From 00dc7877ee02634d4837d024e36b55bef6b9d49c Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Tue, 18 Jan 2022 09:06:13 +0100 Subject: [PATCH] tree-optimization/104064 - UBSAN issue in vect dataref analysis Since we order DRs after DR_INIT we know the difference will be positive and thus can avoid signed overflow issues by using unsigned arithmetic to produce the known unsigned result. 2022-01-18 Richard Biener PR tree-optimization/104064 * tree-vect-data-refs.cc (vect_analyze_data_ref_accesses): Check DR_INIT fits in a signed HWI, represent the difference from the first DR in unsigned. --- gcc/tree-vect-data-refs.cc | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/gcc/tree-vect-data-refs.cc b/gcc/tree-vect-data-refs.cc index dd20ed9..09223ba 100644 --- a/gcc/tree-vect-data-refs.cc +++ b/gcc/tree-vect-data-refs.cc @@ -3172,8 +3172,8 @@ vect_analyze_data_ref_accesses (vec_info *vinfo, break; /* Check that the DR_INITs are compile-time constants. */ - if (TREE_CODE (DR_INIT (dra)) != INTEGER_CST - || TREE_CODE (DR_INIT (drb)) != INTEGER_CST) + if (!tree_fits_shwi_p (DR_INIT (dra)) + || !tree_fits_shwi_p (DR_INIT (drb))) break; /* Different .GOMP_SIMD_LANE calls still give the same lane, @@ -3203,15 +3203,18 @@ vect_analyze_data_ref_accesses (vec_info *vinfo, { /* If init_b == init_a + the size of the type * k, we have an interleaving, and DRA is accessed before DRB. */ - HOST_WIDE_INT type_size_a = tree_to_uhwi (sza); + unsigned HOST_WIDE_INT type_size_a = tree_to_uhwi (sza); if (type_size_a == 0 - || (init_b - init_a) % type_size_a != 0) + || (((unsigned HOST_WIDE_INT)init_b - init_a) + % type_size_a != 0)) break; /* If we have a store, the accesses are adjacent. This splits groups into chunks we support (we don't support vectorization of stores with gaps). */ - if (!DR_IS_READ (dra) && init_b - init_prev != type_size_a) + if (!DR_IS_READ (dra) + && (((unsigned HOST_WIDE_INT)init_b - init_prev) + != type_size_a)) break; /* If the step (if not zero or non-constant) is smaller than the @@ -3222,7 +3225,7 @@ vect_analyze_data_ref_accesses (vec_info *vinfo, unsigned HOST_WIDE_INT step = absu_hwi (tree_to_shwi (DR_STEP (dra))); if (step != 0 - && step <= (unsigned HOST_WIDE_INT)(init_b - init_a)) + && step <= ((unsigned HOST_WIDE_INT)init_b - init_a)) break; } } -- 2.7.4