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re PR target/39715 ([cond-optab] extra sign extensions on Thumb) 

2009-10-28  Paolo Bonzini  <bonzini@gnu.org>

	PR rtl-optimization/39715
	* combine.c (simplify_comparison): Use extensions to
	widen comparisons.  Try an ANDing first.

testsuite:
2009-10-28  Paolo Bonzini  <bonzini@gnu.org>

	PR rtl-optimization/39715
	* gcc.target/arm/thumb-bitfld1.c: New.

From-SVN: r153651
This commit is contained in:
Paolo Bonzini 2009-10-28 10:27:15 +00:00 committed by Paolo Bonzini
parent 582021baa7
commit 5d49d0ea6c
4 changed files with 60 additions and 21 deletions
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6
gcc/ChangeLog
View File

@ -1,3 +1,9 @@
2009-10-28 Paolo Bonzini <bonzini@gnu.org>
PR rtl-optimization/39715
* combine.c (simplify_comparison): Use extensions to
widen comparisons. Try an ANDing first.
2009-10-28 Paolo Bonzini <bonzini@gnu.org>
PR rtl-optimization/40741

51
gcc/combine.c
View File

@ -11467,6 +11467,22 @@ simplify_comparison (enum rtx_code code, rtx *pop0, rtx *pop1)
{
int zero_extended;
/* If this is a test for negative, we can make an explicit
test of the sign bit. Test this first so we can use
a paradoxical subreg to extend OP0. */
if (op1 == const0_rtx && (code == LT || code == GE)
&& GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT)
{
op0 = simplify_gen_binary (AND, tmode,
gen_lowpart (tmode, op0),
GEN_INT ((HOST_WIDE_INT) 1
<< (GET_MODE_BITSIZE (mode)
- 1)));
code = (code == LT) ? NE : EQ;
break;
}
/* If the only nonzero bits in OP0 and OP1 are those in the
narrower mode and this is an equality or unsigned comparison,
we can use the wider mode. Similarly for sign-extended
@ -11497,27 +11513,20 @@ simplify_comparison (enum rtx_code code, rtx *pop0, rtx *pop1)
XEXP (op0, 0)),
gen_lowpart (tmode,
XEXP (op0, 1)));
op0 = gen_lowpart (tmode, op0);
if (zero_extended && CONST_INT_P (op1))
op1 = GEN_INT (INTVAL (op1) & GET_MODE_MASK (mode));
op1 = gen_lowpart (tmode, op1);
break;
}
/* If this is a test for negative, we can make an explicit
test of the sign bit. */
if (op1 == const0_rtx && (code == LT || code == GE)
&& GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT)
{
op0 = simplify_gen_binary (AND, tmode,
gen_lowpart (tmode, op0),
GEN_INT ((HOST_WIDE_INT) 1
<< (GET_MODE_BITSIZE (mode)
- 1)));
code = (code == LT) ? NE : EQ;
break;
else
{
if (zero_extended)
{
op0 = simplify_gen_unary (ZERO_EXTEND, tmode, op0, mode);
op1 = simplify_gen_unary (ZERO_EXTEND, tmode, op1, mode);
}
else
{
op0 = simplify_gen_unary (SIGN_EXTEND, tmode, op0, mode);
op1 = simplify_gen_unary (SIGN_EXTEND, tmode, op1, mode);
}
break;
}
}
}

5
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,8 @@
2009-10-28 Paolo Bonzini <bonzini@gnu.org>
PR rtl-optimization/39715
* gcc.target/arm/thumb-bitfld1.c: New.
2009-10-28 Paolo Bonzini <bonzini@gnu.org>
PR rtl-optimization/40741

19
gcc/testsuite/gcc.target/arm/thumb-bitfld1.c Normal file
View File

@ -0,0 +1,19 @@
/* { dg-do compile } */
/* { dg-options "-O1 -mthumb -march=armv5t" } */
struct foo
{
unsigned b31 : 1;
unsigned b30 : 1;
unsigned b29 : 1;
unsigned b28 : 1;
unsigned rest : 28;
};
foo(a)
struct foo a;
{
return a.b30;
}
/* { dg-final { scan-assembler-times "lsl" 1 } } */
/* { dg-final { scan-assembler-times "lsr" 1 } } */