gimple-ssa-strength-reduction.c (legal_cast_p_1): Forward declaration.

gcc/

	* gimple-ssa-strength-reduction.c (legal_cast_p_1): Forward
	declaration.
	(backtrace_base_for_ref): Call get_unwidened with 'base_in' if
	'base_in' represent a conversion and legal_cast_p_1 holds; set
	'base_in' with the returned value from get_unwidened.

gcc/testsuite/

	* gcc.dg/tree-ssa/slsr-40.c: New test.

From-SVN: r203107

4 files changed, 49 insertions, 0 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 7dc504b..76d188f 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2013-10-02  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
+	    Yufeng Zhang  <yufeng.zhang@arm.com>
+
+	* gimple-ssa-strength-reduction.c (legal_cast_p_1): Forward
+	declaration.
+	(backtrace_base_for_ref): Call get_unwidened with 'base_in' if
+	'base_in' represent a conversion and legal_cast_p_1 holds; set
+	'base_in' with the returned value from get_unwidened.
+
 2013-10-02  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
 
 	* config/arm/arm.c (arm_legitimize_reload_address): Explain why
diff --git a/gcc/gimple-ssa-strength-reduction.c b/gcc/gimple-ssa-strength-reduction.c
index 139a4a1..9a5072c 100644
--- a/gcc/gimple-ssa-strength-reduction.c
+++ b/gcc/gimple-ssa-strength-reduction.c
@@ -379,6 +379,7 @@ static bool address_arithmetic_p;
 /* Forward function declarations.  */
 static slsr_cand_t base_cand_from_table (tree);
 static tree introduce_cast_before_cand (slsr_cand_t, tree, tree);
+static bool legal_cast_p_1 (tree, tree);
 
 /* Produce a pointer to the IDX'th candidate in the candidate vector.  */
 
@@ -768,6 +769,14 @@ backtrace_base_for_ref (tree *pbase)
   slsr_cand_t base_cand;
 
   STRIP_NOPS (base_in);
+
+  /* Strip off widening conversion(s) to handle cases where
+     e.g. 'B' is widened from an 'int' in order to calculate
+     a 64-bit address.  */
+  if (CONVERT_EXPR_P (base_in)
+      && legal_cast_p_1 (base_in, TREE_OPERAND (base_in, 0)))
+    base_in = get_unwidened (base_in, NULL_TREE);
+
   if (TREE_CODE (base_in) != SSA_NAME)
     return tree_to_double_int (integer_zero_node);
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index cb2f58c..2fb3cc6 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2013-10-02  Yufeng Zhang  <yufeng.zhang@arm.com>
+
+	* gcc.dg/tree-ssa/slsr-40.c: New test.
+
 2013-10-01  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/58563
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/slsr-40.c b/gcc/testsuite/gcc.dg/tree-ssa/slsr-40.c
new file mode 100644
index 0000000..72726a3
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/slsr-40.c
@@ -0,0 +1,27 @@
+/* Verify straight-line strength reduction for array
+   subscripting.
+
+   elems[n-1] is reduced to elems + n * 4 + 0xffffffff * 4, only when
+   pointers are of the same size as that of int (assuming 4 bytes).  */
+
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+struct data
+{
+  unsigned long elms[1];
+} gData;
+
+void __attribute__((noinline))
+foo (struct data *dst, unsigned int n)
+{
+  dst->elms[n - 1] &= 1;
+}
+
+int
+main ()
+{
+  foo (&gData, 1);
+  return 0;
+}
+