On Mon, 26 Jul 2021, Roger Sayle wrote:
The one aspect that's a little odd is that each transform is paired with
a convert@1 variant, using the efficient match machinery to expose any
zero extension to fold-const.c's tree_nonzero_bits functionality.
Copying the first transform for context
+(for op (bit_ior bit_xor)
+ (simplify
+ (op (mult:s@0 @1 INTEGER_CST@2)
+ (mult:s@3 @1 INTEGER_CST@4))
+ (if (INTEGRAL_TYPE_P (type) && TYPE_OVERFLOW_WRAPS (type)
+ && (tree_nonzero_bits (@0) & tree_nonzero_bits (@3)) == 0)
+ (mult @1
+ { wide_int_to_tree (type, wi::to_wide (@2) + wi::to_wide (@4)); })))
+ (simplify
+ (op (mult:s@0 (convert@1 @2) INTEGER_CST@3)
+ (mult:s@4 (convert@1 @2) INTEGER_CST@5))
+ (if (INTEGRAL_TYPE_P (type) && TYPE_OVERFLOW_WRAPS (type)
+ && (tree_nonzero_bits (@0) & tree_nonzero_bits (@4)) == 0)
+ (mult @1
+ { wide_int_to_tree (type, wi::to_wide (@3) + wi::to_wide (@5)); })))
Could you explain how the convert helps exactly?
--
Marc Glisse
