This patch tree-vrp handling and optimization for ZEXT_EXPR.
gcc/ChangeLog:
2015-09-07 Kugan Vivekanandarajah <kug...@linaro.org>
* tree-vrp.c (extract_range_from_binary_expr_1): Handle SEXT_EXPR.
(simplify_bit_ops_using_ranges): Likewise.
(simplify_stmt_using_ranges): Likewise.
>From 7143e0575f309f70d838edf436b555fb93a6c4bb Mon Sep 17 00:00:00 2001
From: Kugan Vivekanandarajah <kugan.vivekanandara...@linaro.org>
Date: Mon, 17 Aug 2015 13:45:52 +1000
Subject: [PATCH 3/8] Optimize ZEXT_EXPR with tree-vrp
---
gcc/tree-vrp.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 75 insertions(+)
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index 21fbed0..d579b49 100644
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -2327,6 +2327,7 @@ extract_range_from_binary_expr_1 (value_range_t *vr,
&& code != LSHIFT_EXPR
&& code != MIN_EXPR
&& code != MAX_EXPR
+ && code != SEXT_EXPR
&& code != BIT_AND_EXPR
&& code != BIT_IOR_EXPR
&& code != BIT_XOR_EXPR)
@@ -2887,6 +2888,55 @@ extract_range_from_binary_expr_1 (value_range_t *vr,
extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1);
return;
}
+ else if (code == SEXT_EXPR)
+ {
+ gcc_assert (range_int_cst_p (&vr1));
+ unsigned int prec = tree_to_uhwi (vr1.min);
+ type = vr0.type;
+ wide_int tmin, tmax;
+ wide_int type_min, type_max;
+ wide_int may_be_nonzero, must_be_nonzero;
+
+ gcc_assert (!TYPE_UNSIGNED (expr_type));
+ type_min = wi::shwi (1 << (prec - 1),
+ TYPE_PRECISION (TREE_TYPE (vr0.min)));
+ type_max = wi::shwi (((1 << (prec - 1)) - 1),
+ TYPE_PRECISION (TREE_TYPE (vr0.max)));
+ if (zero_nonzero_bits_from_vr (expr_type, &vr0,
+ &may_be_nonzero,
+ &must_be_nonzero))
+ {
+ HOST_WIDE_INT int_may_be_nonzero = may_be_nonzero.to_uhwi ();
+ HOST_WIDE_INT int_must_be_nonzero = must_be_nonzero.to_uhwi ();
+
+ if (int_must_be_nonzero & (1 << (prec - 1)))
+ {
+ /* If to-be-extended sign bit is one. */
+ tmin = type_min;
+ tmax = may_be_nonzero;
+ }
+ else if ((int_may_be_nonzero & (1 << (prec - 1))) == 0)
+ {
+ /* If to-be-extended sign bit is zero. */
+ tmin = must_be_nonzero;
+ tmax = may_be_nonzero;
+ }
+ else
+ {
+ tmin = type_min;
+ tmax = type_max;
+ }
+ }
+ else
+ {
+ tmin = type_min;
+ tmax = type_max;
+ }
+ tmin = wi::sext (tmin, prec - 1);
+ tmax = wi::sext (tmax, prec - 1);
+ min = wide_int_to_tree (expr_type, tmin);
+ max = wide_int_to_tree (expr_type, tmax);
+ }
else if (code == RSHIFT_EXPR
|| code == LSHIFT_EXPR)
{
@@ -9254,6 +9304,30 @@ simplify_bit_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
break;
}
break;
+ case SEXT_EXPR:
+ {
+ gcc_assert (is_gimple_min_invariant (op1));
+ unsigned int prec = tree_to_uhwi (op1);
+ wide_int mask;
+ HOST_WIDE_INT may_be_nonzero = may_be_nonzero0.to_uhwi ();
+ HOST_WIDE_INT must_be_nonzero = must_be_nonzero0.to_uhwi ();
+ mask = wi::shwi (((1 << (prec - 1)) - 1),
+ TYPE_PRECISION (TREE_TYPE (vr0.max)));
+ mask = wi::bit_not (mask);
+ if (must_be_nonzero & (1 << (prec - 1)))
+ {
+ /* If to-be-extended sign bit is one. */
+ if (wi::bit_and (must_be_nonzero0, mask) == mask)
+ op = op0;
+ }
+ else if ((may_be_nonzero & (1 << (prec - 1))) == 0)
+ {
+ /* If to-be-extended sign bit is zero. */
+ if (wi::bit_and (may_be_nonzero0, mask) == 0)
+ op = op0;
+ }
+ }
+ break;
default:
gcc_unreachable ();
}
@@ -9955,6 +10029,7 @@ simplify_stmt_using_ranges (gimple_stmt_iterator *gsi)
case BIT_AND_EXPR:
case BIT_IOR_EXPR:
+ case SEXT_EXPR:
/* Optimize away BIT_AND_EXPR and BIT_IOR_EXPR
if all the bits being cleared are already cleared or
all the bits being set are already set. */
--
1.9.1
