https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91166
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |missed-optimization
Status|UNCONFIRMED |NEW
Last reconfirmed| |2019-07-15
Component|tree-optimization |middle-end
Version|unknown |10.0
Ever confirmed|0 |1
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
_4 = VEC_PERM_EXPR <{ 0, ... }, { 0, ... }, { 0, POLY_INT_CST [2, 2], 1,
POLY_INT_CST [3, 2], 2, POLY_INT_CST [4, 2], ... }>;
_35 = VEC_PERM_EXPR <_4, _4, { 0, 0, 1, 1, 2, 2, ... }>;
_14 = VEC_PERM_EXPR <_4, _4, { POLY_INT_CST [1, 1], POLY_INT_CST [1, 1],
POLY_INT_CST [2, 1], POLY_INT_CST [2, 1], POLY_INT_CST [3, 1], POLY_INT_CST [3,
1], ... }>;
I guess? Note the vectorizer shouldn't generate unfolded permutes. Note
even forwprop doesn't do anything to the above.
I somehow expected that two the permute with two uniform same vectors
would be constant folded indeed, but somehow
_4 = VEC_PERM_EXPR <{ 0, ... }, { 0, ... }, { 0, POLY_INT_CST [2, 2], 1,
POLY_INT_CST [3, 2], 2, POLY_INT_CST [4, 2], ... }>;
isn't folded. It should work even for (some) non-uniform vectors to permute,
no?
