From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by sourceware.org (Postfix) with ESMTPS id 7252A385702B for ; Thu, 27 Jul 2023 13:07:59 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 7252A385702B Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=suse.de Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=suse.de Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id 830611F86C; Thu, 27 Jul 2023 13:07:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1690463278; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=q+SoySliuOP5DhP4O42R2n58VR6IfJl2fMG0jiAQA+8=; b=ReoEDMeVT6uredM2oIZvxEjBzgzN8KMTDy8Sd9OUJsOtTahtvB+Ia9ECRrjSrr+g6XNkRT qsq0b3jK8Xm02bvLK5GYBJSb3JGMr+mL+N1BKYhoOAN0mrN6zHSbQzAWfy5pt8G9ZzFXMf /mSBKcFuw24RakeMfN4ki5AqPJo9N/E= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1690463278; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=q+SoySliuOP5DhP4O42R2n58VR6IfJl2fMG0jiAQA+8=; b=mAQKFcu9ZcgqYW4zAn2lS+40QpsvD+7Oc43XNalNaza8ixxoPwO9edPI7eVuFcSQlBEWUX P9mQzB3bcvjTDdAA== Received: from wotan.suse.de (wotan.suse.de [10.160.0.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 760A52C142; Thu, 27 Jul 2023 13:07:58 +0000 (UTC) Date: Thu, 27 Jul 2023 13:07:58 +0000 (UTC) From: Richard Biener To: Jakub Jelinek cc: gcc-patches@gcc.gnu.org Subject: Re: [PATCH] tree-optimization/91838 - fix FAIL of g++.dg/opt/pr91838.C In-Reply-To: Message-ID: References: <81140.123072708005901359@us-mta-160.us.mimecast.lan> User-Agent: Alpine 2.22 (LSU 394 2020-01-19) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Spam-Status: No, score=-11.0 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,SPF_HELO_NONE,SPF_PASS,TXREP,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On Thu, 27 Jul 2023, Jakub Jelinek wrote: > On Thu, Jul 27, 2023 at 12:00:56PM +0000, Richard Biener wrote: > > The following fixes the lack of simplification of a vector shift > > by an out-of-bounds shift value. For scalars this is done both > > by CCP and VRP but vectors are not handled there. This results > > in PR91838 differences in outcome dependent on whether a vector > > shift ISA is available and thus vector lowering does or does not > > expose scalar shifts here. > > > > The following adds a match.pd pattern to catch uniform out-of-bound > > shifts, simplifying them to zero when not sanitizing shift amounts. > > > > Bootstrapped and tested on x86_64-unknown-linux-gnu. > > > > OK? > > > > Thanks, > > Richard. > > > > PR tree-optimization/91838 > > * match.pd (([rl]shift @0 out-of-bounds) -> zero): New pattern. > > The !(flag_sanitize & SANITIZE_SHIFT_EXPONENT) > should be !sanitize_flags_p (SANITIZE_SHIFT_EXPONENT) > or maybe even > GIMPLE || !sanitize_flags_p (SANITIZE_SHIFT_EXPONENT) > because the shift ubsan instrumentation is done on GENERIC, so it can be > optimized on GIMPLE even with ubsan. > > Otherwise LGTM. So like the following, will push after re-testing succeeded. Thanks, Richard. >From c6d348acdc2143fc4c2849e33075a3975fe29b26 Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Thu, 27 Jul 2023 13:08:32 +0200 Subject: [PATCH] tree-optimization/91838 - fix FAIL of g++.dg/opt/pr91838.C To: gcc-patches@gcc.gnu.org The following fixes the lack of simplification of a vector shift by an out-of-bounds shift value. For scalars this is done both by CCP and VRP but vectors are not handled there. This results in PR91838 differences in outcome dependent on whether a vector shift ISA is available and thus vector lowering does or does not expose scalar shifts here. The following adds a match.pd pattern to catch uniform out-of-bound shifts, simplifying them to zero when not sanitizing shift amounts. PR tree-optimization/91838 * gimple-match-head.cc: Include attribs.h and asan.h. * generic-match-head.cc: Likewise. * match.pd (([rl]shift @0 out-of-bounds) -> zero): New pattern. --- gcc/generic-match-head.cc | 2 ++ gcc/gimple-match-head.cc | 2 ++ gcc/match.pd | 10 ++++++++++ 3 files changed, 14 insertions(+) diff --git a/gcc/generic-match-head.cc b/gcc/generic-match-head.cc index b4b5bc88f4b..a71c0727b0b 100644 --- a/gcc/generic-match-head.cc +++ b/gcc/generic-match-head.cc @@ -41,6 +41,8 @@ along with GCC; see the file COPYING3. If not see #include "tree-eh.h" #include "langhooks.h" #include "tree-pass.h" +#include "attribs.h" +#include "asan.h" /* Routine to determine if the types T1 and T2 are effectively the same for GENERIC. If T1 or T2 is not a type, the test diff --git a/gcc/gimple-match-head.cc b/gcc/gimple-match-head.cc index d795066e53e..5d6d26d009b 100644 --- a/gcc/gimple-match-head.cc +++ b/gcc/gimple-match-head.cc @@ -47,6 +47,8 @@ along with GCC; see the file COPYING3. If not see #include "tm.h" #include "gimple-range.h" #include "langhooks.h" +#include "attribs.h" +#include "asan.h" tree do_valueize (tree, tree (*)(tree), bool &); tree do_valueize (tree (*)(tree), tree); diff --git a/gcc/match.pd b/gcc/match.pd index a443dc48634..fcb1a735507 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -1059,6 +1059,16 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) && tree_nop_conversion_p (type, TREE_TYPE (@1))) (lshift @0 @2))) +/* Shifts by precision or greater result in zero. */ +(for shift (lshift rshift) + (simplify + (shift @0 uniform_integer_cst_p@1) + (if ((GIMPLE || !sanitize_flags_p (SANITIZE_SHIFT_EXPONENT)) + /* Use a signed compare to leave negative shift counts alone. */ + && wi::ges_p (wi::to_wide (uniform_integer_cst_p (@1)), + element_precision (type))) + { build_zero_cst (type); }))) + /* Shifts by constants distribute over several binary operations, hence (X << C) + (Y << C) can be simplified to (X + Y) << C. */ (for op (plus minus) -- 2.35.3 k