The problem here is we might produce some values out of the type's
min/max (and/or valid values, e.g. signed booleans). The fix is to
use an integer type which has the same precision and signedness
as the original type.
Note two_value_replacement in phiopt had the same issue in previous
versions; though I don't know if a problem will show up there.
OK? Bootstrapped and tested on x86_64-linux-gnu.
gcc/ChangeLog:
PR tree-optimization/110487
* match.pd (a !=/== CST1 ? CST2 : CST3): Always
build a nonstandard integer and use that.
---
gcc/match.pd | 24 ++++++++----------------
1 file changed, 8 insertions(+), 16 deletions(-)
diff --git a/gcc/match.pd b/gcc/match.pd
index a0d114f6a16..9748ad8466e 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -4797,24 +4797,16 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
tree type1;
if ((eqne == EQ_EXPR) ^ (wi::to_wide (@1) == min))
std::swap (arg0, arg1);
- if (TYPE_PRECISION (TREE_TYPE (@0)) == TYPE_PRECISION (type))
- {
- /* Avoid performing the arithmetics in bool type which has different
- semantics, otherwise prefer unsigned types from the two with
- the same precision. */
- if (TREE_CODE (TREE_TYPE (arg0)) == BOOLEAN_TYPE
- || !TYPE_UNSIGNED (type))
- type1 = TREE_TYPE (@0);
- else
- type1 = TREE_TYPE (arg0);
- }
- else if (TYPE_PRECISION (TREE_TYPE (@0)) > TYPE_PRECISION (type))
+ if (TYPE_PRECISION (TREE_TYPE (@0)) > TYPE_PRECISION (type))
type1 = TREE_TYPE (@0);
else
type1 = type;
- min = wide_int::from (min, TYPE_PRECISION (type1),
+ auto prec = TYPE_PRECISION (type1);
+ auto unsign = TYPE_UNSIGNED (type1);
+ type1 = build_nonstandard_integer_type (prec, unsign);
+ min = wide_int::from (min, prec,
TYPE_SIGN (TREE_TYPE (@0)));
- wide_int a = wide_int::from (wi::to_wide (arg0), TYPE_PRECISION (type1),
+ wide_int a = wide_int::from (wi::to_wide (arg0), prec,
TYPE_SIGN (type));
enum tree_code code;
wi::overflow_type ovf;
@@ -4822,7 +4814,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
{
code = PLUS_EXPR;
a -= min;
- if (!TYPE_UNSIGNED (type1))
+ if (!unsign)
{
/* lhs is known to be in range [min, min+1] and we want to add a
to it. Check if that operation can overflow for those 2
values
@@ -4836,7 +4828,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
{
code = MINUS_EXPR;
a += min;
- if (!TYPE_UNSIGNED (type1))
+ if (!unsign)
{
/* lhs is known to be in range [min, min+1] and we want to
subtract
it from a. Check if that operation can overflow for those 2
--
2.31.1
