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optabs.c (prepare_cmp_insn): If unbaised and unsigned then bias the comparison routine return.

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gcc/

2006-01-30  Carlos O'Donell  <carlos@codesourcery.com>

	* optabs.c (prepare_cmp_insn): If unbaised and unsigned then bias
	the comparison routine return.

gcc/testsuite/

2006-01-30  Carlos O'Donell  <carlos@codesourcery.com>

	* gcc.dg/unsigned-long-compare.c: New test.

From-SVN: r110409
This commit is contained in:
Carlos O'Donell 2006-01-30 19:58:57 +00:00 committed by Carlos O'Donell
parent b39f98f94d
commit f34312c23c
4 changed files with 48 additions and 9 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
2006-01-30 Carlos O'Donell <carlos@codesourcery.com>
* optabs.c (prepare_cmp_insn): If unbaised and unsigned then bias
the comparison routine return.
2006-01-30 Michael Matz <matz@suse.de>
* global.c (find_reg): Only evict for global regs.

20
gcc/optabs.c
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@ -3711,18 +3711,24 @@ prepare_cmp_insn (rtx *px, rtx *py, enum rtx_code *pcomparison, rtx size,
result = emit_library_call_value (libfunc, NULL_RTX, LCT_CONST_MAKE_BLOCK,
word_mode, 2, x, mode, y, mode);
/* There are two kinds of comparison routines. Biased routines
return 0/1/2, and unbiased routines return -1/0/1. Other parts
of gcc expect that the comparison operation is equivalent
to the modified comparison. For signed comparisons compare the
result against 1 in the biased case, and zero in the unbiased
case. For unsigned comparisons always compare against 1 after
biasing the unbased result by adding 1. This gives us a way to
represent LTU. */
*px = result;
*pmode = word_mode;
if (TARGET_LIB_INT_CMP_BIASED)
/* Integer comparison returns a result that must be compared
against 1, so that even if we do an unsigned compare
afterward, there is still a value that can represent the
result "less than". */
*py = const1_rtx;
else
if (!TARGET_LIB_INT_CMP_BIASED)
{
if (*punsignedp)
*px = plus_constant (result, 1);
else
*py = const0_rtx;
*punsignedp = 1;
}
return;
}

4
gcc/testsuite/ChangeLog
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@ -1,3 +1,7 @@
2006-01-30 Carlos O'Donell <carlos@codesourcery.com>
* gcc.dg/unsigned-long-compare.c: New test.
2006-01-30 Steve Ellcey <sje@cup.hp.com>
PR testsuite/25318

24
gcc/testsuite/gcc.dg/unsigned-long-compare.c Normal file
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@ -0,0 +1,24 @@
/* Copyright (C) 2006 Free Software Foundation, Inc. */
/* Contributed by Carlos O'Donell on 2006-01-30 */
/* Test a division corner case where the expression simplifies
to a comparison, and the optab expansion is wrong. The optab
expansion emits a function whose return is unbiased and needs
adjustment. */
/* Origin: Carlos O'Donell <carlos@codesourcery.com> */
/* { dg-do run { target arm-*-*eabi* } } */
/* { dg-options "" } */
#include <stdlib.h>
#define BIG_CONSTANT 0xFFFFFFFF80000000ULL
int main (void)
{
unsigned long long OneULL = 1ULL;
unsigned long long result;
result = OneULL / BIG_CONSTANT;
if (result)
abort ();
exit (0);
}