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re PR rtl-optimization/63843 (wrong code generation at -O1 and higher)

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PR rtl-optimization/63843
	* simplify-rtx.c (simplify_binary_operation_1) <case ASHIFTRT>: For
	optimization of ashiftrt of subreg of lshiftrt, check that code
	is ASHIFTRT.

	* gcc.c-torture/execute/pr63843.c: New test.

From-SVN: r217753
This commit is contained in:
Jakub Jelinek 2014-11-19 09:18:53 +01:00 committed by Jakub Jelinek
parent 26c87b1a64
commit 05f9c67507
4 changed files with 79 additions and 37 deletions
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7
gcc/ChangeLog
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@ -1,3 +1,10 @@
2014-11-19 Jakub Jelinek <jakub@redhat.com>
PR rtl-optimization/63843
* simplify-rtx.c (simplify_binary_operation_1) <case ASHIFTRT>: For
optimization of ashiftrt of subreg of lshiftrt, check that code
is ASHIFTRT.
2014-11-18 Andrew MacLeod <amacleod@redhat.com>
* attribs.c (decl_attributes): Remove always true condition,

73
gcc/simplify-rtx.c
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@ -3105,43 +3105,42 @@ simplify_binary_operation_1 (enum rtx_code code, machine_mode mode,
&& ! side_effects_p (op1))
return op0;
/* Given:
scalar modes M1, M2
scalar constants c1, c2
size (M2) > size (M1)
c1 == size (M2) - size (M1)
optimize:
(ashiftrt:M1 (subreg:M1 (lshiftrt:M2 (reg:M2)
(const_int <c1>))
<low_part>)
(const_int <c2>))
to:
(subreg:M1 (ashiftrt:M2 (reg:M2)
(const_int <c1 + c2>))
<low_part>). */
if (!VECTOR_MODE_P (mode)
&& SUBREG_P (op0)
&& CONST_INT_P (op1)
&& (GET_CODE (SUBREG_REG (op0)) == LSHIFTRT)
&& !VECTOR_MODE_P (GET_MODE (SUBREG_REG (op0)))
&& CONST_INT_P (XEXP (SUBREG_REG (op0), 1))
&& (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (op0)))
> GET_MODE_BITSIZE (mode))
&& (INTVAL (XEXP (SUBREG_REG (op0), 1))
== (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (op0)))
- GET_MODE_BITSIZE (mode)))
&& subreg_lowpart_p (op0))
{
rtx tmp = GEN_INT (INTVAL (XEXP (SUBREG_REG (op0), 1))
+ INTVAL (op1));
machine_mode inner_mode = GET_MODE (SUBREG_REG (op0));
tmp = simplify_gen_binary (ASHIFTRT,
GET_MODE (SUBREG_REG (op0)),
XEXP (SUBREG_REG (op0), 0),
tmp);
return simplify_gen_subreg (mode, tmp, inner_mode,
subreg_lowpart_offset (mode,
inner_mode));
}
scalar modes M1, M2
scalar constants c1, c2
size (M2) > size (M1)
c1 == size (M2) - size (M1)
optimize:
(ashiftrt:M1 (subreg:M1 (lshiftrt:M2 (reg:M2) (const_int <c1>))
<low_part>)
(const_int <c2>))
to:
(subreg:M1 (ashiftrt:M2 (reg:M2) (const_int <c1 + c2>))
<low_part>). */
if (code == ASHIFTRT
&& !VECTOR_MODE_P (mode)
&& SUBREG_P (op0)
&& CONST_INT_P (op1)
&& GET_CODE (SUBREG_REG (op0)) == LSHIFTRT
&& !VECTOR_MODE_P (GET_MODE (SUBREG_REG (op0)))
&& CONST_INT_P (XEXP (SUBREG_REG (op0), 1))
&& (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (op0)))
> GET_MODE_BITSIZE (mode))
&& (INTVAL (XEXP (SUBREG_REG (op0), 1))
== (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (op0)))
- GET_MODE_BITSIZE (mode)))
&& subreg_lowpart_p (op0))
{
rtx tmp = GEN_INT (INTVAL (XEXP (SUBREG_REG (op0), 1))
+ INTVAL (op1));
machine_mode inner_mode = GET_MODE (SUBREG_REG (op0));
tmp = simplify_gen_binary (ASHIFTRT,
GET_MODE (SUBREG_REG (op0)),
XEXP (SUBREG_REG (op0), 0),
tmp);
return simplify_gen_subreg (mode, tmp, inner_mode,
subreg_lowpart_offset (mode,
inner_mode));
}
canonicalize_shift:
if (SHIFT_COUNT_TRUNCATED && CONST_INT_P (op1))
{

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2014-11-19 Jakub Jelinek <jakub@redhat.com>
PR rtl-optimization/63843
* gcc.c-torture/execute/pr63843.c: New test.
2014-11-18 James Greenhalgh <james.greenhalgh@arm.com>
PR target/63937

31
gcc/testsuite/gcc.c-torture/execute/pr63843.c Normal file
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@ -0,0 +1,31 @@
/* PR rtl-optimization/63843 */
static inline __attribute__ ((always_inline))
unsigned short foo (unsigned short v)
{
return (v << 8) | (v >> 8);
}
unsigned short __attribute__ ((noinline, noclone, hot))
bar (unsigned char *x)
{
unsigned int a;
unsigned short b;
__builtin_memcpy (&a, &x[0], sizeof (a));
a ^= 0x80808080U;
__builtin_memcpy (&x[0], &a, sizeof (a));
__builtin_memcpy (&b, &x[2], sizeof (b));
return foo (b);
}
int
main ()
{
unsigned char x[8] = { 0x01, 0x01, 0x01, 0x01 };
if (__CHAR_BIT__ == 8
&& sizeof (short) == 2
&& sizeof (int) == 4
&& bar (x) != 0x8181U)
__builtin_abort ();
return 0;
}