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unroll.c (loop_iterations): Don't sign-extend abs_diff; zero-extend it.

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* unroll.c (loop_iterations): Don't sign-extend abs_diff;
zero-extend it.  Make abs_inc unsigned.

From-SVN: r41886
This commit is contained in:
Alexandre Oliva 2001-05-06 19:51:19 +00:00 • committed by Alexandre Oliva
parent 3c04502e2b
commit b8ebd779d5
2 changed files with 20 additions and 7 deletions
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3
gcc/ChangeLog
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@ -1,5 +1,8 @@
2001-05-06 Alexandre Oliva <aoliva@redhat.com>
* unroll.c (loop_iterations): Don't sign-extend abs_diff;
zero-extend it. Make abs_inc unsigned.
* optabs.c (expand_binop): Sign-extend xop0 and xop1 from the
widest mode in narrowing and widening operations.

24
gcc/unroll.c
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@ -3451,7 +3451,8 @@ loop_iterations (loop)
rtx comparison, comparison_value;
rtx iteration_var, initial_value, increment, final_value;
enum rtx_code comparison_code;
HOST_WIDE_INT abs_inc;
HOST_WIDE_INT inc;
unsigned HOST_WIDE_INT abs_inc;
unsigned HOST_WIDE_INT abs_diff;
int off_by_one;
int increment_dir;
@ -3951,18 +3952,27 @@ loop_iterations (loop)
so correct for that. Note that abs_diff and n_iterations are
unsigned, because they can be as large as 2^n - 1. */
abs_inc = INTVAL (increment);
if (abs_inc > 0)
abs_diff = INTVAL (final_value) - INTVAL (initial_value);
else if (abs_inc < 0)
inc = INTVAL (increment);
if (inc > 0)
{
abs_diff = INTVAL (final_value) - INTVAL (initial_value);
abs_inc = inc;
}
else if (inc < 0)
{
abs_diff = INTVAL (initial_value) - INTVAL (final_value);
abs_inc = -abs_inc;
abs_inc = -inc;
}
else
abort ();
abs_diff = trunc_int_for_mode (abs_diff, GET_MODE (iteration_var));
/* Given that iteration_var is going to iterate over its own mode,
not HOST_WIDE_INT, disregard higher bits that might have come
into the picture due to sign extension of initial and final
values. */
abs_diff &= ((unsigned HOST_WIDE_INT)1
<< (GET_MODE_BITSIZE (GET_MODE (iteration_var)) - 1)
<< 1) - 1;
/* For NE tests, make sure that the iteration variable won't miss
the final value. If abs_diff mod abs_incr is not zero, then the