diff mbox series

Fix wrong code with pure functions

Message ID 20211112230134.GA97722@kam.mff.cuni.cz
State Committed
Commit 4d2d5565a0953eaa829d10006baf007cf33bab89
Headers
Series Fix wrong code with pure functions |

Commit Message

Jan Hubicka Nov. 12, 2021, 11:01 p.m. UTC 
  Fix wrong code with pure functions

I introduced bug into find_func_aliases_for_call in handling pure functions.
Instead of reading global memory pure functions are believed to write global
memory.  This results in misoptimization of the testcase at -O1.

The change to pta-callused.c updates the template for new behaviour of the
constraint generation. We copy nonlocal memory to calluse which is correct but
also not strictly necessary because later we take care to add nonlocal_p flag
manually.

Bootstrapped/regtested x86_64-linux, comitted.

gcc/ChangeLog:

	PR tree-optimization/103209
	* tree-ssa-structalias.c (find_func_aliases_for_call): Fix
	use of handle_rhs_call

gcc/testsuite/ChangeLog:

	PR tree-optimization/103209
	* gcc.dg/tree-ssa/pta-callused.c: Update template.
	* gcc.c-torture/execute/pr103209.c: New test.
diff mbox series

Patch

diff --git a/gcc/testsuite/gcc.c-torture/execute/pr103209.c b/gcc/testsuite/gcc.c-torture/execute/pr103209.c
new file mode 100644
index 00000000000..481689396f4
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr103209.c
@@ -0,0 +1,36 @@ 
+#include <stdio.h>
+#include <stdint.h>
+
+int32_t a[6];
+int64_t b;
+int32_t *c;
+int32_t **d = &c;
+int64_t *e = &b;
+int32_t **const *f = &d;
+int32_t **const **g = &f;
+int32_t *h();
+static int16_t j();
+static uint32_t k(int8_t, const int32_t *, int64_t);
+static uint32_t l() {
+  int32_t *m = &a[3];
+  int32_t n = 0;
+  int8_t o = 0;
+  int32_t *p[] = {&n, &n, &n, &n};
+  uint32_t q[6][1][2] = {};
+  for (o = 0; o <= 1; o = 6)
+    if (h(j(k(3, 0, q[2][0][0]), &n), n) == p[3])
+      *m = *e;
+  return 0;
+}
+int32_t *h(uint32_t, int32_t) { return ***g; }
+int16_t j(uint32_t, int32_t *r) { **f = r; return 0;}
+uint32_t k(int8_t, const int32_t *, int64_t) { *e = 3; return 0;}
+int main() {
+  int i = 0;
+  l();
+  for (i = 0; i < 6; i++){
+    if (i == 3 && a[i] != 3)
+	__builtin_abort ();
+  }
+  return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pta-callused.c b/gcc/testsuite/gcc.dg/tree-ssa/pta-callused.c
index aa639b45dc2..b9a57d8d135 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/pta-callused.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pta-callused.c
@@ -22,5 +22,5 @@  int bar (int b)
   return *foo (&q);
 }
 
-/* { dg-final { scan-tree-dump "CALLUSED\\(\[0-9\]+\\) = { NONLOCAL f.* i q }" "alias" } } */
+/* { dg-final { scan-tree-dump "CALLUSED\\(\[0-9\]+\\) = { ESCAPED NONLOCAL f.* i q }" "alias" } } */
 
diff --git a/gcc/tree-ssa-structalias.c b/gcc/tree-ssa-structalias.c
index 153ddf57a61..34fd47fdf47 100644
--- a/gcc/tree-ssa-structalias.c
+++ b/gcc/tree-ssa-structalias.c
@@ -4996,7 +4996,7 @@  find_func_aliases_for_call (struct function *fn, gcall *t)
 	 reachable from their arguments, but they are not an escape
 	 point for reachable memory of their arguments.  */
       else if (flags & (ECF_PURE|ECF_LOOPING_CONST_OR_PURE))
-	handle_rhs_call (t, &rhsc, implicit_pure_eaf_flags, true, false);
+	handle_rhs_call (t, &rhsc, implicit_pure_eaf_flags, false, true);
       /* If the call is to a replaceable operator delete and results
 	 from a delete expression as opposed to a direct call to
 	 such operator, then the effects for PTA (in particular