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re PR rtl-optimization/70429 (Wrong code with -O1.)

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PR rtl-optimization/70429
	* combine.c (simplify_shift_const_1): For ASHIFTRT don't optimize
	(cst1 >> count) >> cst2 into (cst1 >> cst2) >> count if
	mode != result_mode.

	* gcc.c-torture/execute/pr70429.c: New test.

From-SVN: r234531
This commit is contained in:
Jakub Jelinek 2016-03-29 20:49:00 +02:00 committed by Jakub Jelinek
parent e0bffbbb59
commit a362f023e5
4 changed files with 30 additions and 0 deletions
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5
gcc/ChangeLog
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@ -1,5 +1,10 @@
2016-03-29 Jakub Jelinek <jakub@redhat.com>
PR rtl-optimization/70429
* combine.c (simplify_shift_const_1): For ASHIFTRT don't optimize
(cst1 >> count) >> cst2 into (cst1 >> cst2) >> count if
mode != result_mode.
PR c++/70353
* tree-inline.c (remap_decls): Don't add_local_decl if
cfun is null.

5
gcc/combine.c
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@ -10533,6 +10533,11 @@ simplify_shift_const_1 (enum rtx_code code, machine_mode result_mode,
>> orig_count, result_mode,
&complement_p))
break;
/* For ((int) (cstLL >> count)) >> cst2 just give up. Queuing
up outer sign extension (often left and right shift) is
hardly more efficient than the original. See PR70429. */
if (code == ASHIFTRT && mode != result_mode)
break;
rtx new_rtx = simplify_const_binary_operation (code, mode,
XEXP (varop, 0),

3
gcc/testsuite/ChangeLog
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@ -1,5 +1,8 @@
2016-03-29 Jakub Jelinek <jakub@redhat.com>
PR rtl-optimization/70429
* gcc.c-torture/execute/pr70429.c: New test.
PR tree-optimization/70405
* gcc.dg/pr70405.c: New test.

17
gcc/testsuite/gcc.c-torture/execute/pr70429.c Normal file
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@ -0,0 +1,17 @@
/* PR rtl-optimization/70429 */
__attribute__((noinline, noclone)) int
foo (int a)
{
return (int) (0x14ff6e2207db5d1fLL >> a) >> 4;
}
int
main ()
{
if (sizeof (int) != 4 || sizeof (long long) != 8 || __CHAR_BIT__ != 8)
return 0;
if (foo (1) != 0x3edae8 || foo (2) != -132158092)
__builtin_abort ();
return 0;
}