re PR tree-optimization/66952 (wrong code at -O2 and -O3 on x86_64-linux-gnu)

2015-07-22  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/66952
	* tree-ssa-ifcombine.c (pass_tree_ifcombine::execute): For
	blocks we end up executing unconditionally reset all SSA
	info such as range and alignment.
	* tree-ssanames.h (reset_flow_sensitive_info): Declare.
	* tree-ssanames.c (reset_flow_sensitive_info): New function.

	* gcc.dg/torture/pr66952.c: New testcase.

From-SVN: r226062

6 files changed, 76 insertions, 1 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 8f2771e..c1838ea 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2015-07-22  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/66952
+	* tree-ssa-ifcombine.c (pass_tree_ifcombine::execute): For
+	blocks we end up executing unconditionally reset all SSA
+	info such as range and alignment.
+	* tree-ssanames.h (reset_flow_sensitive_info): Declare.
+	* tree-ssanames.c (reset_flow_sensitive_info): New function.
+
 2015-07-22  Charles Baylis  <charles.baylis@linaro.org>
 
 	* config/aarch64/aarch64-simd.md (vec_store_lanesoi_lane<mode>): Fix
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 8080308..f4eb4c9 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2015-07-22  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/66952
+	* gcc.dg/torture/pr66952.c: New testcase.
+
 2015-07-22  Charles Baylis  <charles.baylis@linaro.org>
 
         * gcc.target/aarch64/advsimd-intrinsics/vld2_lane_f32_indices_1.c: New
diff --git a/gcc/testsuite/gcc.dg/torture/pr66952.c b/gcc/testsuite/gcc.dg/torture/pr66952.c
new file mode 100644
index 0000000..2a98d2e
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr66952.c
@@ -0,0 +1,28 @@
+/* { dg-do run } */
+
+int a = 128, b;
+
+static int
+fn1 (char p1, int p2)
+{
+  return p1 < 0 || p1 > 1 >> p2 ? 0 : p1 << 1;
+}
+
+static int
+fn2 ()
+{
+  char c = a;
+  b = fn1 (c, 1);
+  if ((128 | c) < 0 ? 1 : 0)
+    return 1;
+  return 0;
+}
+
+int
+main ()
+{
+  if (fn2 () != 1)
+    __builtin_abort ();
+
+  return 0;
+}
diff --git a/gcc/tree-ssa-ifcombine.c b/gcc/tree-ssa-ifcombine.c
index e199689..ef3d16d 100644
--- a/gcc/tree-ssa-ifcombine.c
+++ b/gcc/tree-ssa-ifcombine.c
@@ -765,7 +765,22 @@ pass_tree_ifcombine::execute (function *fun)
 
       if (stmt
 	  && gimple_code (stmt) == GIMPLE_COND)
-	cfg_changed |= tree_ssa_ifcombine_bb (bb);
+	if (tree_ssa_ifcombine_bb (bb))
+	  {
+	    /* Clear range info from all stmts in BB which is now executed
+	       conditional on a always true/false condition.  */
+	    for (gimple_stmt_iterator gsi = gsi_start_bb (bb);
+		 !gsi_end_p (gsi); gsi_next (&gsi))
+	      {
+		gimple stmt = gsi_stmt (gsi);
+		ssa_op_iter i;
+		tree op;
+		FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_DEF)
+		  reset_flow_sensitive_info (op);
+	      }
+
+	    cfg_changed |= true;
+	  }
     }
 
   free (bbs);
diff --git a/gcc/tree-ssanames.c b/gcc/tree-ssanames.c
index 4dd881a..910cb19 100644
--- a/gcc/tree-ssanames.c
+++ b/gcc/tree-ssanames.c
@@ -528,6 +528,23 @@ duplicate_ssa_name_fn (struct function *fn, tree name, gimple stmt)
 }
 
 
+/* Reset all flow sensitive data on NAME such as range-info, nonzero
+   bits and alignment.  */
+
+void
+reset_flow_sensitive_info (tree name)
+{
+  if (POINTER_TYPE_P (TREE_TYPE (name)))
+    {
+      /* points-to info is not flow-sensitive.  */
+      if (SSA_NAME_PTR_INFO (name))
+	mark_ptr_info_alignment_unknown (SSA_NAME_PTR_INFO (name));
+    }
+  else
+    SSA_NAME_RANGE_INFO (name) = NULL;
+}
+
+
 /* Release all the SSA_NAMEs created by STMT.  */
 
 void
diff --git a/gcc/tree-ssanames.h b/gcc/tree-ssanames.h
index a7eeb8f..c6db57e 100644
--- a/gcc/tree-ssanames.h
+++ b/gcc/tree-ssanames.h
@@ -94,6 +94,7 @@ extern void duplicate_ssa_name_ptr_info (tree, struct ptr_info_def *);
 extern tree duplicate_ssa_name_fn (struct function *, tree, gimple);
 extern void duplicate_ssa_name_range_info (tree, enum value_range_type,
 					   struct range_info_def *);
+extern void reset_flow_sensitive_info (tree);
 extern void release_defs (gimple);
 extern void replace_ssa_name_symbol (tree, tree);