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diff -urN a/gcc/tree-ssa-math-opts.c b/gcc/tree-ssa-math-opts.c
--- a/gcc/tree-ssa-math-opts.c 2012-12-12 18:05:23.000000000 +0100
+++ b/gcc/tree-ssa-math-opts.c 2013-04-29 15:54:00.051998936 +0200
@@ -1280,6 +1280,47 @@
return result;
}
+/* Return true if stmt is a type conversion operation that can be stripped
+ when used in a widening multiply operation. */
+static bool
+widening_mult_conversion_strippable_p (tree result_type, gimple stmt)
+{
+ enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
+
+ if (TREE_CODE (result_type) == INTEGER_TYPE)
+ {
+ tree op_type;
+ tree inner_op_type;
+
+ if (!CONVERT_EXPR_CODE_P (rhs_code))
+ return false;
+
+ op_type = TREE_TYPE (gimple_assign_lhs (stmt));
+
+ /* If the type of OP has the same precision as the result, then
+ we can strip this conversion. The multiply operation will be
+ selected to create the correct extension as a by-product. */
+ if (TYPE_PRECISION (result_type) == TYPE_PRECISION (op_type))
+ return true;
+
+ /* We can also strip a conversion if it preserves the signed-ness of
+ the operation and doesn't narrow the range. */
+ inner_op_type = TREE_TYPE (gimple_assign_rhs1 (stmt));
+
+ /* If the inner-most type is unsigned, then we can strip any
+ intermediate widening operation. If it's signed, then the
+ intermediate widening operation must also be signed. */
+ if ((TYPE_UNSIGNED (inner_op_type)
+ || TYPE_UNSIGNED (op_type) == TYPE_UNSIGNED (inner_op_type))
+ && TYPE_PRECISION (op_type) > TYPE_PRECISION (inner_op_type))
+ return true;
+
+ return false;
+ }
+
+ return rhs_code == FIXED_CONVERT_EXPR;
+}
+
/* Return true if RHS is a suitable operand for a widening multiplication,
assuming a target type of TYPE.
There are two cases:
@@ -1296,17 +1337,13 @@
{
gimple stmt;
tree type1, rhs1;
- enum tree_code rhs_code;
if (TREE_CODE (rhs) == SSA_NAME)
{
stmt = SSA_NAME_DEF_STMT (rhs);
if (is_gimple_assign (stmt))
{
- rhs_code = gimple_assign_rhs_code (stmt);
- if (TREE_CODE (type) == INTEGER_TYPE
- ? !CONVERT_EXPR_CODE_P (rhs_code)
- : rhs_code != FIXED_CONVERT_EXPR)
+ if (! widening_mult_conversion_strippable_p (type, stmt))
rhs1 = rhs;
else
{
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