git
/
gcc
mirror of git://gcc.gnu.org/git/gcc.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Fix merging of 2 predictors (PR tree-optimization/86925). 

2018-08-15  Martin Liska  <mliska@suse.cz>

        PR tree-optimization/86925
	* predict.c (expr_expected_value_1): When taking
        later predictor, assign also probability.
        Use fold_build2_initializer_loc in order to fold
        the expression in -frounding-math.
2018-08-15  Martin Liska  <mliska@suse.cz>

        PR tree-optimization/86925
	* gcc.dg/predict-20.c: New test.
	* gcc.dg/predict-21.c: New test.

From-SVN: r263552
This commit is contained in:
Martin Liska 2018-08-15 10:55:15 +02:00 committed by Martin Liska
parent 0806181f23
commit 7c8357def1
5 changed files with 58 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
gcc/ChangeLog
View File

@ -1,3 +1,11 @@
2018-08-15 Martin Liska <mliska@suse.cz>
PR tree-optimization/86925
* predict.c (expr_expected_value_1): When taking
later predictor, assign also probability.
Use fold_build2_initializer_loc in order to fold
the expression in -frounding-math.
2018-08-14 Allan Sandfeld Jensen <allan.jensen@qt.io> 2018-08-14 Allan Sandfeld Jensen <allan.jensen@qt.io>
* config/i386/i386.c (expand_vec_perm_movs): New method matching movs * config/i386/i386.c (expand_vec_perm_movs): New method matching movs

11
gcc/predict.c
View File

@ -2332,13 +2332,17 @@ expr_expected_value_1 (tree type, tree op0, enum tree_code code,
if (arg == PHI_RESULT (def)) if (arg == PHI_RESULT (def))
continue; continue;
HOST_WIDE_INT probability2;
new_val = expr_expected_value (arg, visited, &predictor2, new_val = expr_expected_value (arg, visited, &predictor2,
probability); &probability2);
/* It is difficult to combine value predictors. Simply assume /* It is difficult to combine value predictors. Simply assume
that later predictor is weaker and take its prediction. */ that later predictor is weaker and take its prediction. */
if (*predictor < predictor2) if (*predictor < predictor2)
*predictor = predictor2; {
*predictor = predictor2;
*probability = probability2;
}
if (!new_val) if (!new_val)
return NULL; return NULL;
if (!val) if (!val)
@ -2423,7 +2427,8 @@ expr_expected_value_1 (tree type, tree op0, enum tree_code code,
tree base = build_int_cst (integer_type_node, tree base = build_int_cst (integer_type_node,
REG_BR_PROB_BASE); REG_BR_PROB_BASE);
base = build_real_from_int_cst (t, base); base = build_real_from_int_cst (t, base);
tree r = fold_build2 (MULT_EXPR, t, prob, base); tree r = fold_build2_initializer_loc (UNKNOWN_LOCATION,
MULT_EXPR, t, prob, base);
HOST_WIDE_INT probi HOST_WIDE_INT probi
= real_to_integer (TREE_REAL_CST_PTR (r)); = real_to_integer (TREE_REAL_CST_PTR (r));
if (probi >= 0 && probi <= REG_BR_PROB_BASE) if (probi >= 0 && probi <= REG_BR_PROB_BASE)

6
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,9 @@
2018-08-15 Martin Liska <mliska@suse.cz>
PR tree-optimization/86925
* gcc.dg/predict-20.c: New test.
* gcc.dg/predict-21.c: New test.
2018-08-15 Paolo Carlini <paolo.carlini@oracle.com> 2018-08-15 Paolo Carlini <paolo.carlini@oracle.com>
* g++.dg/init/goto3.C: Adjust for error instead of permerror. * g++.dg/init/goto3.C: Adjust for error instead of permerror.

23
gcc/testsuite/gcc.dg/predict-20.c Normal file
View File

@ -0,0 +1,23 @@
/* PR tree-optimization/86925 */
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-profile_estimate" } */
int a, b;
void
c ()
{
for (;;)
{
if (__builtin_expect (b < 0, 0))
break;
if (__builtin_expect (a, 1))
break;
}
int d = b < 0;
if (__builtin_expect (d, 0))
asm("");
}
/* { dg-final { scan-tree-dump-times "__builtin_expect heuristics of edge" 3 "profile_estimate"} } */

13
gcc/testsuite/gcc.dg/predict-21.c Normal file
View File

@ -0,0 +1,13 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-profile_estimate -frounding-math" } */
extern int global;
void foo (int base)
{
for (int i = 0; __builtin_expect_with_probability (i < base, 1, 0.05f); i++)
global++;
}
/* { dg-final { scan-tree-dump "first match heuristics: 5.00%" "profile_estimate"} } */
/* { dg-final { scan-tree-dump "__builtin_expect_with_probability heuristics of edge .*->.*: 5.00%" "profile_estimate"} } */