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Re: Fixed incorrect TARGET_MEM_REF alignment (PR 84419)
- From: Richard Biener <richard dot guenther at gmail dot com>
- To: gcc-patches at gcc dot gnu dot org,Richard Sandiford <richard dot sandiford at linaro dot org>
- Date: Tue, 20 Feb 2018 14:25:20 +0100
- Subject: Re: Fixed incorrect TARGET_MEM_REF alignment (PR 84419)
- Authentication-results: sourceware.org; auth=none
- References: <87po50ro6r.fsf@linaro.org>
On February 20, 2018 10:43:40 AM GMT+01:00, Richard Sandiford <richard.sandiford@linaro.org> wrote:
>expand_call_mem_ref checks for TARGET_MEM_REFs that have compatible
>type, but it didn't then go on to install the specific type we need,
>which might have different alignment due to:
>
> if (TYPE_ALIGN (type) != align)
> type = build_aligned_type (type, align);
>
>This was causing masked stores to be incorrectly marked as
>aligned on AVX512.
>
>Tested on aarch64-linux-gnu, x86_64-linux-gnu and powerpc64-linux-gnu.
>Also tested by Alexander on AVX512 hw. OK to install?
OK.
Richard.
>Richard
>
>
>2018-02-20 Richard Sandiford <richard.sandiford@linaro.org>
>
>gcc/
> PR tree-optimization/84419
> * internal-fn.c (expand_call_mem_ref): Create a TARGET_MEM_REF
> with the required type if its current type is compatible but
> different.
>
>gcc/testsuite/
> PR tree-optimization/84419
> * gcc.dg/vect/pr84419.c: New test.
>
>Index: gcc/internal-fn.c
>===================================================================
>--- gcc/internal-fn.c 2018-01-13 18:01:51.235735290 +0000
>+++ gcc/internal-fn.c 2018-02-20 09:40:47.547217244 +0000
>@@ -2444,11 +2444,14 @@ expand_call_mem_ref (tree type, gcall *s
> && types_compatible_p (TREE_TYPE (mem), type))
> {
> tree offset = TMR_OFFSET (mem);
>- if (alias_ptr_type != TREE_TYPE (offset) || !integer_zerop
>(offset))
>+ if (type != TREE_TYPE (mem)
>+ || alias_ptr_type != TREE_TYPE (offset)
>+ || !integer_zerop (offset))
> {
> mem = copy_node (mem);
> TMR_OFFSET (mem) = wide_int_to_tree (alias_ptr_type,
> wi::to_poly_wide (offset));
>+ TREE_TYPE (mem) = type;
> }
> return mem;
> }
>Index: gcc/testsuite/gcc.dg/vect/pr84419.c
>===================================================================
>--- /dev/null 2018-02-19 19:34:42.906488063 +0000
>+++ gcc/testsuite/gcc.dg/vect/pr84419.c 2018-02-20 09:40:47.548217201
>+0000
>@@ -0,0 +1,21 @@
>+#include <string.h>
>+
>+#define SIZE 400
>+
>+int foo[SIZE];
>+char bar[SIZE];
>+
>+void __attribute__ ((noinline)) foo_func(void)
>+{
>+ int i;
>+ for (i = 1; i < SIZE; i++)
>+ if (bar[i])
>+ foo[i] = 1;
>+}
>+
>+int main()
>+{
>+ memset(bar, 1, sizeof(bar));
>+ foo_func();
>+ return 0;
>+}