From 4d9f13e4ea0068d4912b430f9f6a22cf5ca18211 Mon Sep 17 00:00:00 2001
From: nemet <nemet@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Sun, 24 Sep 2006 19:03:57 +0000
Subject: [PATCH] * tree-ssa-loop-ivopts.c (aff_combination_convert,
determine_common_wider_type): New functions. (get_computation_aff): Use
them to simplify arithmetic between UBASE and CBASE if they are shortened
from the same type.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@117182 138bc75d-0d04-0410-961f-82ee72b054a4
---
gcc/ChangeLog | 8 +++
gcc/tree-ssa-loop-ivopts.c | 105 ++++++++++++++++++++++++++++++++++---
2 files changed, 105 insertions(+), 8 deletions(-)
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 66332b1314ad..245b081ee9f7 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2006-09-24 Zdenek Dvorak <dvorakz@suse.cz>
+ Adam Nemet <anemet@caviumnetworks.com>
+
+ * tree-ssa-loop-ivopts.c (aff_combination_convert,
+ determine_common_wider_type): New functions.
+ (get_computation_aff): Use them to simplify arithmetic between
+ UBASE and CBASE if they are shortened from the same type.
+
2006-09-24 Kazu Hirata <kazu@codesourcery.com>
PR target/28911
diff --git a/gcc/tree-ssa-loop-ivopts.c b/gcc/tree-ssa-loop-ivopts.c
index ae1905d05ded..6029923ae26a 100644
--- a/gcc/tree-ssa-loop-ivopts.c
+++ b/gcc/tree-ssa-loop-ivopts.c
@@ -2762,6 +2762,37 @@ aff_combination_add (struct affine_tree_combination *comb1,
aff_combination_add_elt (comb1, comb2->rest, 1);
}
+/* Convert COMB to TYPE. */
+
+static void
+aff_combination_convert (tree type, struct affine_tree_combination *comb)
+{
+ unsigned prec = TYPE_PRECISION (type);
+ unsigned i;
+
+ /* If the precision of both types is the same, it suffices to change the type
+ of the whole combination -- the elements are allowed to have another type
+ equivalent wrto STRIP_NOPS. */
+ if (prec == TYPE_PRECISION (comb->type))
+ {
+ comb->type = type;
+ return;
+ }
+
+ comb->mask = (((unsigned HOST_WIDE_INT) 2 << (prec - 1)) - 1);
+ comb->offset = comb->offset & comb->mask;
+
+ /* The type of the elements can be different from comb->type only as
+ much as what STRIP_NOPS would remove. We can just directly cast
+ to TYPE. */
+ for (i = 0; i < comb->n; i++)
+ comb->elts[i] = fold_convert (type, comb->elts[i]);
+ if (comb->rest)
+ comb->rest = fold_convert (type, comb->rest);
+
+ comb->type = type;
+}
+
/* Splits EXPR into an affine combination of parts. */
static void
@@ -2951,6 +2982,44 @@ fold_affine_expr (tree expr)
return aff_combination_to_tree (&comb);
}
+/* If A is (TYPE) BA and B is (TYPE) BB, and the types of BA and BB have the
+ same precision that is at least as wide as the precision of TYPE, stores
+ BA to A and BB to B, and returns the type of BA. Otherwise, returns the
+ type of A and B. */
+
+static tree
+determine_common_wider_type (tree *a, tree *b)
+{
+ tree wider_type = NULL;
+ tree suba, subb;
+ tree atype = TREE_TYPE (*a);
+
+ if ((TREE_CODE (*a) == NOP_EXPR
+ || TREE_CODE (*a) == CONVERT_EXPR))
+ {
+ suba = TREE_OPERAND (*a, 0);
+ wider_type = TREE_TYPE (suba);
+ if (TYPE_PRECISION (wider_type) < TYPE_PRECISION (atype))
+ return atype;
+ }
+ else
+ return atype;
+
+ if ((TREE_CODE (*b) == NOP_EXPR
+ || TREE_CODE (*b) == CONVERT_EXPR))
+ {
+ subb = TREE_OPERAND (*b, 0);
+ if (TYPE_PRECISION (wider_type) != TYPE_PRECISION (TREE_TYPE (subb)))
+ return atype;
+ }
+ else
+ return atype;
+
+ *a = suba;
+ *b = subb;
+ return wider_type;
+}
+
/* Determines the expression by that USE is expressed from induction variable
CAND at statement AT in LOOP. The expression is stored in a decomposed
form into AFF. Returns false if USE cannot be expressed using CAND. */
@@ -2965,6 +3034,7 @@ get_computation_aff (struct loop *loop,
tree cbase = cand->iv->base;
tree cstep = cand->iv->step;
tree utype = TREE_TYPE (ubase), ctype = TREE_TYPE (cbase);
+ tree common_type;
tree uutype;
tree expr, delta;
tree ratio;
@@ -3040,9 +3110,20 @@ get_computation_aff (struct loop *loop,
ratioi = 0;
}
+ /* In case both UBASE and CBASE are shortened to UUTYPE from some common
+ type, we achieve better folding by computing their difference in this
+ wider type, and cast the result to UUTYPE. We do not need to worry about
+ overflows, as all the arithmetics will in the end be performed in UUTYPE
+ anyway. */
+ common_type = determine_common_wider_type (&ubase, &cbase);
+
/* We may need to shift the value if we are after the increment. */
if (stmt_after_increment (loop, cand, at))
- cbase = fold_build2 (PLUS_EXPR, uutype, cbase, cstep);
+ {
+ if (uutype != common_type)
+ cstep = fold_convert (common_type, cstep);
+ cbase = fold_build2 (PLUS_EXPR, common_type, cbase, cstep);
+ }
/* use = ubase - ratio * cbase + ratio * var.
@@ -3052,7 +3133,7 @@ get_computation_aff (struct loop *loop,
happen, fold is able to apply the distributive law to obtain this form
anyway. */
- if (TYPE_PRECISION (uutype) > HOST_BITS_PER_WIDE_INT)
+ if (TYPE_PRECISION (common_type) > HOST_BITS_PER_WIDE_INT)
{
/* Let's compute in trees and just return the result in AFF. This case
should not be very common, and fold itself is not that bad either,
@@ -3060,18 +3141,24 @@ get_computation_aff (struct loop *loop,
is not that urgent. */
if (ratioi == 1)
{
- delta = fold_build2 (MINUS_EXPR, uutype, ubase, cbase);
+ delta = fold_build2 (MINUS_EXPR, common_type, ubase, cbase);
+ if (uutype != common_type)
+ delta = fold_convert (uutype, delta);
expr = fold_build2 (PLUS_EXPR, uutype, expr, delta);
}
else if (ratioi == -1)
{
- delta = fold_build2 (PLUS_EXPR, uutype, ubase, cbase);
+ delta = fold_build2 (PLUS_EXPR, common_type, ubase, cbase);
+ if (uutype != common_type)
+ delta = fold_convert (uutype, delta);
expr = fold_build2 (MINUS_EXPR, uutype, delta, expr);
}
else
{
- delta = fold_build2 (MULT_EXPR, uutype, cbase, ratio);
- delta = fold_build2 (MINUS_EXPR, uutype, ubase, delta);
+ delta = fold_build2 (MULT_EXPR, common_type, cbase, ratio);
+ delta = fold_build2 (MINUS_EXPR, common_type, ubase, delta);
+ if (uutype != common_type)
+ delta = fold_convert (uutype, delta);
expr = fold_build2 (MULT_EXPR, uutype, ratio, expr);
expr = fold_build2 (PLUS_EXPR, uutype, delta, expr);
}
@@ -3088,12 +3175,14 @@ get_computation_aff (struct loop *loop,
possible to compute ratioi. */
gcc_assert (ratioi);
- tree_to_aff_combination (ubase, uutype, aff);
- tree_to_aff_combination (cbase, uutype, &cbase_aff);
+ tree_to_aff_combination (ubase, common_type, aff);
+ tree_to_aff_combination (cbase, common_type, &cbase_aff);
tree_to_aff_combination (expr, uutype, &expr_aff);
aff_combination_scale (&cbase_aff, -ratioi);
aff_combination_scale (&expr_aff, ratioi);
aff_combination_add (aff, &cbase_aff);
+ if (common_type != uutype)
+ aff_combination_convert (uutype, aff);
aff_combination_add (aff, &expr_aff);
return true;
--
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