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re PR target/59625 (asm goto and TARGET_FOUR_JUMP_LIMIT)

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PR target/59625
	* config/i386/i386.c (ix86_avoid_jump_mispredicts): Don't consider
	asm goto as jump.

	* gcc.target/i386/pr59625.c: New test.

From-SVN: r206314
This commit is contained in:
Jakub Jelinek 2014-01-03 13:22:17 +01:00 committed by Jakub Jelinek
parent cdc23b1b20
commit 3bcdbd50ba
4 changed files with 55 additions and 4 deletions
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4
gcc/ChangeLog
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@ -1,5 +1,9 @@
2014-01-03 Jakub Jelinek <jakub@redhat.com>
PR target/59625
* config/i386/i386.c (ix86_avoid_jump_mispredicts): Don't consider
asm goto as jump.
* config/i386/i386.md (MODE_SIZE): New mode attribute.
(push splitter): Use <P:MODE_SIZE> instead of
GET_MODE_SIZE (<P:MODE>mode).

14
gcc/config/i386/i386.c
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@ -38825,7 +38825,10 @@ ix86_avoid_jump_mispredicts (void)
The smallest offset in the page INSN can start is the case where START
ends on the offset 0. Offset of INSN is then NBYTES - sizeof (INSN).
We add p2align to 16byte window with maxskip 15 - NBYTES + sizeof (INSN).
*/
Don't consider asm goto as jump, while it can contain a jump, it doesn't
have to, control transfer to label(s) can be performed through other
means, and also we estimate minimum length of all asm stmts as 0. */
for (insn = start; insn; insn = NEXT_INSN (insn))
{
int min_size;
@ -38852,7 +38855,8 @@ ix86_avoid_jump_mispredicts (void)
while (nbytes + max_skip >= 16)
{
start = NEXT_INSN (start);
if (JUMP_P (start) || CALL_P (start))
if ((JUMP_P (start) && asm_noperands (PATTERN (start)) < 0)
|| CALL_P (start))
njumps--, isjump = 1;
else
isjump = 0;
@ -38867,7 +38871,8 @@ ix86_avoid_jump_mispredicts (void)
if (dump_file)
fprintf (dump_file, "Insn %i estimated to %i bytes\n",
INSN_UID (insn), min_size);
if (JUMP_P (insn) || CALL_P (insn))
if ((JUMP_P (insn) && asm_noperands (PATTERN (insn)) < 0)
|| CALL_P (insn))
njumps++;
else
continue;
@ -38875,7 +38880,8 @@ ix86_avoid_jump_mispredicts (void)
while (njumps > 3)
{
start = NEXT_INSN (start);
if (JUMP_P (start) || CALL_P (start))
if ((JUMP_P (start) && asm_noperands (PATTERN (start)) < 0)
|| CALL_P (start))
njumps--, isjump = 1;
else
isjump = 0;

5
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,8 @@
2014-01-03 Jakub Jelinek <jakub@redhat.com>
PR target/59625
* gcc.target/i386/pr59625.c: New test.
2014-01-03 Paolo Carlini <paolo.carlini@oracle.com>
Core DR 1442

36
gcc/testsuite/gcc.target/i386/pr59625.c Normal file
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@ -0,0 +1,36 @@
/* PR target/59625 */
/* { dg-do compile } */
/* { dg-options "-O2 -mtune=atom" } */
int
foo (void)
{
asm goto ("" : : : : lab);
asm goto ("" : : : : lab);
asm goto ("" : : : : lab);
asm goto ("" : : : : lab);
asm goto ("" : : : : lab);
asm goto ("" : : : : lab);
asm goto ("" : : : : lab);
asm goto ("" : : : : lab);
asm goto ("" : : : : lab);
asm goto ("" : : : : lab);
asm goto ("" : : : : lab);
asm goto ("" : : : : lab);
asm goto ("" : : : : lab);
asm goto ("" : : : : lab);
asm goto ("" : : : : lab);
asm goto ("" : : : : lab);
asm goto ("" : : : : lab);
asm goto ("" : : : : lab);
asm goto ("" : : : : lab);
asm goto ("" : : : : lab);
return 0;
lab:
return 1;
}
/* Verify we don't consider asm goto as a jump for four jumps limit
optimization. asm goto doesn't have to contain a jump at all,
the branching to labels can happen through different means. */
/* { dg-final { scan-assembler-not "(p2align\[^\n\r\]*\[\n\r]*\[^\n\r\]*){8}p2align" } } */