diff options
| author | Richard Biener <rguenther@suse.de> | 2022-12-07 10:26:01 +0100 |
|---|---|---|
| committer | Richard Biener <rguenther@suse.de> | 2022-12-07 11:28:00 +0100 |
| commit | 45e09c2eb9c2bdd34ef777e06ddc9908dd0664f9 (patch) | |
| tree | a6b559ea9c8b4decd2d5c1efbac5b7be49a3ac01 | |
| parent | 3a1a141f79c83ad38f7db3a21d8a4dcfe625c176 (diff) | |
| download | gcc-45e09c2eb9c2bdd34ef777e06ddc9908dd0664f9.zip gcc-45e09c2eb9c2bdd34ef777e06ddc9908dd0664f9.tar.gz gcc-45e09c2eb9c2bdd34ef777e06ddc9908dd0664f9.tar.bz2 | |
ipa/105676 - pure attribute suggestion for const function
When a function is declared const (even though it technically
accesses memory), ipa-modref discovering pureness shouldn't end
up suggesting that attribute. The following thus exempts
'const' functions from ipa_make_function_pure handling.
PR ipa/105676
* ipa-pure-const.cc (ipa_make_function_pure): Skip also
for functions already being const.
* gcc.dg/pr105676.c: New testcase.
| -rw-r--r-- | gcc/ipa-pure-const.cc | 5 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.dg/pr105676.c | 14 |
2 files changed, 17 insertions, 2 deletions
diff --git a/gcc/ipa-pure-const.cc b/gcc/ipa-pure-const.cc index 572a6da..0b748ee 100644 --- a/gcc/ipa-pure-const.cc +++ b/gcc/ipa-pure-const.cc @@ -1526,8 +1526,9 @@ ipa_make_function_pure (struct cgraph_node *node, bool looping, bool local) { bool cdtor = false; - if (DECL_PURE_P (node->decl) - && (looping || !DECL_LOOPING_CONST_OR_PURE_P (node->decl))) + if (TREE_READONLY (node->decl) + || (DECL_PURE_P (node->decl) + && (looping || !DECL_LOOPING_CONST_OR_PURE_P (node->decl)))) return false; warn_function_pure (node->decl, !looping); if (local && skip_function_for_local_pure_const (node)) diff --git a/gcc/testsuite/gcc.dg/pr105676.c b/gcc/testsuite/gcc.dg/pr105676.c new file mode 100644 index 0000000..077fc18 --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr105676.c @@ -0,0 +1,14 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -Wsuggest-attribute=pure" } */ + +__attribute__((const)) +extern int do_expensive_calculation(void); + +__attribute__((const)) +int getval(void) /* { dg-bogus "candidate for attribute" } */ +{ + static int cache = -1; + if (cache == -1) + cache = do_expensive_calculation(); + return cache; +} |