From ba2aa6cb7367f529ad96ece92e25cd0366a28735 Mon Sep 17 00:00:00 2001 From: marxin Date: Thu, 26 Jul 2018 15:25:00 +0200 Subject: [PATCH] Add malloc predictor (PR middle-end/83023). gcc/ChangeLog: 2018-07-26 Martin Liska PR middle-end/83023 * predict.c (expr_expected_value_1): Handle DECL_IS_MALLOC declarations. * predict.def (PRED_MALLOC_NONNULL): New predictor. gcc/testsuite/ChangeLog: 2018-07-26 Martin Liska PR middle-end/83023 * gcc.dg/predict-16.c: New test. --- gcc/predict.c | 8 ++++++++ gcc/predict.def | 5 ++++- gcc/testsuite/gcc.dg/predict-16.c | 31 +++++++++++++++++++++++++++++++ 3 files changed, 43 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/gcc.dg/predict-16.c diff --git a/gcc/predict.c b/gcc/predict.c index a6769eda1c7..a7b2223c697 100644 --- a/gcc/predict.c +++ b/gcc/predict.c @@ -2380,6 +2380,14 @@ expr_expected_value_1 (tree type, tree op0, enum tree_code code, } return NULL; } + + if (DECL_IS_MALLOC (decl)) + { + if (predictor) + *predictor = PRED_MALLOC_NONNULL; + return boolean_true_node; + } + if (DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL) switch (DECL_FUNCTION_CODE (decl)) { diff --git a/gcc/predict.def b/gcc/predict.def index 4ed97ed165c..426c17f26fd 100644 --- a/gcc/predict.def +++ b/gcc/predict.def @@ -88,6 +88,10 @@ DEF_PREDICTOR (PRED_NORETURN, "noreturn call", PROB_VERY_LIKELY, DEF_PREDICTOR (PRED_COLD_FUNCTION, "cold function call", PROB_VERY_LIKELY, PRED_FLAG_FIRST_MATCH) +/* Return value of malloc function is almost always non-null. */ +DEF_PREDICTOR (PRED_MALLOC_NONNULL, "malloc returned non-NULL", \ + PROB_VERY_LIKELY, PRED_FLAG_FIRST_MATCH) + /* Edge causing loop to terminate is probably not taken. */ DEF_PREDICTOR (PRED_LOOP_EXIT, "loop exit", HITRATE (89), PRED_FLAG_FIRST_MATCH) @@ -169,7 +173,6 @@ DEF_PREDICTOR (PRED_HOT_LABEL, "hot label", HITRATE (85), 0) DEF_PREDICTOR (PRED_COLD_LABEL, "cold label", PROB_VERY_LIKELY, PRED_FLAG_FIRST_MATCH) - /* The following predictors are used in Fortran. */ /* Branch leading to an integer overflow are extremely unlikely. */ diff --git a/gcc/testsuite/gcc.dg/predict-16.c b/gcc/testsuite/gcc.dg/predict-16.c new file mode 100644 index 00000000000..3a3e943bb79 --- /dev/null +++ b/gcc/testsuite/gcc.dg/predict-16.c @@ -0,0 +1,31 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fdump-tree-profile_estimate" } */ + +#include +#include + +void *r; +void *r2; +void *r3; +void *r4; + +void *m (size_t s, int c) +{ + r = malloc (s); + if (r) + memset (r, 0, s); + + r2 = calloc (s, 0); + if (r2) + memset (r2, 0, s); + + r3 = __builtin_malloc (s); + if (r3) + memset (r3, 0, s); + + r4 = __builtin_calloc (s, 0); + if (r4) + memset (r4, 0, s); +} + +/* { dg-final { scan-tree-dump-times "malloc returned non-NULL heuristics of edge\[^:\]*: 99.96%" 4 "profile_estimate"} } */ -- 2.18.0