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re PR middle-end/24427 (missing optimization opportunity with binary operators)

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PR middle-end/24427
	* fold-const.c (fold_binary) <BIT_IOR_EXPR>: Transform (X&C1)|C2
	into (X,C2) if C1 is a subset of the bits of C2.  Transform
	(X&C1)|C2 into X|C2 if C1|C2 == ~0.  Canonicalize (X&C1)|C2 as
	(X&(C1&~C2))|C2.
	<BIT_AND_EXPR>: Canonicalize (X|C1)&C2 as (X&C2)|(C1&C2).

	* gcc.dg/tree-ssa/andor-1.c: New test case.

From-SVN: r110918
This commit is contained in:
Roger Sayle 2006-02-13 18:33:32 +00:00 committed by Roger Sayle
parent 4c553323a6
commit 840992bdc2
4 changed files with 136 additions and 0 deletions
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9
gcc/ChangeLog
View File

@ -1,3 +1,12 @@
2006-02-13 Roger Sayle <roger@eyesopen.com>
PR middle-end/24427
* fold-const.c (fold_binary) <BIT_IOR_EXPR>: Transform (X&C1)|C2
into (X,C2) if C1 is a subset of the bits of C2. Transform
(X&C1)|C2 into X|C2 if C1|C2 == ~0. Canonicalize (X&C1)|C2 as
(X&(C1&~C2))|C2.
<BIT_AND_EXPR>: Canonicalize (X|C1)&C2 as (X&C2)|(C1&C2).
2006-02-13 Josh Conner <jconner@apple.com>
PR target/25376

57
gcc/fold-const.c
View File

@ -8114,6 +8114,53 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
return omit_one_operand (type, t1, arg0);
}
/* Canonicalize (X & C1) | C2. */
if (TREE_CODE (arg0) == BIT_AND_EXPR
&& TREE_CODE (arg1) == INTEGER_CST
&& TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
{
unsigned HOST_WIDE_INT hi1, lo1, hi2, lo2, mlo, mhi;
int width = TYPE_PRECISION (type);
hi1 = TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1));
lo1 = TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1));
hi2 = TREE_INT_CST_HIGH (arg1);
lo2 = TREE_INT_CST_LOW (arg1);
/* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
if ((hi1 & hi2) == hi1 && (lo1 & lo2) == lo1)
return omit_one_operand (type, arg1, TREE_OPERAND (arg0, 0));
if (width > HOST_BITS_PER_WIDE_INT)
{
mhi = (unsigned HOST_WIDE_INT) -1
>> (2 * HOST_BITS_PER_WIDE_INT - width);
mlo = -1;
}
else
{
mhi = 0;
mlo = (unsigned HOST_WIDE_INT) -1
>> (HOST_BITS_PER_WIDE_INT - width);
}
/* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
if ((~(hi1 | hi2) & mhi) == 0 && (~(lo1 | lo2) & mlo) == 0)
return fold_build2 (BIT_IOR_EXPR, type,
TREE_OPERAND (arg0, 0), arg1);
/* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2. */
hi1 &= mhi;
lo1 &= mlo;
if ((hi1 & ~hi2) != hi1 || (lo1 & ~lo2) != lo1)
return fold_build2 (BIT_IOR_EXPR, type,
fold_build2 (BIT_AND_EXPR, type,
TREE_OPERAND (arg0, 0),
build_int_cst_wide (type,
lo1 & ~lo2,
hi1 & ~hi2)),
arg1);
}
t1 = distribute_bit_expr (code, type, arg0, arg1);
if (t1 != NULL_TREE)
return t1;
@ -8256,6 +8303,16 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
&& operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0))
return omit_one_operand (type, integer_zero_node, arg0);
/* Canonicalize (X | C1) & C2 as (X & C2) | (C1 & C2). */
if (TREE_CODE (arg0) == BIT_IOR_EXPR
&& TREE_CODE (arg1) == INTEGER_CST
&& TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
return fold_build2 (BIT_IOR_EXPR, type,
fold_build2 (BIT_AND_EXPR, type,
TREE_OPERAND (arg0, 0), arg1),
fold_build2 (BIT_AND_EXPR, type,
TREE_OPERAND (arg0, 1), arg1));
t1 = distribute_bit_expr (code, type, arg0, arg1);
if (t1 != NULL_TREE)
return t1;

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2006-02-13 Roger Sayle <roger@eyesopen.com>
PR middle-end/24427
* gcc.dg/tree-ssa/andor-1.c: New test case.
2006-02-13 Josh Conner <jconner@apple.com>
PR target/25376

65
gcc/testsuite/gcc.dg/tree-ssa/andor-1.c Normal file
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@ -0,0 +1,65 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-original" } */
unsigned int test1(unsigned int a)
{
return (a & 1) | 1;
}
int test2(int b)
{
return (b & 1) | 1;
}
unsigned int test3(unsigned int c)
{
return (c | 1) & 1;
}
int test4(int d)
{
return (d | 1) & 1;
}
unsigned int test5(unsigned int e)
{
return (e | 4) & 6;
}
int test6(int f)
{
return (f | 4) & 6;
}
unsigned int test7(unsigned int g)
{
return (g & -2) | 1;
}
int test8(int h)
{
return (h & -2) | 1;
}
unsigned int test9(unsigned int i)
{
return (i & 3) | 1;
}
int test10(int j)
{
return (j & 3) | 1;
}
/* { dg-final { scan-tree-dump-times "a \& 1 \\| 1" 0 "original" } } */
/* { dg-final { scan-tree-dump-times "b \& 1 \\| 1" 0 "original" } } */
/* { dg-final { scan-tree-dump-times "\\(c \\| 1\\) \& 1" 0 "original" } } */
/* { dg-final { scan-tree-dump-times "\\(d \\| 1\\) \& 1" 0 "original" } } */
/* { dg-final { scan-tree-dump-times "e \& 2 \\| 4" 1 "original" } } */
/* { dg-final { scan-tree-dump-times "f \& 2 \\| 4" 1 "original" } } */
/* { dg-final { scan-tree-dump-times "g \\| 1" 1 "original" } } */
/* { dg-final { scan-tree-dump-times "h \\| 1" 1 "original" } } */
/* { dg-final { scan-tree-dump-times "i \& 2 \\| 1" 1 "original" } } */
/* { dg-final { scan-tree-dump-times "j \& 2 \\| 1" 1 "original" } } */
/* { dg-final { cleanup-tree-dump "original" } } */