From 2182274f510c180ea92a4f826a0f6cf5f1f55b66 Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Thu, 14 Jan 2021 14:08:41 +0100 Subject: [PATCH] tree-optimization/98674 - improve dependence analysis This improves dependence analysis on refs that access the same array but with different typed but same sized accesses. That's obviously safe for the case of types that cannot have any access function based off them. For the testcase this is signed short vs. unsigned short. 2021-01-14 Richard Biener PR tree-optimization/98674 * tree-data-ref.c (base_supports_access_fn_components_p): New. (initialize_data_dependence_relation): For two bases without possible access fns resort to type size equality when determining shape compatibility. * gcc.dg/vect/pr98674.c: New testcase. --- gcc/testsuite/gcc.dg/vect/pr98674.c | 16 ++++++++++++++++ gcc/tree-data-ref.c | 26 ++++++++++++++++++++++++-- 2 files changed, 40 insertions(+), 2 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/vect/pr98674.c diff --git a/gcc/testsuite/gcc.dg/vect/pr98674.c b/gcc/testsuite/gcc.dg/vect/pr98674.c new file mode 100644 index 00000000000..0f1b6cb060b --- /dev/null +++ b/gcc/testsuite/gcc.dg/vect/pr98674.c @@ -0,0 +1,16 @@ +/* { dg-do compile } */ +/* { dg-additional-options "-msse2" { target sse2 } } */ + +void swap(short *p, int cnt) +{ + while (cnt-- > 0) + { + *p = ((*p << 8) & 0xFF00) | ((*p >> 8) & 0x00FF); + ++p; + } +} + +/* Dependence analysis should not fail. */ +/* { dg-final { scan-tree-dump "dependence distance == 0" "vect" } } */ +/* On x86 with SSE2 we can vectorize this with psllw/psrlw. */ +/* { dg-final { scan-tree-dump "loop vectorized" "vect" { target sse2 } } } */ diff --git a/gcc/tree-data-ref.c b/gcc/tree-data-ref.c index 394470af757..65fe6d5da91 100644 --- a/gcc/tree-data-ref.c +++ b/gcc/tree-data-ref.c @@ -1291,6 +1291,23 @@ access_fn_component_p (tree op) } } +/* Returns whether BASE can have a access_fn_component_p with BASE + as base. */ + +static bool +base_supports_access_fn_components_p (tree base) +{ + switch (TREE_CODE (TREE_TYPE (base))) + { + case COMPLEX_TYPE: + case ARRAY_TYPE: + case RECORD_TYPE: + return true; + default: + return false; + } +} + /* Determines the base object and the list of indices of memory reference DR, analyzed in LOOP and instantiated before NEST. */ @@ -3272,8 +3289,13 @@ initialize_data_dependence_relation (struct data_reference *a, && full_seq.start_b + full_seq.length == num_dimensions_b && DR_UNCONSTRAINED_BASE (a) == DR_UNCONSTRAINED_BASE (b) && operand_equal_p (base_a, base_b, OEP_ADDRESS_OF) - && types_compatible_p (TREE_TYPE (base_a), - TREE_TYPE (base_b)) + && (types_compatible_p (TREE_TYPE (base_a), + TREE_TYPE (base_b)) + || (!base_supports_access_fn_components_p (base_a) + && !base_supports_access_fn_components_p (base_b) + && operand_equal_p + (TYPE_SIZE (TREE_TYPE (base_a)), + TYPE_SIZE (TREE_TYPE (base_b)), 0))) && (!loop_nest.exists () || (object_address_invariant_in_loop_p (loop_nest[0], base_a)))); -- 2.30.2