On Fri, Jan 19, 2018 at 10:45 AM, Richard Sandiford
<richard.sandif...@linaro.org> wrote:
> This testcase ICEd because we converted the initial value of an
> induction to the vector element type even for nested inductions.
> This isn't necessary because the initial expression is vectorised
> normally, and it meant that init_expr was no longer the original
> statement operand by the time we called vect_get_vec_def_for_operand.
>
> Also, adding the conversion code here made the existing SLP conversion
> redundant.
>
> It looks like something went wrong when rebasing the peeling via masks
> work on top of the support for SLP reductions, sorry about that.
>
> Tested on aarch64-linux-gnu, x86_64-linux-gnu and powerpc64le-linux-gnu.
> OK to install?
Ok.
Richard.
> Richard
>
>
> 2018-01-19 Richard Sandiford <richard.sandif...@linaro.org>
>
> gcc/
> PR tree-optimization/83914
> * tree-vect-loop.c (vectorizable_induction): Don't convert
> init_expr or apply the peeling adjustment for inductions
> that are nested within the vectorized loop. Remove redundant
> conversion code.
>
> gcc/testsuite/
> PR tree-optimization/83914
> * gcc.dg/vect/pr83914.c: New test.
>
> Index: gcc/tree-vect-loop.c
> ===================================================================
> --- gcc/tree-vect-loop.c 2018-01-16 15:13:24.938622242 +0000
> +++ gcc/tree-vect-loop.c 2018-01-19 09:36:33.409191362 +0000
> @@ -7678,28 +7678,33 @@ vectorizable_induction (gimple *phi,
> init_expr = PHI_ARG_DEF_FROM_EDGE (phi,
> loop_preheader_edge (iv_loop));
>
> - /* Convert the initial value and step to the desired type. */
> stmts = NULL;
> - init_expr = gimple_convert (&stmts, TREE_TYPE (vectype), init_expr);
> - step_expr = gimple_convert (&stmts, TREE_TYPE (vectype), step_expr);
> -
> - /* If we are using the loop mask to "peel" for alignment then we need
> - to adjust the start value here. */
> - tree skip_niters = LOOP_VINFO_MASK_SKIP_NITERS (loop_vinfo);
> - if (skip_niters != NULL_TREE)
> + if (!nested_in_vect_loop)
> {
> - if (FLOAT_TYPE_P (vectype))
> - skip_niters = gimple_build (&stmts, FLOAT_EXPR, TREE_TYPE (vectype),
> - skip_niters);
> - else
> - skip_niters = gimple_convert (&stmts, TREE_TYPE (vectype),
> - skip_niters);
> - tree skip_step = gimple_build (&stmts, MULT_EXPR, TREE_TYPE (vectype),
> - skip_niters, step_expr);
> - init_expr = gimple_build (&stmts, MINUS_EXPR, TREE_TYPE (vectype),
> - init_expr, skip_step);
> + /* Convert the initial value to the desired type. */
> + tree new_type = TREE_TYPE (vectype);
> + init_expr = gimple_convert (&stmts, new_type, init_expr);
> +
> + /* If we are using the loop mask to "peel" for alignment then we need
> + to adjust the start value here. */
> + tree skip_niters = LOOP_VINFO_MASK_SKIP_NITERS (loop_vinfo);
> + if (skip_niters != NULL_TREE)
> + {
> + if (FLOAT_TYPE_P (vectype))
> + skip_niters = gimple_build (&stmts, FLOAT_EXPR, new_type,
> + skip_niters);
> + else
> + skip_niters = gimple_convert (&stmts, new_type, skip_niters);
> + tree skip_step = gimple_build (&stmts, MULT_EXPR, new_type,
> + skip_niters, step_expr);
> + init_expr = gimple_build (&stmts, MINUS_EXPR, new_type,
> + init_expr, skip_step);
> + }
> }
>
> + /* Convert the step to the desired type. */
> + step_expr = gimple_convert (&stmts, TREE_TYPE (vectype), step_expr);
> +
> if (stmts)
> {
> new_bb = gsi_insert_seq_on_edge_immediate (pe, stmts);
> @@ -7718,15 +7723,6 @@ vectorizable_induction (gimple *phi,
> /* Enforced above. */
> unsigned int const_nunits = nunits.to_constant ();
>
> - /* Convert the init to the desired type. */
> - stmts = NULL;
> - init_expr = gimple_convert (&stmts, TREE_TYPE (vectype), init_expr);
> - if (stmts)
> - {
> - new_bb = gsi_insert_seq_on_edge_immediate (pe, stmts);
> - gcc_assert (!new_bb);
> - }
> -
> /* Generate [VF*S, VF*S, ... ]. */
> if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (step_expr)))
> {
> Index: gcc/testsuite/gcc.dg/vect/pr83914.c
> ===================================================================
> --- /dev/null 2018-01-19 09:30:49.543814408 +0000
> +++ gcc/testsuite/gcc.dg/vect/pr83914.c 2018-01-19 09:36:33.405191141 +0000
> @@ -0,0 +1,15 @@
> +/* { dg-do compile } */
> +/* { dg-additional-options "-O3" } */
> +
> +struct s { struct s *ptrs[16]; } *a, *b;
> +int c;
> +void
> +foo (int n)
> +{
> + for (; n; a = b, n--)
> + {
> + b = a + 1;
> + for (c = 8; c; c--)
> + a->ptrs[c] = b;
> + }
> +}
