From 71b68cc559b5d30d07e6b507df7cc6d008f56aad Mon Sep 17 00:00:00 2001 From: Andrew Pinski Date: Fri, 30 Jun 2023 19:22:48 -0700 Subject: [PATCH] PR 110487: `(a !=/== CST1 ? CST2 : CST3)` pattern for type safety 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 637d22ccefdc..8543f777a28e 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -4799,24 +4799,16 @@ 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; @@ -4824,7 +4816,7 @@ 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 @@ -4838,7 +4830,7 @@ 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 -- 2.47.2