129 lines
3.9 KiB
Diff
129 lines
3.9 KiB
Diff
2009-03-18 Jakub Jelinek <jakub@redhat.com>
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* builtins.c (fold_builtin_memory_op): Optimize memmove
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into memcpy if we can prove source and destination don't overlap.
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* gcc.dg/memmove-2.c: New test.
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* gcc.dg/memmove-3.c: New test.
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--- gcc/builtins.c.jj 2009-03-04 20:06:31.000000000 +0100
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+++ gcc/builtins.c 2009-03-18 18:19:28.000000000 +0100
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@@ -8882,17 +8882,74 @@ fold_builtin_memory_op (tree dest, tree
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really mandatory?
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If either SRC is readonly or length is 1, we can use memcpy. */
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- if (dest_align && src_align
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- && (readonly_data_expr (src)
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- || (host_integerp (len, 1)
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- && (MIN (src_align, dest_align) / BITS_PER_UNIT >=
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- tree_low_cst (len, 1)))))
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+ if (!dest_align || !src_align)
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+ return NULL_TREE;
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+ if (readonly_data_expr (src)
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+ || (host_integerp (len, 1)
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+ && (MIN (src_align, dest_align) / BITS_PER_UNIT >=
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+ tree_low_cst (len, 1))))
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{
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tree fn = implicit_built_in_decls[BUILT_IN_MEMCPY];
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if (!fn)
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return NULL_TREE;
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return build_call_expr (fn, 3, dest, src, len);
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}
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+
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+ /* If *src and *dest can't overlap, optimize into memcpy as well. */
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+ srcvar = build_fold_indirect_ref (src);
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+ destvar = build_fold_indirect_ref (dest);
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+ if (srcvar && !TREE_THIS_VOLATILE (srcvar)
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+ && destvar && !TREE_THIS_VOLATILE (destvar))
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+ {
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+ tree src_base, dest_base, fn;
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+ HOST_WIDE_INT src_offset = 0, dest_offset = 0;
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+ HOST_WIDE_INT size = -1;
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+ HOST_WIDE_INT maxsize = -1;
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+
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+ src_base = srcvar;
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+ if (handled_component_p (src_base))
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+ src_base = get_ref_base_and_extent (src_base, &src_offset,
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+ &size, &maxsize);
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+ dest_base = destvar;
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+ if (handled_component_p (dest_base))
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+ dest_base = get_ref_base_and_extent (dest_base, &dest_offset,
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+ &size, &maxsize);
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+ if (host_integerp (len, 1))
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+ {
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+ maxsize = tree_low_cst (len, 1);
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+ if (maxsize
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+ > INTTYPE_MAXIMUM (HOST_WIDE_INT) / BITS_PER_UNIT)
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+ maxsize = -1;
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+ else
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+ maxsize *= BITS_PER_UNIT;
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+ }
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+ else
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+ maxsize = -1;
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+ if (SSA_VAR_P (src_base)
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+ && SSA_VAR_P (dest_base))
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+ {
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+ if (operand_equal_p (src_base, dest_base, 0)
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+ && ranges_overlap_p (src_offset, maxsize,
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+ dest_offset, maxsize))
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+ return NULL_TREE;
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+ }
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+ else if (TREE_CODE (src_base) == INDIRECT_REF
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+ && TREE_CODE (dest_base) == INDIRECT_REF)
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+ {
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+ if (! operand_equal_p (TREE_OPERAND (src_base, 0),
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+ TREE_OPERAND (dest_base, 0), 0)
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+ || ranges_overlap_p (src_offset, maxsize,
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+ dest_offset, maxsize))
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+ return NULL_TREE;
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+ }
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+ else
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+ return NULL_TREE;
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+
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+ fn = implicit_built_in_decls[BUILT_IN_MEMCPY];
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+ if (!fn)
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+ return NULL_TREE;
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+ return build_call_expr (fn, 3, dest, src, len);
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+ }
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return NULL_TREE;
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}
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--- gcc/testsuite/gcc.dg/memmove-2.c.jj 2009-03-18 18:30:17.000000000 +0100
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+++ gcc/testsuite/gcc.dg/memmove-2.c 2009-03-18 18:30:49.000000000 +0100
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@@ -0,0 +1,16 @@
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+/* { dg-do compile } */
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+/* { dg-options "-O2 -fdump-tree-optimized" } */
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+/* { dg-final { scan-tree-dump-times "memmove" 0 "optimized" } } */
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+/* { dg-final { cleanup-tree-dump "optimized" } } */
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+
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+char a[40];
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+extern void bar (char *);
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+
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+void
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+foo (void)
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+{
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+ char b[10];
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+ __builtin_memmove (&a[0], &a[20], 20);
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+ __builtin_memmove (&b[1], &a[25], 9);
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+ bar (b);
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+}
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--- gcc/testsuite/gcc.dg/memmove-3.c.jj 2009-03-18 18:30:19.000000000 +0100
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+++ gcc/testsuite/gcc.dg/memmove-3.c 2009-03-18 18:31:01.000000000 +0100
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@@ -0,0 +1,16 @@
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+/* { dg-do compile } */
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+/* { dg-options "-O2 -fdump-tree-optimized" } */
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+/* { dg-final { scan-tree-dump-times "memmove" 3 "optimized" } } */
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+/* { dg-final { cleanup-tree-dump "optimized" } } */
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+
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+char a[40];
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+struct A { char a[30]; };
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+
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+void
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+foo (struct A *p, char *q, char *r)
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+{
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+ char b[10];
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+ __builtin_memmove (&a[1], &a[19], 20);
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+ __builtin_memmove (&p->a[1], &p->a[9], 10);
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+ __builtin_memmove (q, r, 9);
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+}
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