On Thu, 25 Jan 2018, Richard Biener wrote:
--- gcc/match.pd (revision 257047) +++ gcc/match.pd (working copy) @@ -1939,6 +1939,37 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) (minus (convert (view_convert:stype @1)) (convert (view_convert:stype @2)))))))+/* (A * C) +- (B * C) -> (A+-B) * C and (A * C) +- A -> A * (C+-1). + Modeled after fold_plusminus_mult_expr. */ +(if (!TYPE_SATURATING (type) + && (!FLOAT_TYPE_P (type) || flag_associative_math)) + (for plusminus (plus minus) + (simplify + (plusminus (mult:s @0 @1) (mult:cs @0 @2))
No :c on the first mult, so we don't actually handle A*C+B*C? -- Marc Glisse
