procyberian/gcc
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

ipa/105676 - pure attribute suggestion for const function

Browse source 
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.
This commit is contained in:
Richard Biener 2022-12-07 10:26:01 +01:00
parent 3a1a141f79
commit 45e09c2eb9
2 changed files with 17 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

5
gcc/ipa-pure-const.cc
View file

@ -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))

14
gcc/testsuite/gcc.dg/pr105676.c Normal file
View file

@ -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;
}