OpenE2K
/
gcc
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

re PR rtl-optimization/19001 (Loops with power of two step and variable bounds not unrolled) 

PR rtl-optimization/19001
	* loop-iv.c (iv_number_of_iterations): Record assumptions for loops
	with power of two step to 'infinite' field.

From-SVN: r92361
This commit is contained in:
Zdenek Dvorak 2004-12-18 21:14:24 +01:00 committed by Zdenek Dvorak
parent 00f24ef794
commit 6b9b7b4cf8
2 changed files with 79 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
gcc/ChangeLog
View File

@ -1,3 +1,9 @@
2004-12-18 Zdenek Dvorak <dvorakz@suse.cz>
PR rtl-optimization/19001
* loop-iv.c (iv_number_of_iterations): Record assumptions for loops
with power of two step to 'infinite' field.
2004-12-18 Roger Sayle <roger@eyesopen.com>
* Makefile.in (stor-layout.o): Depend upon gt-stor-layout.h.

89
gcc/loop-iv.c
View File

@ -2017,9 +2017,10 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition,
enum machine_mode mode, comp_mode;
rtx mmin, mmax, mode_mmin, mode_mmax;
unsigned HOST_WIDEST_INT s, size, d, inv;
HOST_WIDEST_INT up, down, inc;
HOST_WIDEST_INT up, down, inc, step_val;
int was_sharp = false;
rtx old_niter;
bool step_is_pow2;
/* The meaning of these assumptions is this:
if !assumptions
@ -2126,10 +2127,26 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition,
if (iv0.step == const0_rtx && iv1.step == const0_rtx)
goto fail;
/* Ignore loops of while (i-- < 10) type. */
if (cond != NE
&& (INTVAL (iv0.step) < 0 || INTVAL (iv1.step) > 0))
goto fail;
if (cond != NE)
{
if (iv0.step == const0_rtx)
step_val = -INTVAL (iv1.step);
else
step_val = INTVAL (iv1.step);
/* Ignore loops of while (i-- < 10) type. */
if (step_val < 0)
goto fail;
step_is_pow2 = !(step_val & (step_val - 1));
}
else
{
/* We do not care about whether the step is power of two in this
case. */
step_is_pow2 = false;
step_val = 0;
}
/* Some more condition normalization. We must record some assumptions
due to overflows. */
@ -2270,8 +2287,7 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition,
/* If the step is a power of two and the final value we have
computed overflows, the cycle is infinite. Otherwise it
is nontrivial to compute the number of iterations. */
s = INTVAL (step);
if ((s & (s - 1)) == 0)
if (step_is_pow2)
desc->infinite = alloc_EXPR_LIST (0, may_not_xform,
desc->infinite);
else
@ -2372,11 +2388,32 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition,
tmp1 = lowpart_subreg (mode, iv1.base, comp_mode);
bound = simplify_gen_binary (MINUS, mode, mode_mmax,
lowpart_subreg (mode, step, comp_mode));
assumption = simplify_gen_relational (cond, SImode, mode,
tmp1, bound);
desc->assumptions =
alloc_EXPR_LIST (0, assumption, desc->assumptions);
lowpart_subreg (mode, step,
comp_mode));
if (step_is_pow2)
{
rtx t0, t1;
/* If s is power of 2, we know that the loop is infinite if
a % s <= b % s and b + s overflows. */
assumption = simplify_gen_relational (reverse_condition (cond),
SImode, mode,
tmp1, bound);
t0 = simplify_gen_binary (UMOD, mode, copy_rtx (tmp0), step);
t1 = simplify_gen_binary (UMOD, mode, copy_rtx (tmp1), step);
tmp = simplify_gen_relational (cond, SImode, mode, t0, t1);
assumption = simplify_gen_binary (AND, SImode, assumption, tmp);
desc->infinite =
alloc_EXPR_LIST (0, assumption, desc->infinite);
}
else
{
assumption = simplify_gen_relational (cond, SImode, mode,
tmp1, bound);
desc->assumptions =
alloc_EXPR_LIST (0, assumption, desc->assumptions);
}
tmp = simplify_gen_binary (PLUS, comp_mode, iv1.base, iv0.step);
tmp = lowpart_subreg (mode, tmp, comp_mode);
@ -2397,10 +2434,30 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition,
bound = simplify_gen_binary (MINUS, mode, mode_mmin,
lowpart_subreg (mode, step, comp_mode));
assumption = simplify_gen_relational (cond, SImode, mode,
bound, tmp0);
desc->assumptions =
alloc_EXPR_LIST (0, assumption, desc->assumptions);
if (step_is_pow2)
{
rtx t0, t1;
/* If s is power of 2, we know that the loop is infinite if
a % s <= b % s and a - s overflows. */
assumption = simplify_gen_relational (reverse_condition (cond),
SImode, mode,
bound, tmp0);
t0 = simplify_gen_binary (UMOD, mode, copy_rtx (tmp0), step);
t1 = simplify_gen_binary (UMOD, mode, copy_rtx (tmp1), step);
tmp = simplify_gen_relational (cond, SImode, mode, t0, t1);
assumption = simplify_gen_binary (AND, SImode, assumption, tmp);
desc->infinite =
alloc_EXPR_LIST (0, assumption, desc->infinite);
}
else
{
assumption = simplify_gen_relational (cond, SImode, mode,
bound, tmp0);
desc->assumptions =
alloc_EXPR_LIST (0, assumption, desc->assumptions);
}
tmp = simplify_gen_binary (PLUS, comp_mode, iv0.base, iv1.step);
tmp = lowpart_subreg (mode, tmp, comp_mode);