From c9aa91088d2ab49a29c5588f62657afd7a84139e Mon Sep 17 00:00:00 2001 From: Joern Rennecke Date: Thu, 20 Dec 2018 23:00:00 +0000 Subject: [PATCH] tree-vect-data-refs.c (vect_enhance_data_refs_alignment): Don't do versioning for data accesses with misaligned step. 2018-12-20 Joern Rennecke * tree-vect-data-refs.c (vect_enhance_data_refs_alignment): Don't do versioning for data accesses with misaligned step. From-SVN: r267314 --- gcc/ChangeLog | 5 +++++ gcc/tree-vect-data-refs.c | 14 ++++++++++++++ 2 files changed, 19 insertions(+) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index acadee92ef3..2c12ca2ae26 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2018-12-20 Joern Rennecke + + * tree-vect-data-refs.c (vect_enhance_data_refs_alignment): Don't do + versioning for data accesses with misaligned step. + 2018-12-20 H.J. Lu PR c/51628 diff --git a/gcc/tree-vect-data-refs.c b/gcc/tree-vect-data-refs.c index deb7121623e..6cd2c30ef4b 100644 --- a/gcc/tree-vect-data-refs.c +++ b/gcc/tree-vect-data-refs.c @@ -2160,6 +2160,20 @@ vect_enhance_data_refs_alignment (loop_vec_info loop_vinfo) break; } + /* Forcing alignment in the first iteration is no good if + we don't keep it across iterations. For now, just disable + versioning in this case. + ?? We could actually unroll the loop to archive the required + overall step alignemnt, and forcing the alignment could be + done by doing some iterations of the non-vectorized loop. */ + if (!multiple_p (LOOP_VINFO_VECT_FACTOR (loop_vinfo) + * DR_STEP_ALIGNMENT (dr), + DR_TARGET_ALIGNMENT (dr))) + { + do_versioning = false; + break; + } + /* The rightmost bits of an aligned address must be zeros. Construct the mask needed for this test. For example, GET_MODE_SIZE for the vector mode V4SI is 16 bytes so the -- 2.30.2