From 79f512ffebee22885684ff63bc3d66e7e6db9b4b Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Mon, 27 Mar 2017 08:07:49 +0000 Subject: [PATCH] re PR tree-optimization/80170 (SLP vectorization creates aligned access) 2017-03-27 Richard Biener PR tree-optimization/80170 * tree-vect-data-refs.c (vect_compute_data_ref_alignment): Make sure DR/SCEV didnt fold in constants we do not see when looking at the reference base alignment. * gcc.dg/pr80170.c: New testcase. From-SVN: r246491 --- gcc/ChangeLog | 7 ++++++ gcc/testsuite/ChangeLog | 5 ++++ gcc/testsuite/gcc.dg/pr80170.c | 42 ++++++++++++++++++++++++++++++++++ gcc/tree-vect-data-refs.c | 15 +++++++++--- 4 files changed, 66 insertions(+), 3 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/pr80170.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 3ef30163ab9..8dcd8975935 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,10 @@ +2017-03-27 Richard Biener + + PR tree-optimization/80170 + * tree-vect-data-refs.c (vect_compute_data_ref_alignment): Make + sure DR/SCEV didnt fold in constants we do not see when looking + at the reference base alignment. + 2017-03-27 Richard Biener PR middle-end/80171 diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 65c8310a7f9..0b04afeec54 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2017-03-27 Richard Biener + + PR tree-optimization/80170 + * gcc.dg/pr80170.c: New testcase. + 2017-03-27 Richard Biener PR middle-end/80171 diff --git a/gcc/testsuite/gcc.dg/pr80170.c b/gcc/testsuite/gcc.dg/pr80170.c new file mode 100644 index 00000000000..5ffd866c588 --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr80170.c @@ -0,0 +1,42 @@ +/* { dg-do run } */ +/* { dg-options "-fgimple -O2 -ftree-slp-vectorize" } */ + +struct A +{ + void * a; + void * b; +}; + +struct __attribute__((aligned(16))) B +{ + void * pad; + void * misaligned; + void * pad2; + + struct A a; +}; + +__attribute__((noclone, noinline)) +void __GIMPLE (startwith("slp")) +NullB (void * misalignedPtr) +{ + struct B * b; + + bb_2: +#if __SIZEOF_LONG__ == 8 + b_2 = misalignedPtr_1(D) + 18446744073709551608ul; +#else + b_2 = misalignedPtr_1(D) + 4294967292ul; +#endif + __MEM (b_2).a.a = _Literal (void *) 0; + __MEM (b_2).a.b = _Literal (void *) 0; + return; + +} + +int main() +{ + struct B b; + NullB (&b.misaligned); + return 0; +} diff --git a/gcc/tree-vect-data-refs.c b/gcc/tree-vect-data-refs.c index 29164d1b53b..3d1d7e7f918 100644 --- a/gcc/tree-vect-data-refs.c +++ b/gcc/tree-vect-data-refs.c @@ -779,7 +779,7 @@ vect_compute_data_ref_alignment (struct data_reference *dr) base = ref; while (handled_component_p (base)) base = TREE_OPERAND (base, 0); - unsigned int base_alignment; + unsigned int base_alignment = 0; unsigned HOST_WIDE_INT base_bitpos; get_object_alignment_1 (base, &base_alignment, &base_bitpos); /* As data-ref analysis strips the MEM_REF down to its base operand @@ -788,8 +788,17 @@ vect_compute_data_ref_alignment (struct data_reference *dr) DR_BASE_ADDRESS. */ if (TREE_CODE (base) == MEM_REF) { - base_bitpos -= mem_ref_offset (base).to_short_addr () * BITS_PER_UNIT; - base_bitpos &= (base_alignment - 1); + /* Note all this only works if DR_BASE_ADDRESS is the same as + MEM_REF operand zero, otherwise DR/SCEV analysis might have factored + in other offsets. We need to rework DR to compute the alingment + of DR_BASE_ADDRESS as long as all information is still available. */ + if (operand_equal_p (TREE_OPERAND (base, 0), base_addr, 0)) + { + base_bitpos -= mem_ref_offset (base).to_short_addr () * BITS_PER_UNIT; + base_bitpos &= (base_alignment - 1); + } + else + base_bitpos = BITS_PER_UNIT; } if (base_bitpos != 0) base_alignment = base_bitpos & -base_bitpos; -- 2.30.2