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re PR rtl-optimization/28173 (misses constant folding) 

PR rtl-optimization/28173
	* simplify-rtx.c (simplify_binary_operation_1) <IOR>:  Optimize
	(X & C1) | C2 as C2 when (C1 & C2) == C1 and X has no side-effects.
	Optimize (X & C1) | C2 as X | C2 when (C1 | C2) == ~0.
	Canonicalize (X & C1) | C2 as (X & (C1 & ~C2)) | C2.
	<AND>: Canonicalize (X | C1) & C2 as (X & C2) | (C1 & C2).

	* gcc.target/i386/andor-1.c: New test case.

From-SVN: r122116
This commit is contained in:
Roger Sayle 2007-02-19 00:54:29 +00:00 committed by Roger Sayle
parent 1b16dad6f4
commit 49e7a9d4b8
4 changed files with 63 additions and 0 deletions
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9
gcc/ChangeLog
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@ -1,3 +1,12 @@
2007-02-18 Roger Sayle <roger@eyesopen.com>
PR rtl-optimization/28173
* simplify-rtx.c (simplify_binary_operation_1) <IOR>: Optimize
(X & C1) | C2 as C2 when (C1 & C2) == C1 and X has no side-effects.
Optimize (X & C1) | C2 as X | C2 when (C1 | C2) == ~0.
Canonicalize (X & C1) | C2 as (X & (C1 & ~C2)) | C2.
<AND>: Canonicalize (X | C1) & C2 as (X & C2) | (C1 & C2).
2007-02-18 Kaveh R. Ghazi <ghazi@caip.rutgers.edu>
* builtins.c (fold_builtin_load_exponent): New.

39
gcc/simplify-rtx.c
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@ -2072,6 +2072,33 @@ simplify_binary_operation_1 (enum rtx_code code, enum machine_mode mode,
&& (nonzero_bits (op0, mode) & ~INTVAL (op1)) == 0)
return op1;
/* Canonicalize (X & C1) | C2. */
if (GET_CODE (op0) == AND
&& GET_CODE (trueop1) == CONST_INT
&& GET_CODE (XEXP (op0, 1)) == CONST_INT)
{
HOST_WIDE_INT mask = GET_MODE_MASK (mode);
HOST_WIDE_INT c1 = INTVAL (XEXP (op0, 1));
HOST_WIDE_INT c2 = INTVAL (trueop1);
/* If (C1&C2) == C1, then (X&C1)|C2 becomes X. */
if ((c1 & c2) == c1
&& !side_effects_p (XEXP (op0, 0)))
return trueop1;
/* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
if (((c1|c2) & mask) == mask)
return simplify_gen_binary (IOR, mode, XEXP (op0, 0), op1);
/* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2. */
if (((c1 & ~c2) & mask) != (c1 & mask))
{
tem = simplify_gen_binary (AND, mode, XEXP (op0, 0),
gen_int_mode (c1 & ~c2, mode));
return simplify_gen_binary (IOR, mode, tem, op1);
}
}
/* Convert (A & B) | A to A. */
if (GET_CODE (op0) == AND
&& (rtx_equal_p (XEXP (op0, 0), op1)
@ -2312,6 +2339,18 @@ simplify_binary_operation_1 (enum rtx_code code, enum machine_mode mode,
return simplify_gen_unary (ZERO_EXTEND, mode, tem, imode);
}
/* Canonicalize (A | C1) & C2 as (A & C2) | (C1 & C2). */
if (GET_CODE (op0) == IOR
&& GET_CODE (trueop1) == CONST_INT
&& GET_CODE (XEXP (op0, 1)) == CONST_INT)
{
HOST_WIDE_INT tmp = INTVAL (trueop1) & INTVAL (XEXP (op0, 1));
return simplify_gen_binary (IOR, mode,
simplify_gen_binary (AND, mode,
XEXP (op0, 0), op1),
gen_int_mode (tmp, mode));
}
/* Convert (A ^ B) & A to A & (~B) since the latter is often a single
insn (and may simplify more). */
if (GET_CODE (op0) == XOR

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2007-02-18 Roger Sayle <roger@eyesopen.com>
PR rtl-optimization/28173
* gcc.target/i386/andor-1.c: New test case.
2007-02-18 Kaveh R. Ghazi <ghazi@caip.rutgers.edu>
* gcc.dg/torture/builtin-ldexp-1.c: New.

10
gcc/testsuite/gcc.target/i386/andor-1.c Normal file
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@ -0,0 +1,10 @@
/* { dg-do compile } */
/* { dg-options "-O2" } */
/* { dg-final { scan-assembler-not "andl" } } */
unsigned int foo(unsigned int x)
{
unsigned int t = x & ~1;
return t | 1;
}