OpenE2K
/
gcc
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

re PR rtl-optimization/79910 (wrong code with -O -fweb) 

PR rtl-optimization/79910
	* combine.c (record_used_regs): New static function.
	(try_combine): Handle situations where there is an additional
	instruction between I2 and I3 which needs to have a LOG_LINK
	updated.

	PR rtl-optimization/79910
	* gcc.dg/torture/pr79910.c: New test.

From-SVN: r246226
This commit is contained in:
Bernd Schmidt 2017-03-17 09:10:13 -06:00 committed by Jeff Law
parent 7f166d9447
commit 4a17943d36
4 changed files with 180 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
gcc/ChangeLog
View File

@ -1,3 +1,11 @@
2017-03-17 Bernd Schmidt <bschmidt@redhat.com>
PR rtl-optimization/79910
* combine.c (record_used_regs): New static function.
(try_combine): Handle situations where there is an additional
instruction between I2 and I3 which needs to have a LOG_LINK
updated.
2017-03-17 Jeff Law <law@redhat.com>
PR tree-optimization/71437

138
gcc/combine.c
View File

@ -2559,6 +2559,57 @@ can_split_parallel_of_n_reg_sets (rtx_insn *insn, int n)
return true;
}
/* Set up a set of registers used in an insn. Called through note_uses,
arguments as described for that function. */
static void
record_used_regs (rtx *xptr, void *data)
{
bitmap set = (bitmap)data;
int i, j;
enum rtx_code code;
const char *fmt;
rtx x = *xptr;
/* repeat is used to turn tail-recursion into iteration since GCC
can't do it when there's no return value. */
repeat:
if (x == 0)
return;
code = GET_CODE (x);
if (REG_P (x))
{
unsigned regno = REGNO (x);
unsigned end_regno = END_REGNO (x);
while (regno < end_regno)
bitmap_set_bit (set, regno++);
return;
}
/* Recursively scan the operands of this expression. */
for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--)
{
if (fmt[i] == 'e')
{
/* If we are about to do the last recursive call
needed at this level, change it into iteration.
This function is called enough to be worth it. */
if (i == 0)
{
x = XEXP (x, 0);
goto repeat;
}
record_used_regs (&XEXP (x, i), data);
}
else if (fmt[i] == 'E')
for (j = 0; j < XVECLEN (x, i); j++)
record_used_regs (&XVECEXP (x, i, j), data);
}
}
/* Try to combine the insns I0, I1 and I2 into I3.
Here I0, I1 and I2 appear earlier than I3.
I0 and I1 can be zero; then we combine just I2 into I3, or I1 and I2 into
@ -2742,6 +2793,27 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0,
added_links_insn = 0;
/* For combinations that may result in two insns, we have to gather
some extra information about registers used, so that we can
update all relevant LOG_LINKS later. */
auto_bitmap i2_regset, i3_regset, links_regset;
if (i1)
{
note_uses (&PATTERN (i2), record_used_regs, (bitmap)i2_regset);
note_uses (&PATTERN (i3), record_used_regs, (bitmap)i3_regset);
insn_link *ll;
FOR_EACH_LOG_LINK (ll, i3)
bitmap_set_bit (links_regset, ll->regno);
FOR_EACH_LOG_LINK (ll, i2)
bitmap_set_bit (links_regset, ll->regno);
if (i1)
FOR_EACH_LOG_LINK (ll, i1)
bitmap_set_bit (links_regset, ll->regno);
if (i0)
FOR_EACH_LOG_LINK (ll, i0)
bitmap_set_bit (links_regset, ll->regno);
}
/* First check for one important special case that the code below will
not handle. Namely, the case where I1 is zero, I2 is a PARALLEL
and I3 is a SET whose SET_SRC is a SET_DEST in I2. In that case,
@ -4051,6 +4123,33 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0,
return 0;
}
auto_bitmap new_regs_in_i2;
if (newi2pat)
{
/* We need to discover situations where we introduce a use of a
register into I2, where none of the existing LOG_LINKS contain
a reference to it. This can happen if previously I3 referenced
the reg, and there is an additional use between I2 and I3. We
must remove the LOG_LINKS entry from that additional use and
distribute it along with our own ones. */
note_uses (&newi2pat, record_used_regs, (bitmap)new_regs_in_i2);
bitmap_and_compl_into (new_regs_in_i2, i2_regset);
bitmap_and_compl_into (new_regs_in_i2, links_regset);
/* Here, we first look for situations where a hard register use
moved, and just give up. This should happen approximately
never, and it's not worth it to deal with possibilities like
multi-word registers. Later, when fixing up LOG_LINKS, we
deal with the case where a pseudo use moved. */
if (!bitmap_empty_p (new_regs_in_i2)
&& prev_nonnote_insn (i3) != i2
&& bitmap_first_set_bit (new_regs_in_i2) < FIRST_PSEUDO_REGISTER)
{
undo_all ();
return 0;
}
}
if (MAY_HAVE_DEBUG_INSNS)
{
struct undo *undo;
@ -4493,6 +4592,45 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0,
NULL_RTX, NULL_RTX, NULL_RTX);
}
if (newi2pat)
{
bitmap_iterator iter;
unsigned int i;
/* See comments above where we calculate the bitmap. */
EXECUTE_IF_SET_IN_BITMAP ((bitmap)new_regs_in_i2,
LAST_VIRTUAL_REGISTER, i, iter)
{
rtx reg = regno_reg_rtx[i];
rtx_insn *other;
for (other = NEXT_INSN (i2); other != i3; other = NEXT_INSN (other))
if (NONDEBUG_INSN_P (other)
&& (reg_overlap_mentioned_p (reg, PATTERN (other))
|| (CALL_P (other) && find_reg_fusage (other, USE, reg))))
{
if (dump_file)
fprintf (dump_file,
"found extra use of reg %d at insn %d\n", i,
INSN_UID (other));
insn_link **plink;
for (plink = &LOG_LINKS (other);
*plink;
plink = &(*plink)->next)
{
insn_link *link = *plink;
if (link->regno == i)
{
*plink = link->next;
link->next = i3links;
i3links = link;
break;
}
}
break;
}
}
}
distribute_links (i3links);
distribute_links (i2links);
distribute_links (i1links);

5
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,8 @@
2017-03-17 Bernd Schmidt <bschmidt@redhat.com>
PR rtl-optimization/79910
* gcc.dg/torture/pr79910.c: New test.
2017-03-17 Jeff Law <law@redhat.com>
PR tree-optimization/71437

29
gcc/testsuite/gcc.dg/torture/pr79910.c Normal file
View File

@ -0,0 +1,29 @@
/* { dg-do run } */
/* { dg-additional-options "-fweb" } */
typedef unsigned char u8;
typedef unsigned int u32;
typedef unsigned long long u64;
int a;
static __attribute__ ((noinline, noclone)) u64
foo (u8 p1, u32 p2)
{
u64 b = a <= 0;
p2 = 4;
b >>= a == 0;
p1 %= 0xfffffffff;
p2 >>= b & 31;
p1 += b;
p2 <<= 31;
return p1 + p2 + b;
}
int
main (void)
{
u64 x = foo (0, 1);
if (x != 0)
__builtin_abort ();
return 0;
}