Alan Modra <amo...@gmail.com> writes:
> On Thu, Jan 03, 2019 at 07:03:59PM +0000, Richard Sandiford wrote:
>> Richard Sandiford <richard.sandif...@arm.com> writes:
>> > This still seems risky and isn't what the name and function comment
>
> OK, how about this delta from the previous patch to ameliorate the
> maintenance risk?
attr_value_alignment seems clearer, and means that we can handle
things like:
(mult (symbol_ref "...") (const_int 4))
How about the patch below?
Thanks,
Richard
2019-01-04 Richard Sandiford <richard.sandif...@arm.com>
gcc/
* genattrtab.c (or_attr_value): Replace with...
(attr_value_alignment): ...this new function. Handle PLUS,
MINUS and MULT.
(write_length_unit_log): Update accordingly.
Index: gcc/genattrtab.c
===================================================================
--- gcc/genattrtab.c 2019-01-04 12:16:51.000000000 +0000
+++ gcc/genattrtab.c 2019-01-04 12:16:51.322900008 +0000
@@ -268,7 +268,7 @@ static void insert_insn_ent (stru
static void walk_attr_value (rtx);
static int max_attr_value (rtx, int*);
static int min_attr_value (rtx, int*);
-static int or_attr_value (rtx, int*);
+static unsigned int attr_value_alignment (rtx);
static rtx simplify_test_exp (rtx, int, int);
static rtx simplify_test_exp_in_temp (rtx, int, int);
static rtx copy_rtx_unchanging (rtx);
@@ -1568,24 +1568,21 @@ write_length_unit_log (FILE *outf)
struct attr_value *av;
struct insn_ent *ie;
unsigned int length_unit_log, length_or;
- int unknown = 0;
if (length_attr)
{
- length_or = or_attr_value (length_attr->default_val->value, &unknown);
+ length_or = attr_value_alignment (length_attr->default_val->value);
for (av = length_attr->first_value; av; av = av->next)
for (ie = av->first_insn; ie; ie = ie->next)
- length_or |= or_attr_value (av->value, &unknown);
- }
+ length_or |= attr_value_alignment (av->value);
- if (length_attr == NULL || unknown)
- length_unit_log = 0;
- else
- {
length_or = ~length_or;
for (length_unit_log = 0; length_or & 1; length_or >>= 1)
length_unit_log++;
}
+ else
+ length_unit_log = 0;
+
fprintf (outf, "EXPORTED_CONST int length_unit_log = %u;\n",
length_unit_log);
}
@@ -3835,16 +3832,16 @@ min_attr_value (rtx exp, int *unknownp)
return current_min;
}
-/* Given an attribute value, return the result of ORing together all
- CONST_STRING arguments encountered. Set *UNKNOWNP and return -1
- if the numeric value is not known. */
+/* Given an attribute value EXP, return the maximum alignment that all
+ values are known to have. Return 0 if EXP is known to be zero. */
-static int
-or_attr_value (rtx exp, int *unknownp)
+static unsigned int
+attr_value_alignment (rtx exp)
{
- int current_or;
+ unsigned int current_or;
int i;
+ /* When breaking, OR the possible alignment values into CURRENT_OR. */
switch (GET_CODE (exp))
{
case CONST_STRING:
@@ -3852,23 +3849,31 @@ or_attr_value (rtx exp, int *unknownp)
break;
case COND:
- current_or = or_attr_value (XEXP (exp, 1), unknownp);
+ current_or = attr_value_alignment (XEXP (exp, 1));
for (i = 0; i < XVECLEN (exp, 0); i += 2)
- current_or |= or_attr_value (XVECEXP (exp, 0, i + 1), unknownp);
+ current_or |= attr_value_alignment (XVECEXP (exp, 0, i + 1));
break;
case IF_THEN_ELSE:
- current_or = or_attr_value (XEXP (exp, 1), unknownp);
- current_or |= or_attr_value (XEXP (exp, 2), unknownp);
+ current_or = attr_value_alignment (XEXP (exp, 1));
+ current_or |= attr_value_alignment (XEXP (exp, 2));
break;
- default:
- *unknownp = 1;
- current_or = -1;
+ case PLUS:
+ case MINUS:
+ current_or = attr_value_alignment (XEXP (exp, 0));
+ current_or |= attr_value_alignment (XEXP (exp, 1));
break;
+
+ case MULT:
+ return (attr_value_alignment (XEXP (exp, 0))
+ * attr_value_alignment (XEXP (exp, 1)));
+
+ default:
+ return 1;
}
- return current_or;
+ return current_or & -current_or;
}
/* Scan an attribute value, possibly a conditional, and record what actions
