https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114511
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> --- Confirmed. _3 = _1 + _2; y = _3; _18 = b_9(D) + c_12(D); _19 = _18 - a_8(D); _20 = _3 + _19; _6 = _20 - _1; re-association doesn't associate the def of _3 because it has multiple uses and there's no special handling of ((_1 + _2) + _19) - _1 what makes this work for -fno-wrapv is the fre1 difference (+ is -fwrapv) Replaced y with _3 in all uses of y.0_4 = y; +Matching expression match.pd:2030, gimple-match-6.cc:54 +Applying pattern match.pd:2057, gimple-match-2.cc:4362 +Applying pattern match.pd:2048, gimple-match-6.cc:2758 +gimple_simplified to _18 = b_12(D) - a_11(D); +_5 = _18 - _1; Replaced x with _5 in all uses of x.1_6 = x; -Applying pattern match.pd:4682, gimple-match-6.cc:4679 -Applying pattern match.pd:3432, gimple-match-7.cc:531 -gimple_simplified to _18 = c_16(D) - _3; -_7 = _18; Replaced y with _3 in all uses of y.2_8 = y; -Applying pattern match.pd:4682, gimple-match-7.cc:4394 -Applying pattern match.pd:3494, gimple-match-6.cc:508 -gimple_simplified to _9 = c_16(D); Removing dead stmt y.2_8 = y; Removing dead stmt x.1_6 = x; Removing dead stmt y.0_4 = y; @@ -77,12 +77,12 @@ _2 = a_11(D) - b_12(D); _3 = _1 + _2; y = _3; - _5 = -_3; + _18 = b_12(D) - a_11(D); + _5 = _18 - _1; x = _5; - _18 = c_16(D) - _3; - _7 = _18; - _9 = c_16(D); - x = c_16(D); + _7 = _5 + c_16(D); + _9 = _3 + _7; + x = _9; return; }
