From 55738d8d96bb4f39a72cf5e3739d35b39fc2146a Mon Sep 17 00:00:00 2001
From: Andrew MacLeod <amacleod@redhat.com>
Date: Tue, 20 Sep 2022 18:19:30 -0400
Subject: [PATCH 12/17] Convert CFN_CTZ builtins to range-ops.
* gimple-range-fold.cc (range_of_builtin_int_call): Remove case
for CFN_CTZ.
* gimple-range-op.cc (class cfn_ctz): New.
(gimple_range_op_handler::maybe_builtin_call): Set arguments.
---
gcc/gimple-range-fold.cc | 61 +------------------------------
gcc/gimple-range-op.cc | 79 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 80 insertions(+), 60 deletions(-)
@@ -917,7 +917,7 @@ fold_using_range::range_of_builtin_int_call (irange &r, gcall *call,
tree type = gimple_range_type (call);
tree arg;
- int mini, maxi, zerov = 0, prec;
+ int prec;
scalar_int_mode mode;
switch (func)
@@ -926,65 +926,6 @@ fold_using_range::range_of_builtin_int_call (irange &r, gcall *call,
r.set (build_zero_cst (type), build_one_cst (type));
return true;
- CASE_CFN_CTZ:
- // __builtin_ctz* return [0, prec-1], except for when the
- // argument is 0, but that is undefined behavior.
- //
- // For __builtin_ctz* consider argument of 0 always undefined
- // behavior, for internal fns depending on CTZ_DEFINED_VALUE_AT_ZERO.
- arg = gimple_call_arg (call, 0);
- prec = TYPE_PRECISION (TREE_TYPE (arg));
- mini = 0;
- maxi = prec - 1;
- mode = SCALAR_INT_TYPE_MODE (TREE_TYPE (arg));
- if (gimple_call_internal_p (call))
- {
- if (optab_handler (ctz_optab, mode) != CODE_FOR_nothing
- && CTZ_DEFINED_VALUE_AT_ZERO (mode, zerov) == 2)
- {
- // Handle only the two common values.
- if (zerov == -1)
- mini = -1;
- else if (zerov == prec)
- maxi = prec;
- else
- // Magic value to give up, unless we can prove arg is non-zero.
- mini = -2;
- }
- }
- src.get_operand (r, arg);
- if (!r.undefined_p ())
- {
- // If arg is non-zero, then use [0, prec - 1].
- if (!range_includes_zero_p (&r))
- {
- mini = 0;
- maxi = prec - 1;
- }
- // If some high bits are known to be zero, we can decrease
- // the maximum.
- wide_int max = r.upper_bound ();
- if (max == 0)
- {
- // Argument is [0, 0]. If CTZ_DEFINED_VALUE_AT_ZERO
- // is 2 with value -1 or prec, return [-1, -1] or [prec, prec].
- // Otherwise ignore the range.
- if (mini == -1)
- maxi = -1;
- else if (maxi == prec)
- mini = prec;
- }
- // If value at zero is prec and 0 is in the range, we can't lower
- // the upper bound. We could create two separate ranges though,
- // [0,floor_log2(max)][prec,prec] though.
- else if (maxi != prec)
- maxi = wi::floor_log2 (max);
- }
- if (mini == -2)
- break;
- r.set (build_int_cst (type, mini), build_int_cst (type, maxi));
- return true;
-
CASE_CFN_CLRSB:
arg = gimple_call_arg (call, 0);
prec = TYPE_PRECISION (TREE_TYPE (arg));
@@ -489,6 +489,76 @@ cfn_clz::fold_range (irange &r, tree type, const irange &lh,
return true;
}
+// Implement range operator for CFN_BUILT_IN_CTZ
+class cfn_ctz : public range_operator
+{
+public:
+ cfn_ctz (bool internal) { m_gimple_call_internal_p = internal; }
+ using range_operator::fold_range;
+ virtual bool fold_range (irange &r, tree type, const irange &lh,
+ const irange &, relation_kind) const;
+private:
+ bool m_gimple_call_internal_p;
+} op_cfn_ctz (false), op_cfn_ctz_internal (true);
+
+bool
+cfn_ctz::fold_range (irange &r, tree type, const irange &lh,
+ const irange &, relation_kind) const
+{
+ if (lh.undefined_p ())
+ return false;
+ int prec = TYPE_PRECISION (lh.type ());
+ int mini = 0;
+ int maxi = prec - 1;
+ int zerov = 0;
+ scalar_int_mode mode = SCALAR_INT_TYPE_MODE (lh.type ());
+
+ if (m_gimple_call_internal_p)
+ {
+ if (optab_handler (ctz_optab, mode) != CODE_FOR_nothing
+ && CTZ_DEFINED_VALUE_AT_ZERO (mode, zerov) == 2)
+ {
+ // Handle only the two common values.
+ if (zerov == -1)
+ mini = -1;
+ else if (zerov == prec)
+ maxi = prec;
+ else
+ // Magic value to give up, unless we can prove arg is non-zero.
+ mini = -2;
+ }
+ }
+ // If arg is non-zero, then use [0, prec - 1].
+ if (!range_includes_zero_p (&lh))
+ {
+ mini = 0;
+ maxi = prec - 1;
+ }
+ // If some high bits are known to be zero, we can decrease
+ // the maximum.
+ wide_int max = lh.upper_bound ();
+ if (max == 0)
+ {
+ // Argument is [0, 0]. If CTZ_DEFINED_VALUE_AT_ZERO
+ // is 2 with value -1 or prec, return [-1, -1] or [prec, prec].
+ // Otherwise ignore the range.
+ if (mini == -1)
+ maxi = -1;
+ else if (maxi == prec)
+ mini = prec;
+ }
+ // If value at zero is prec and 0 is in the range, we can't lower
+ // the upper bound. We could create two separate ranges though,
+ // [0,floor_log2(max)][prec,prec] though.
+ else if (maxi != prec)
+ maxi = wi::floor_log2 (max);
+
+ if (mini == -2)
+ return false;
+ r.set (build_int_cst (type, mini), build_int_cst (type, maxi));
+ return true;
+}
+
// Set up a gimple_range_op_handler for any built in function which can be
// supported via range-ops.
@@ -553,6 +623,15 @@ gimple_range_op_handler::maybe_builtin_call ()
m_int = &op_cfn_clz;
break;
+ CASE_CFN_CTZ:
+ m_op1 = gimple_call_arg (call, 0);
+ m_valid = true;
+ if (gimple_call_internal_p (call))
+ m_int = &op_cfn_ctz_internal;
+ else
+ m_int = &op_cfn_ctz;
+ break;
+
default:
break;
}
--
2.37.3