Hi!
As the testcase in the patch shows, if exact memcpy or memset count
is unknown, but max_size is smaller than epilogue_size_needed,
ix86_expand_set_or_movmem can ICE.
The following patch fixes that, bootstrapped/regtested on x86_64-linux
and i686-linux, ok for trunk?
Though, the resulting code doesn't look very good, as everything is expanded
as just epilogue of the copying/memset, I think the probabilities on the
branches expect that all bits of the remaining size are 0 after the main
loop (which isn't done in this case).
2013-11-26 Jakub Jelinek <ja...@redhat.com>
PR target/59229
* config/i386/i386.c (device_alg): Fix up formatting.
(ix86_expand_set_or_movmem): Handle max_size < epilogue_size_needed
similarly to count && count < epilogue_size_needed. Fix up
comment typo.
* builtins.c (determine_block_size): Fix comment typo.
* gcc.c-torture/execute/pr59229.c: New test.
--- gcc/config/i386/i386.c.jj 2013-11-25 18:30:18.000000000 +0100
+++ gcc/config/i386/i386.c 2013-11-26 11:27:38.116198901 +0100
@@ -23453,7 +23453,8 @@ decide_alg (HOST_WIDE_INT count, HOST_WI
/* If expected size is not known but max size is small enough
so inline version is a win, set expected size into
the range. */
- if (max > 1 && (unsigned HOST_WIDE_INT)max >= max_size && expected_size ==
-1)
+ if (max > 1 && (unsigned HOST_WIDE_INT) max >= max_size
+ && expected_size == -1)
expected_size = min_size / 2 + max_size / 2;
/* If user specified the algorithm, honnor it if possible. */
@@ -23752,7 +23753,7 @@ ix86_expand_set_or_movmem (rtx dst, rtx
bool noalign;
enum machine_mode move_mode = VOIDmode;
int unroll_factor = 1;
- /* TODO: Once vlaue ranges are available, fill in proper data. */
+ /* TODO: Once value ranges are available, fill in proper data. */
unsigned HOST_WIDE_INT min_size = 0;
unsigned HOST_WIDE_INT max_size = -1;
unsigned HOST_WIDE_INT probable_max_size = -1;
@@ -23967,21 +23968,19 @@ ix86_expand_set_or_movmem (rtx dst, rtx
loop variant. */
if (issetmem && epilogue_size_needed > 2 && !promoted_val)
force_loopy_epilogue = true;
- if (count)
+ if ((count && count < (unsigned HOST_WIDE_INT) epilogue_size_needed)
+ || max_size < (unsigned HOST_WIDE_INT) epilogue_size_needed)
{
- if (count < (unsigned HOST_WIDE_INT)epilogue_size_needed)
- {
- /* If main algorithm works on QImode, no epilogue is needed.
- For small sizes just don't align anything. */
- if (size_needed == 1)
- desired_align = align;
- else
- goto epilogue;
- }
+ /* If main algorithm works on QImode, no epilogue is needed.
+ For small sizes just don't align anything. */
+ if (size_needed == 1)
+ desired_align = align;
+ else
+ goto epilogue;
}
- else if (min_size < (unsigned HOST_WIDE_INT)epilogue_size_needed)
+ else if (!count
+ && min_size < (unsigned HOST_WIDE_INT) epilogue_size_needed)
{
- gcc_assert (max_size >= (unsigned HOST_WIDE_INT)epilogue_size_needed);
label = gen_label_rtx ();
emit_cmp_and_jump_insns (count_exp,
GEN_INT (epilogue_size_needed),
--- gcc/builtins.c.jj 2013-11-22 21:03:07.000000000 +0100
+++ gcc/builtins.c 2013-11-26 11:15:11.992044093 +0100
@@ -3146,7 +3146,7 @@ determine_block_size (tree len, rtx len_
}
else if (range_type == VR_ANTI_RANGE)
{
- /* Anti range 0...N lets us to determine minmal size to N+1. */
+ /* Anti range 0...N lets us to determine minimal size to N+1. */
if (min.is_zero ())
{
if ((max + double_int_one).fits_uhwi ())
@@ -3156,7 +3156,7 @@ determine_block_size (tree len, rtx len_
int n;
if (n < 100)
- memcpy (a,b, n)
+ memcpy (a, b, n)
Produce anti range allowing negative values of N. We still
can use the information and make a guess that N is not negative.
--- gcc/testsuite/gcc.c-torture/execute/pr59229.c.jj 2013-11-26
11:32:07.590806813 +0100
+++ gcc/testsuite/gcc.c-torture/execute/pr59229.c 2013-11-26
11:31:56.000000000 +0100
@@ -0,0 +1,29 @@
+int i;
+
+__attribute__((noinline, noclone)) void
+bar (char *p)
+{
+ if (i < 1 || i > 6)
+ __builtin_abort ();
+ if (__builtin_memcmp (p, "abcdefg", i + 1) != 0)
+ __builtin_abort ();
+ __builtin_memset (p, ' ', 7);
+}
+
+__attribute__((noinline, noclone)) void
+foo (char *p, unsigned long l)
+{
+ if (l < 1 || l > 6)
+ return;
+ char buf[7];
+ __builtin_memcpy (buf, p, l + 1);
+ bar (buf);
+}
+
+int
+main ()
+{
+ for (i = 0; i < 16; i++)
+ foo ("abcdefghijklmnop", i);
+ return 0;
+}
Jakub
