From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by sourceware.org (Postfix) with ESMTPS id 54ED03858C2D for ; Tue, 25 Apr 2023 13:08:37 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 54ED03858C2D 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 imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 7EA5B2193C; Tue, 25 Apr 2023 13:08:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1682428116; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type; bh=P2+JEk3DfbVtRutnOkSzUKLGfLZPgasQaJjaAvnXgAI=; b=evbAWtVp8zw9vTBIUlko9H9b3/AhA8FsSPHvidWZTs4qJSTwohRn7rfcd7g9SwF4OdhH6d PMSfHgM5VoMd9T5A73hDxh6U2+RncyDrzTFSDt3cy2rcUY0v0vNyzEKvMKj7qYHk2W7RK6 Pw4sd17ggAKv1/MPQaFA6emxHgKOhOo= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1682428116; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type; bh=P2+JEk3DfbVtRutnOkSzUKLGfLZPgasQaJjaAvnXgAI=; b=LEAV1g2/bQaIi6dNwVqvJAtrp77PtUUU1GgmTenaYyHx8QUi2L4A2mFel6A+kZJHYBIptU 9HyrW72tHpBC3+DQ== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 5E2B513466; Tue, 25 Apr 2023 13:08:36 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id cIQ9FdTQR2RWCwAAMHmgww (envelope-from ); Tue, 25 Apr 2023 13:08:36 +0000 Date: Tue, 25 Apr 2023 15:08:35 +0200 (CEST) From: Richard Biener To: gcc-patches@gcc.gnu.org cc: Jan Hubicka Subject: [PATCH] tree-optimization/109609 - correctly interpret arg size in fnspec MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Message-Id: <20230425130836.5E2B513466@imap2.suse-dmz.suse.de> X-Spam-Status: No, score=-11.8 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: By majority vote and a hint from the API name which is arg_max_access_size_given_by_arg_p this interprets a memory access size specified as given as other argument such as for strncpy in the testcase which has "1cO313" as specifying the _maximum_ size read/written rather than the exact size. There are two uses interpreting it that way already and one differing. The following adjusts the differing and clarifies the documentation. Bootstrap & regtest running on x86_64-unknown-linux-gnu. It looks like arg_access_size_given_by_type_p is interpreted in a similar way but the API doesn't reflect this (no _max). On IRC we discussed it would be nice to have both, exact and non-exact size (for example use 'a'..'j' for the alternate variant). I still wonder if my interpretation is correct in that '1'..'9' specify a _bound_ for the size. Honza, do you remember why you wrote the IPA modref users this way? Was that intentional? Thus is my reverse engineering of the desired semantics correct? Thanks, Richard. PR tree-optimization/109609 * attr-fnspec.h (arg_max_access_size_given_by_arg_p): Clarify semantics. * tree-ssa-alias.cc (check_fnspec): Correctly interpret the size given by arg_max_access_size_given_by_arg_p as maximum, not exact, size. * gcc.dg/torture/pr109609.c: New testcase. --- gcc/attr-fnspec.h | 4 ++-- gcc/testsuite/gcc.dg/torture/pr109609.c | 26 +++++++++++++++++++++++++ gcc/tree-ssa-alias.cc | 18 ++++++++++++++--- 3 files changed, 43 insertions(+), 5 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/torture/pr109609.c diff --git a/gcc/attr-fnspec.h b/gcc/attr-fnspec.h index acf1c5f6be7..99d5f896e8b 100644 --- a/gcc/attr-fnspec.h +++ b/gcc/attr-fnspec.h @@ -54,7 +54,7 @@ ' ' nothing is known 't' the size of value written/read corresponds to the size of of the pointed-to type of the argument type - '1'...'9' specifies the size of value written/read is given by the + '1'...'9' specifies the size of value written/read is bound by the specified argument */ @@ -169,7 +169,7 @@ public: && str[idx] != 'x' && str[idx] != 'X'; } - /* Return true if load of memory pointed to by argument I is specified + /* Return true if load of memory pointed to by argument I is bound by another argument. In this case set ARG. */ bool arg_max_access_size_given_by_arg_p (unsigned int i, unsigned int *arg) diff --git a/gcc/testsuite/gcc.dg/torture/pr109609.c b/gcc/testsuite/gcc.dg/torture/pr109609.c new file mode 100644 index 00000000000..0e191cd1ee8 --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/pr109609.c @@ -0,0 +1,26 @@ +/* { dg-do run } */ + +#define N 23 +#define MAX_LEN 13 +char dst[N + 1]; + +void __attribute__((noipa)) +invert(const char *id) +{ + char buf[MAX_LEN]; + char *ptr = buf + sizeof(buf); // start from the end of buf + *(--ptr) = '\0'; // terminate string + while (*id && ptr > buf) { + *(--ptr) = *(id++); // copy id backwards + } + __builtin_strncpy(dst, ptr, N); // copy ptr/buf to dst +} + + +int main() +{ + invert("abcde"); + if (__builtin_strcmp(dst, "edcba")) + __builtin_abort(); + return 0; +} diff --git a/gcc/tree-ssa-alias.cc b/gcc/tree-ssa-alias.cc index 8a1ec9091fa..e0693e146bf 100644 --- a/gcc/tree-ssa-alias.cc +++ b/gcc/tree-ssa-alias.cc @@ -2726,9 +2726,21 @@ check_fnspec (gcall *call, ao_ref *ref, bool clobber) t = TREE_CHAIN (t); size = TYPE_SIZE_UNIT (TREE_TYPE (TREE_VALUE (t))); } - ao_ref_init_from_ptr_and_size (&dref, - gimple_call_arg (call, i), - size); + poly_int64 size_hwi; + if (size + && poly_int_tree_p (size, &size_hwi) + && coeffs_in_range_p (size_hwi, 0, + HOST_WIDE_INT_MAX / BITS_PER_UNIT)) + { + size_hwi = size_hwi * BITS_PER_UNIT; + ao_ref_init_from_ptr_and_range (&dref, + gimple_call_arg (call, i), + true, 0, -1, size_hwi); + } + else + ao_ref_init_from_ptr_and_range (&dref, + gimple_call_arg (call, i), + false, 0, -1, -1); if (refs_may_alias_p_1 (&dref, ref, false)) return 1; } -- 2.35.3