Hi!
The following testcase FAILs, because we don't mark the child OpenMP function
as cfun->calls_alloca when it does call alloca. When optimizing, during DCE we
reset those flags and recompute them again, but with -O0 DCE is not performed.
Fixed by calling notice_special_calls when moving insns to the child function.
cfun->calls_alloca is normally set during gimplification and most of the
alloca calls omp-low.c does go through the gimplifier, but one spot didn't
and built the gcall directly, so that one needs to set calls_alloca too.
Bootstrapped/regtested on x86_64-linux and i686-linux, committed to trunk.
2020-10-08 Jakub Jelinek <ja...@redhat.com>
PR sanitizer/97294
* tree-cfg.c (move_block_to_fn): Call notice_special_calls on
call stmts being moved into dest_cfun.
* omp-low.c (lower_rec_input_clauses): Set cfun->calls_alloca when
adding __builtin_alloca_with_align call without gimplification.
* gcc.dg/asan/pr97294.c: New test.
--- gcc/tree-cfg.c.jj 2020-09-02 12:13:22.617071099 +0200
+++ gcc/tree-cfg.c 2020-10-07 17:36:13.138847818 +0200
@@ -7220,6 +7220,8 @@ move_block_to_fn (struct function *dest_
free_stmt_operands (cfun, stmt);
push_cfun (dest_cfun);
update_stmt (stmt);
+ if (is_gimple_call (stmt))
+ notice_special_calls (as_a <gcall *> (stmt));
pop_cfun ();
}
--- gcc/omp-low.c.jj 2020-09-29 13:35:18.230153537 +0200
+++ gcc/omp-low.c 2020-10-07 16:27:31.582642216 +0200
@@ -5112,6 +5112,7 @@ lower_rec_input_clauses (tree clauses, g
atmp = builtin_decl_explicit (BUILT_IN_ALLOCA_WITH_ALIGN);
stmt = gimple_build_call (atmp, 2, x,
size_int (DECL_ALIGN (var)));
+ cfun->calls_alloca = 1;
tmp = create_tmp_var_raw (ptr_type_node);
gimple_add_tmp_var (tmp);
gimple_call_set_lhs (stmt, tmp);
--- gcc/testsuite/gcc.dg/asan/pr97294.c.jj 2020-10-07 19:52:24.945460248
+0200
+++ gcc/testsuite/gcc.dg/asan/pr97294.c 2020-10-07 19:56:37.662856063 +0200
@@ -0,0 +1,41 @@
+/* PR sanitizer/97294 */
+/* { dg-do compile { target fopenmp } } */
+/* { dg-skip-if "" { *-*-* } { "*" } { "-O0" } } */
+/* { dg-options "-O0 -fsanitize=address -fopenmp" } */
+/* { dg-final { scan-assembler "foo._omp_fn.\[0-9]\[1-9]*:.*call\[
\t]\*__*asan_allocas_unpoison.*\.size\[ \t]\*foo._omp_fn.\[0-9]\[1-9]*," {
target x86_64-*-linux* i?86-*-linux* } } } */
+
+__attribute__((noipa)) void
+foo (int *p, int n)
+{
+ int i;
+ #pragma omp parallel for num_threads(2) reduction(+:p[:n])
+ for (i = 0; i < 10; i++)
+ {
+ p[0]++;
+ p[n - 1] += 2;
+ }
+}
+
+__attribute__((noipa)) void
+bar (void)
+{
+ unsigned char buf[1024];
+ int i;
+ asm volatile ("" : : "r" (&buf[0]) : "memory");
+ for (i = 0; i < 1024; i++)
+ buf[i] = i;
+ asm volatile ("" : : "r" (&buf[0]) : "memory");
+}
+
+int
+main ()
+{
+ int p[50], i;
+ for (i = 0; i < 50; i++)
+ p[i] = 0;
+ foo (p, 50);
+ bar ();
+ if (p[0] != 10 || p[49] != 20)
+ __builtin_abort ();
+ return 0;
+}
Jakub
