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

gimple: Ignore *0 = {CLOBBER} in path isolation [PR96722]

Browse source 
Clobbers of MEM_REF with NULL address are just fancy nops, something we just
ignore and don't emit any code for it (ditto for other clobbers), they just
mark end of life on something, so we shouldn't infer from those that there
is some UB.

2020-08-25  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/96722
	* gimple.c (infer_nonnull_range): Formatting fix.
	(infer_nonnull_range_by_dereference): Return false for clobber stmts.

	* g++.dg/opt/pr96722.C: New test.
This commit is contained in:
Jakub Jelinek 2020-08-25 13:49:40 +02:00
parent f982a6ec9b
commit a5b15fcb95
2 changed files with 24 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

7
gcc/gimple.c
View file

@ -2917,8 +2917,8 @@ check_loadstore (gimple *, tree op, tree, void *data)
bool
infer_nonnull_range (gimple *stmt, tree op)
{
return infer_nonnull_range_by_dereference (stmt, op)
|| infer_nonnull_range_by_attribute (stmt, op);
return (infer_nonnull_range_by_dereference (stmt, op)
|| infer_nonnull_range_by_attribute (stmt, op));
}
/* Return true if OP can be inferred to be non-NULL after STMT
@ -2930,7 +2930,8 @@ infer_nonnull_range_by_dereference (gimple *stmt, tree op)
non-NULL if -fdelete-null-pointer-checks is enabled. */
if (!flag_delete_null_pointer_checks
|| !POINTER_TYPE_P (TREE_TYPE (op))
|| gimple_code (stmt) == GIMPLE_ASM)
|| gimple_code (stmt) == GIMPLE_ASM
|| gimple_clobber_p (stmt))
return false;
if (walk_stmt_load_store_ops (stmt, (void *)op,

20
gcc/testsuite/g++.dg/opt/pr96722.C Normal file
View file

@ -0,0 +1,20 @@
// PR tree-optimization/96722
// { dg-do run }
// { dg-options "-O2" }
struct S { int s; ~S () {} };
void
foo (S *a)
{
if (a)
return;
a->~S ();
}
int
main ()
{
S s;
foo (&s);
}