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arm.c (arm_canonicalize_comparison): Add case to canonicalize left operand from ZERO_EXTEND to AND.

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2011-07-20  Chung-Lin Tang  <cltang@codesourcery.com>

	* config/arm/arm.c (arm_canonicalize_comparison): Add case to
	canonicalize left operand from ZERO_EXTEND to AND.

	testsuite/
	* gcc.target/arm/combine-movs.c: New.
	* gcc.target/arm/unsigned-extend-2.c: New.

From-SVN: r176495
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Chung-Lin Tang 2011-07-20 06:21:36 +00:00 committed by Chung-Lin Tang
parent e7b6c2cb75
commit b0e43da8fb
5 changed files with 53 additions and 0 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
2011-07-20 Chung-Lin Tang <cltang@codesourcery.com>
* config/arm/arm.c (arm_canonicalize_comparison): Add case to
canonicalize left operand from ZERO_EXTEND to AND.
2011-07-20 Anatoly Sokolov <aesok@post.ru>
* target.def (class_max_nregs): New hook.

13
gcc/config/arm/arm.c
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@ -3172,6 +3172,19 @@ arm_canonicalize_comparison (enum rtx_code code, rtx *op0, rtx *op1)
return code;
}
/* If *op0 is (zero_extend:SI (subreg:QI (reg:SI) 0)) and comparing
with const0_rtx, change it to (and:SI (reg:SI) (const_int 255)),
to facilitate possible combining with a cmp into 'ands'. */
if (mode == SImode
&& GET_CODE (*op0) == ZERO_EXTEND
&& GET_CODE (XEXP (*op0, 0)) == SUBREG
&& GET_MODE (XEXP (*op0, 0)) == QImode
&& GET_MODE (SUBREG_REG (XEXP (*op0, 0))) == SImode
&& subreg_lowpart_p (XEXP (*op0, 0))
&& *op1 == const0_rtx)
*op0 = gen_rtx_AND (SImode, SUBREG_REG (XEXP (*op0, 0)),
GEN_INT (255));
/* Comparisons smaller than DImode. Only adjust comparisons against
an out-of-range constant. */
if (GET_CODE (*op1) != CONST_INT

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2011-07-20 Chung-Lin Tang <cltang@codesourcery.com>
* gcc.target/arm/combine-movs.c: New.
* gcc.target/arm/unsigned-extend-2.c: New.
2011-07-19 Jason Merrill <jason@redhat.com>
PR c++/49785

12
gcc/testsuite/gcc.target/arm/combine-movs.c Normal file
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@ -0,0 +1,12 @@
/* { dg-do compile } */
/* { dg-skip-if "" { arm_thumb1 } } */
/* { dg-options "-O" } */
void foo (unsigned long r[], unsigned int d)
{
int i, n = d / 32;
for (i = 0; i < n; ++i)
r[i] = 0;
}
/* { dg-final { scan-assembler "movs\tr\[0-9\]" } } */

18
gcc/testsuite/gcc.target/arm/unsigned-extend-2.c Normal file
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@ -0,0 +1,18 @@
/* { dg-do compile } */
/* { dg-require-effective-target arm_thumb2_ok } */
/* { dg-options "-O" } */
unsigned short foo (unsigned short x)
{
unsigned char i = 0;
for (i = 0; i < 8; i++)
{
x >>= 1;
x &= 0x7fff;
}
return x;
}
/* { dg-final { scan-assembler "ands" } } */
/* { dg-final { scan-assembler-not "uxtb" } } */
/* { dg-final { scan-assembler-not "cmp" } } */