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Designate the widest case label to be the default label

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gcc/ChangeLog:

	* gimple.c (preprocess_case_label_vec_for_gimple): When the case
	labels are exhaustive, designate the label with the widest
	range to be the default label.

gcc/testsuite/ChangeLog:

	* gcc.dg/switch-10.c: New test.

From-SVN: r239146
This commit is contained in:
Patrick Palka 2016-08-04 18:11:08 +00:00
parent 42183d034d
commit 938da3a58b
4 changed files with 45 additions and 1 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2016-08-04 Patrick Palka <ppalka@gcc.gnu.org>
* gimple.c (preprocess_case_label_vec_for_gimple): When the case
labels are exhaustive, designate the label with the widest
range to be the default label.
2016-08-04 Andrew Pinski <apinski@cavium.com>
* config/aarch64/aarch64.c (thunderx_vector_cost): New variable.

14
gcc/gimple.c
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@ -2946,18 +2946,30 @@ preprocess_case_label_vec_for_gimple (vec<tree> labels,
high = CASE_LOW (labels[len - 1]);
if (tree_int_cst_equal (high, TYPE_MAX_VALUE (index_type)))
{
tree widest_label = labels[0];
for (i = 1; i < len; i++)
{
high = CASE_LOW (labels[i]);
low = CASE_HIGH (labels[i - 1]);
if (!low)
low = CASE_LOW (labels[i - 1]);
if (CASE_HIGH (labels[i]) != NULL_TREE
&& (CASE_HIGH (widest_label) == NULL_TREE
|| wi::gtu_p (wi::sub (CASE_HIGH (labels[i]),
CASE_LOW (labels[i])),
wi::sub (CASE_HIGH (widest_label),
CASE_LOW (widest_label)))))
widest_label = labels[i];
if (wi::add (low, 1) != high)
break;
}
if (i == len)
{
tree label = CASE_LABEL (labels[0]);
/* Designate the label with the widest range to be the
default label. */
tree label = CASE_LABEL (widest_label);
default_case = build_case_label (NULL_TREE, NULL_TREE,
label);
}

4
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,7 @@
2016-08-04 Patrick Palka <ppalka@gcc.gnu.org>
* gcc.dg/switch-10.c: New test.
2016-08-04 James Greenhalgh <james.greenhalgh@arm.com>
* gcc.c-torture/execute/pr70903.c: Remove duplicate test body.

22
gcc/testsuite/gcc.dg/switch-10.c Normal file
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@ -0,0 +1,22 @@
/* { dg-options "-O2 -fdump-tree-cfg" } */
/* { dg-final { scan-tree-dump "case 0:" "cfg" } } */
/* { dg-final { scan-tree-dump-not "case 1 ... 255:" "cfg" } } */
#include <stdint.h>
void foo (void);
void bar (void);
void
test (uint8_t ch)
{
switch (ch)
{
case 0:
foo ();
break;
case 1 ... 255:
bar ();
break;
}
}