From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from xry111.site (xry111.site [IPv6:2001:470:683e::1]) by sourceware.org (Postfix) with ESMTPS id B9E3F3858427 for ; Fri, 4 Nov 2022 06:40:43 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org B9E3F3858427 Authentication-Results: sourceware.org; dmarc=pass (p=reject dis=none) header.from=xry111.site Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=xry111.site DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=xry111.site; s=default; t=1667544041; bh=KQqwtuX3W7NYZqSdDh3UfcpSK/Em5ycn1H+bqwZpR/I=; h=From:To:Cc:Subject:Date:From; b=ThG4B/modfY2BPAbecFGYvzh2Phn9He1hY2fjXZNHxYN7fNJQQWjcbVXgrSFukipL cOGlFxU/kAq3+hn0xQ5I8XUxFhc1s7SOJUg70oWTeSBlEjDuez8a6ry7l0+lJpeWs6 GDHSTISJZBePFTQUMCeDDX8DxyLMjvioplnoKWi4= Received: from xry111-x57s1.. (unknown [IPv6:240e:358:11ed:a500:dc73:854d:832e:4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384) server-digest SHA384) (Client did not present a certificate) (Authenticated sender: xry111@xry111.site) by xry111.site (Postfix) with ESMTPSA id 938CF667E5; Fri, 4 Nov 2022 02:40:37 -0400 (EDT) From: Xi Ruoyao To: gcc-patches@gcc.gnu.org Cc: Lulu Cheng , Wang Xuerui , Chenghua Xu , Xi Ruoyao Subject: [PATCH] LoongArch: fix signed overflow in loongarch_emit_int_compare Date: Fri, 4 Nov 2022 14:39:41 +0800 Message-Id: <20221104063942.1594844-1-xry111@xry111.site> X-Mailer: git-send-email 2.38.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-6.5 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FROM_SUSPICIOUS_NTLD,FROM_SUSPICIOUS_NTLD_FP,GIT_PATCH_0,LIKELY_SPAM_FROM,PDS_OTHER_BAD_TLD,SPF_HELO_PASS,SPF_PASS,TXREP 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: Signed overflow is an undefined behavior, so we need to prevent it from happening, instead of "checking" the result. gcc/ChangeLog: * config/loongarch/loongarch.cc (loongarch_emit_int_compare): Avoid signed overflow. --- Bootstrapped and regtested on loongarch64-linux-gnu. OK for trunk? gcc/config/loongarch/loongarch.cc | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/gcc/config/loongarch/loongarch.cc b/gcc/config/loongarch/loongarch.cc index f54c233f90c..032fb1474c7 100644 --- a/gcc/config/loongarch/loongarch.cc +++ b/gcc/config/loongarch/loongarch.cc @@ -4175,13 +4175,14 @@ loongarch_emit_int_compare (enum rtx_code *code, rtx *op0, rtx *op1) HOST_WIDE_INT new_rhs; bool increment = *code == mag_comparisons[i][0]; bool decrement = *code == mag_comparisons[i][1]; - if (!increment && !decrement) + if ((!increment && !decrement) + || (increment && rhs == HOST_WIDE_INT_MAX) + || (decrement && rhs == HOST_WIDE_INT_MIN)) continue; new_rhs = rhs + (increment ? 1 : -1); if (loongarch_integer_cost (new_rhs) - < loongarch_integer_cost (rhs) - && (rhs < 0) == (new_rhs < 0)) + < loongarch_integer_cost (rhs)) { *op1 = GEN_INT (new_rhs); *code = mag_comparisons[i][increment]; -- 2.38.1