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73b7c776e9
Fix "Widening multiply-accumulate operation uses wrong value extension" for 4.7, 4.7-linaro and 4.6-linaro, which backported the broken code to 4.6. Vanilla 4.6 is unaffected. Fixes #13420. Signed-off-by: Jonas Gorski <jogo@openwrt.org> SVN-Revision: 36486
71 lines
2.2 KiB
Diff
71 lines
2.2 KiB
Diff
diff -urN a/gcc/tree-ssa-math-opts.c b/gcc/tree-ssa-math-opts.c
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--- a/gcc/tree-ssa-math-opts.c 2012-12-12 18:05:23.000000000 +0100
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+++ b/gcc/tree-ssa-math-opts.c 2013-04-29 15:54:00.051998936 +0200
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@@ -1280,6 +1280,47 @@
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return result;
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}
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+/* Return true if stmt is a type conversion operation that can be stripped
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+ when used in a widening multiply operation. */
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+static bool
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+widening_mult_conversion_strippable_p (tree result_type, gimple stmt)
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+{
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+ enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
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+
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+ if (TREE_CODE (result_type) == INTEGER_TYPE)
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+ {
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+ tree op_type;
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+ tree inner_op_type;
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+
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+ if (!CONVERT_EXPR_CODE_P (rhs_code))
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+ return false;
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+
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+ op_type = TREE_TYPE (gimple_assign_lhs (stmt));
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+
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+ /* If the type of OP has the same precision as the result, then
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+ we can strip this conversion. The multiply operation will be
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+ selected to create the correct extension as a by-product. */
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+ if (TYPE_PRECISION (result_type) == TYPE_PRECISION (op_type))
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+ return true;
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+
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+ /* We can also strip a conversion if it preserves the signed-ness of
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+ the operation and doesn't narrow the range. */
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+ inner_op_type = TREE_TYPE (gimple_assign_rhs1 (stmt));
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+
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+ /* If the inner-most type is unsigned, then we can strip any
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+ intermediate widening operation. If it's signed, then the
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+ intermediate widening operation must also be signed. */
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+ if ((TYPE_UNSIGNED (inner_op_type)
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+ || TYPE_UNSIGNED (op_type) == TYPE_UNSIGNED (inner_op_type))
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+ && TYPE_PRECISION (op_type) > TYPE_PRECISION (inner_op_type))
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+ return true;
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+
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+ return false;
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+ }
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+
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+ return rhs_code == FIXED_CONVERT_EXPR;
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+}
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+
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/* Return true if RHS is a suitable operand for a widening multiplication,
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assuming a target type of TYPE.
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There are two cases:
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@@ -1296,17 +1337,13 @@
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{
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gimple stmt;
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tree type1, rhs1;
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- enum tree_code rhs_code;
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if (TREE_CODE (rhs) == SSA_NAME)
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{
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stmt = SSA_NAME_DEF_STMT (rhs);
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if (is_gimple_assign (stmt))
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{
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- rhs_code = gimple_assign_rhs_code (stmt);
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- if (TREE_CODE (type) == INTEGER_TYPE
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- ? !CONVERT_EXPR_CODE_P (rhs_code)
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- : rhs_code != FIXED_CONVERT_EXPR)
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+ if (! widening_mult_conversion_strippable_p (type, stmt))
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rhs1 = rhs;
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else
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{
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