Hi!
single_imm_use (to my surprise) modifies what it's last argument points to
even when returning false, this function wasn't expecting that.
Furthermore, if a the var is used in a store which does't have lhs as
SSA_NAME, this would ICE.
Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux,
committed to trunk as obvious.
2013-11-04 Jakub Jelinek <ja...@redhat.com>
PR tree-optimization/58978
* tree-vrp.c (all_imm_uses_in_stmt_or_feed_cond): Don't modify
use_stmt by single_imm_use directly. Only call single_imm_use
on SSA_NAMEs.
* gcc.c-torture/compile/pr58978.c: New test.
--- gcc/tree-vrp.c.jj 2013-11-04 11:27:35.694278458 +0100
+++ gcc/tree-vrp.c 2013-11-04 16:16:59.607689824 +0100
@@ -6472,13 +6472,14 @@ all_imm_uses_in_stmt_or_feed_cond (tree
FOR_EACH_IMM_USE_FAST (use_p, iter, var)
if (USE_STMT (use_p) != stmt)
{
- gimple use_stmt = USE_STMT (use_p);
+ gimple use_stmt = USE_STMT (use_p), use_stmt2;
if (is_gimple_debug (use_stmt))
continue;
while (is_gimple_assign (use_stmt)
+ && TREE_CODE (gimple_assign_lhs (use_stmt)) == SSA_NAME
&& single_imm_use (gimple_assign_lhs (use_stmt),
- &use2_p, &use_stmt))
- ;
+ &use2_p, &use_stmt2))
+ use_stmt = use_stmt2;
if (gimple_code (use_stmt) != GIMPLE_COND
|| gimple_bb (use_stmt) != cond_bb)
return false;
--- gcc/testsuite/gcc.c-torture/compile/pr58978.c.jj 2013-11-04
16:16:18.542905275 +0100
+++ gcc/testsuite/gcc.c-torture/compile/pr58978.c 2013-11-04
16:16:18.542905275 +0100
@@ -0,0 +1,16 @@
+/* PR tree-optimization/58978 */
+
+int
+foo (int x)
+{
+ switch (x)
+ {
+ case 0:
+ case 1:
+ case 9:
+ break;
+ default:
+ __builtin_unreachable ();
+ }
+ return x;
+}
Jakub
