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Re: More type narrowing in match.pd
- From: Marc Glisse <marc dot glisse at inria dot fr>
- To: Richard Biener <richard dot guenther at gmail dot com>
- Cc: Jeff Law <law at redhat dot com>, GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Thu, 30 Apr 2015 12:53:31 +0200 (CEST)
- Subject: Re: More type narrowing in match.pd
- Authentication-results: sourceware.org; auth=none
- References: <5541A704 dot 3070502 at redhat dot com> <CAFiYyc2u-zSP_DErk73ZEUXOgLfeT3NGa+fiA6uu5JxWFZjurg at mail dot gmail dot com>
- Reply-to: gcc-patches at gcc dot gnu dot org
On Thu, 30 Apr 2015, Richard Biener wrote:
I have in my local dev tree (so completely untested...)
@@ -1040,31 +1052,22 @@ (define_operator_list CBRT BUILT_IN_CBRT
operation and convert the result to the desired type. */
(for op (plus minus)
(simplify
- (convert (op (convert@2 @0) (convert@3 @1)))
+ (convert (op:c@4 (convert@2 @0) (convert?@3 @1)))
I believe the :c here requires extra code further down, so we don't turn
a-b into b-a.
(if (INTEGRAL_TYPE_P (type)
- /* We check for type compatibility between @0 and @1 below,
- so there's no need to check that @1/@3 are integral types. */
&& INTEGRAL_TYPE_P (TREE_TYPE (@0))
- && INTEGRAL_TYPE_P (TREE_TYPE (@2))
+ && INTEGRAL_TYPE_P (TREE_TYPE (@4))
/* The precision of the type of each operand must match the
precision of the mode of each operand, similarly for the
result. */
&& (TYPE_PRECISION (TREE_TYPE (@0))
== GET_MODE_PRECISION (TYPE_MODE (TREE_TYPE (@0))))
- && (TYPE_PRECISION (TREE_TYPE (@1))
- == GET_MODE_PRECISION (TYPE_MODE (TREE_TYPE (@1))))
- && TYPE_PRECISION (type) == GET_MODE_PRECISION (TYPE_MODE (type))
/* The inner conversion must be a widening conversion. */
&& TYPE_PRECISION (TREE_TYPE (@2)) > TYPE_PRECISION (TREE_TYPE (@0))
- && ((GENERIC
- && (TYPE_MAIN_VARIANT (TREE_TYPE (@0))
- == TYPE_MAIN_VARIANT (TREE_TYPE (@1)))
- && (TYPE_MAIN_VARIANT (TREE_TYPE (@0))
- == TYPE_MAIN_VARIANT (type)))
- || (GIMPLE
- && types_compatible_p (TREE_TYPE (@0), TREE_TYPE (@1))
- && types_compatible_p (TREE_TYPE (@0), type))))
+ /* The final precision should match that of operand @0. */
+ && TYPE_PRECISION (type) == TYPE_PRECISION (TREE_TYPE (@0))
+ /* Make sure the wide operation is dead after the transform. */
+ && (TREE_CODE (@4) != SSA_NAME || has_single_use (@4)))
(if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (@0)))
- (convert (op @0 @1)))
+ (convert (op @0 (convert @1))))
(with { tree utype = unsigned_type_for (TREE_TYPE (@0)); }
(convert (op (convert:utype @0) (convert:utype @1)))))))
--
Marc Glisse