Hi!
When moving assignment out of a conditional block before the condition, we
need to either reset or update SSA_NAME_RANGE_INFO, otherwise it might be
wrong, because when computed earlier, it could take into account that in
the conditional block the condition is or is not true.
Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk?
2015-02-13 Jakub Jelinek <ja...@redhat.com>
PR tree-optimization/65053
* tree-ssa-phiopt.c (value_replacement): When moving assign before
cond, either reset VR on lhs or set it to phi result VR.
* gcc.c-torture/execute/pr65053-1.c: New test.
* gcc.c-torture/execute/pr65053-2.c: New test.
--- gcc/tree-ssa-phiopt.c.jj 2015-01-15 20:25:39.000000000 +0100
+++ gcc/tree-ssa-phiopt.c 2015-02-13 18:19:39.990627277 +0100
@@ -917,6 +917,31 @@ value_replacement (basic_block cond_bb,
&& absorbing_element_p (code_def, cond_rhs))))
{
gsi = gsi_for_stmt (cond);
+ if (INTEGRAL_TYPE_P (TREE_TYPE (lhs)))
+ {
+ /* Moving ASSIGN might change VR of lhs, e.g. when moving u_6
+ def-stmt in:
+ if (n_5 != 0)
+ goto <bb 3>;
+ else
+ goto <bb 4>;
+
+ <bb 3>:
+ # RANGE [0, 4294967294]
+ u_6 = n_5 + 4294967295;
+
+ <bb 4>:
+ # u_3 = PHI <u_6(3), 4294967295(2)> */
+ SSA_NAME_RANGE_INFO (lhs) = NULL;
+ SSA_NAME_ANTI_RANGE_P (lhs) = 0;
+ /* If available, we can use VR of phi result at least. */
+ tree phires = gimple_phi_result (phi);
+ struct range_info_def *phires_range_info
+ = SSA_NAME_RANGE_INFO (phires);
+ if (phires_range_info)
+ duplicate_ssa_name_range_info (lhs, SSA_NAME_RANGE_TYPE (phires),
+ phires_range_info);
+ }
gimple_stmt_iterator gsi_from = gsi_for_stmt (assign);
gsi_move_before (&gsi_from, &gsi);
replace_phi_edge_with_variable (cond_bb, e1, phi, lhs);
--- gcc/testsuite/gcc.c-torture/execute/pr65053-1.c.jj 2015-02-13
18:45:40.149071898 +0100
+++ gcc/testsuite/gcc.c-torture/execute/pr65053-1.c 2015-02-13
18:40:53.000000000 +0100
@@ -0,0 +1,32 @@
+/* PR tree-optimization/65053 */
+
+int i;
+
+__attribute__ ((noinline, noclone))
+unsigned int foo (void)
+{
+ return 0;
+}
+
+int
+main ()
+{
+ unsigned int u = -1;
+ if (u == -1)
+ {
+ unsigned int n = foo ();
+ if (n > 0)
+ u = n - 1;
+ }
+
+ while (u != -1)
+ {
+ asm ("" : "+g" (u));
+ u = -1;
+ i = 1;
+ }
+
+ if (i)
+ __builtin_abort ();
+ return 0;
+}
--- gcc/testsuite/gcc.c-torture/execute/pr65053-2.c.jj 2015-02-13
18:45:43.552016154 +0100
+++ gcc/testsuite/gcc.c-torture/execute/pr65053-2.c 2015-02-13
18:44:59.000000000 +0100
@@ -0,0 +1,27 @@
+/* PR tree-optimization/65053 */
+
+int i;
+unsigned int x;
+
+int
+main ()
+{
+ asm volatile ("" : "+g" (x));
+ unsigned int n = x;
+ unsigned int u = 32;
+ if (n >= 32)
+ __builtin_abort ();
+ if (n != 0)
+ u = n + 32;
+
+ while (u != 32)
+ {
+ asm ("" : : "g" (u));
+ u = 32;
+ i = 1;
+ }
+
+ if (i)
+ __builtin_abort ();
+ return 0;
+}
Jakub
