] & mask) != 0;
- }
-
unsigned int end_word = end / SBITMAP_ELT_BITS;
unsigned int end_bitno = end % SBITMAP_ELT_BITS;
- /* Testing starts somewhere in the middle of a word. Test up to the
- end of the word or the end of the requested region, whichever comes
- first. */
+ /* Check beginning of first word if different from zero. */
if (start_bitno != 0)
{
- unsigned int nbits = ((start_word == end_word)
- ? end_bitno - start_bitno
- : SBITMAP_ELT_BITS - start_bitno);
- SBITMAP_ELT_TYPE mask = ((SBITMAP_ELT_TYPE)1 << nbits) - 1;
- mask <<= start_bitno;
+ SBITMAP_ELT_TYPE high_mask = ~(SBITMAP_ELT_TYPE)0;
+ if (start_word == end_word && end_bitno + 1 < SBITMAP_ELT_BITS)
+ high_mask = ((SBITMAP_ELT_TYPE)1 << (end_bitno + 1)) - 1;
+
+ SBITMAP_ELT_TYPE low_mask = ((SBITMAP_ELT_TYPE)1 << start_bitno) - 1;
+ SBITMAP_ELT_TYPE mask = high_mask - low_mask;
if (bmap->elms[start_word] & mask)
return true;
start_word++;
@@ -364,8 +358,9 @@ bitmap_bit_in_range_p (const_sbitmap bmap, unsigned int start, unsigned int end)
}
/* Now handle residuals in the last word. */
- SBITMAP_ELT_TYPE mask
- = ((SBITMAP_ELT_TYPE)1 << (SBITMAP_ELT_BITS - end_bitno)) - 1;
+ SBITMAP_ELT_TYPE mask = ~(SBITMAP_ELT_TYPE)0;
+ if (end_bitno + 1 < SBITMAP_ELT_BITS)
+ mask = ((SBITMAP_ELT_TYPE)1 << (end_bitno + 1)) - 1;
return (bmap->elms[start_word] & mask) != 0;
}
@@ -821,3 +816,92 @@ dump_bitmap_vector (FILE *file, const char *title, const char *subtitle,
fprintf (file, "\n");
}
+
+#if CHECKING_P
+
+namespace selftest {
+
+/* Selftests for sbitmaps. */
+
+
+/* Verify range functions for sbitmap. */
+
+static void
+test_range_functions ()
+{
+ sbitmap s = sbitmap_alloc (1024);
+ bitmap_clear (s);
+
+ ASSERT_FALSE (bitmap_bit_in_range_p (s, 512, 1023));
+ bitmap_set_bit (s, 100);
+
+ ASSERT_FALSE (bitmap_bit_in_range_p (s, 512, 1023));
+ ASSERT_FALSE (bitmap_bit_in_range_p (s, 0, 99));
+ ASSERT_FALSE (bitmap_bit_in_range_p (s, 101, 1023));
+ ASSERT_TRUE (bitmap_bit_in_range_p (s, 1, 100));
+ ASSERT_TRUE (bitmap_bit_in_range_p (s, 64, 100));
+ ASSERT_TRUE (bitmap_bit_in_range_p (s, 100, 100));
+ ASSERT_TRUE (bitmap_bit_p (s, 100));
+
+ s = sbitmap_alloc (64);
+ bitmap_clear (s);
+ bitmap_set_bit (s, 63);
+ ASSERT_TRUE (bitmap_bit_in_range_p (s, 0, 63));
+ ASSERT_TRUE (bitmap_bit_in_range_p (s, 1, 63));
+ ASSERT_TRUE (bitmap_bit_in_range_p (s, 63, 63));
+ ASSERT_TRUE (bitmap_bit_p (s, 63));
+
+ s = sbitmap_alloc (1024);
+ bitmap_clear (s);
+ bitmap_set_bit (s, 128);
+ ASSERT_FALSE (bitmap_bit_in_range_p (s, 0, 127));
+ ASSERT_FALSE (bitmap_bit_in_range_p (s, 129, 1023));
+
+ ASSERT_TRUE (bitmap_bit_in_range_p (s, 0, 128));
+ ASSERT_TRUE (bitmap_bit_in_range_p (s, 1, 128));
+ ASSERT_TRUE (bitmap_bit_in_range_p (s, 128, 255));
+ ASSERT_TRUE (bitmap_bit_in_range_p (s, 128, 254));
+ ASSERT_TRUE (bitmap_bit_p (s, 128));
+
+ bitmap_clear (s);
+ bitmap_set_bit (s, 8);
+ ASSERT_TRUE (bitmap_bit_in_range_p (s, 0, 8));
+ ASSERT_TRUE (bitmap_bit_in_range_p (s, 0, 12));
+ ASSERT_TRUE (bitmap_bit_in_range_p (s, 0, 63));
+ ASSERT_TRUE (bitmap_bit_in_range_p (s, 0, 127));
+ ASSERT_TRUE (bitmap_bit_in_range_p (s, 0, 512));
+ ASSERT_TRUE (bitmap_bit_in_range_p (s, 8, 8));
+ ASSERT_TRUE (bitmap_bit_p (s, 8));
+
+ bitmap_clear (s);
+ ASSERT_FALSE (bitmap_bit_in_range_p (s, 0, 0));
+ ASSERT_FALSE (bitmap_bit_in_range_p (s, 0, 8));
+ ASSERT_FALSE (bitmap_bit_in_range_p (s, 0, 63));
+ ASSERT_FALSE (bitmap_bit_in_range_p (s, 1, 63));
+ ASSERT_FALSE (bitmap_bit_in_range_p (s, 0, 256));
+
+ bitmap_set_bit (s, 0);
+ bitmap_set_bit (s, 16);
+ bitmap_set_bit (s, 32);
+ bitmap_set_bit (s, 48);
+ bitmap_set_bit (s, 64);
+ ASSERT_TRUE (bitmap_bit_in_range_p (s, 0, 0));
+ ASSERT_TRUE (bitmap_bit_in_range_p (s, 1, 16));
+ ASSERT_TRUE (bitmap_bit_in_range_p (s, 48, 63));
+ ASSERT_TRUE (bitmap_bit_in_range_p (s, 64, 64));
+ ASSERT_FALSE (bitmap_bit_in_range_p (s, 1, 15));
+ ASSERT_FALSE (bitmap_bit_in_range_p (s, 17, 31));
+ ASSERT_FALSE (bitmap_bit_in_range_p (s, 49, 63));
+ ASSERT_FALSE (bitmap_bit_in_range_p (s, 65, 1023));
+}
+
+/* Run all of the selftests within this file. */
+
+void
+sbitmap_c_tests ()
+{
+ test_range_functions ();
+}
+
+} // namespace selftest
+#endif /* CHECKING_P */
diff --git a/gcc/selftest-run-tests.c b/gcc/selftest-run-tests.c
index 30e476d14c5..5c84f3a0737 100644
--- a/gcc/selftest-run-tests.c
+++ b/gcc/selftest-run-tests.c
@@ -56,6 +56,7 @@ selftest::run_tests ()
/* Low-level data structures. */
bitmap_c_tests ();
+ sbitmap_c_tests ();
et_forest_c_tests ();
hash_map_tests_c_tests ();
hash_set_tests_c_tests ();
diff --git a/gcc/selftest.h b/gcc/selftest.h
index 0572fefd281..2e649a70b9e 100644
--- a/gcc/selftest.h
+++ b/gcc/selftest.h
@@ -171,6 +171,7 @@ extern const char *path_to_selftest_files;
/* Declarations for specific families of tests (by source file), in
alphabetical order. */
extern void bitmap_c_tests ();
+extern void sbitmap_c_tests ();
extern void diagnostic_c_tests ();
extern void diagnostic_show_locus_c_tests ();
extern void edit_context_c_tests ();
