From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1005) id D0DB63857709; Mon, 16 Oct 2023 18:24:26 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org D0DB63857709 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1697480666; bh=y1/oiSzGXygJOqGWs/olRsqy3D2jxXt2PDnIE4xF1yU=; h=From:To:Subject:Date:From; b=ClH0hLUif1AOM+9gRVKCnV0OePOyPlkH6X4lMdnOWlMP5UYcKEQDqgxVcV9BoNXdg bYU6RCYyXC6i57jE8RxdE7w91j6DnQDipLIIrmbewVAde1mt+CEjoq0NzILjn1o+lk Cx0uqCy0ZfPOb2tiKpRkorneQFW8PTqBZ6QNPsjQ= Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Michael Meissner To: gcc-cvs@gcc.gnu.org Subject: [gcc(refs/users/meissner/heads/work139)] Update ChangeLog.meissner X-Act-Checkin: gcc X-Git-Author: Michael Meissner X-Git-Refname: refs/users/meissner/heads/work139 X-Git-Oldrev: 6b89ca6ea6649b6a549077530f050c82245aded0 X-Git-Newrev: 66c36aef032ce8876620f44c6ce23631e9011235 Message-Id: <20231016182426.D0DB63857709@sourceware.org> Date: Mon, 16 Oct 2023 18:24:26 +0000 (GMT) List-Id: https://gcc.gnu.org/g:66c36aef032ce8876620f44c6ce23631e9011235 commit 66c36aef032ce8876620f44c6ce23631e9011235 Author: Michael Meissner Date: Thu Oct 12 00:10:00 2023 -0400 Update ChangeLog.meissner Diff: --- gcc/ChangeLog.meissner | 45 +-------------------------------------------- 1 file changed, 1 insertion(+), 44 deletions(-) diff --git a/gcc/ChangeLog.meissner b/gcc/ChangeLog.meissner index 2f6352e33f00..17fa7658723b 100644 --- a/gcc/ChangeLog.meissner +++ b/gcc/ChangeLog.meissner @@ -64,48 +64,7 @@ gcc/testsuite/ * gcc.target/powerpc/vector-pair-switch3.c: New test. * gcc.target/powerpc/vector-pair-switch4.c: New test. -==================== Branch work139, patch #2 ==================== - -PowerPC: Do not depend on an undefined shift - -I was building a cross compiler to PowerPC on my x86_86 workstation with the -latest version of GCC on October 11th. I could not build the compiler on the -x86_64 system as it died in building libgcc. I looked into it, and I -discovered the compiler was recursing until it ran out of stack space. If I -build a native compiler with the same sources on a PowerPC system, it builds -fine. - -I traced this down to a change made around October 10th: - -| commit 8f1a70a4fbcc6441c70da60d4ef6db1e5635e18a (HEAD) -| Author: Jiufu Guo -| Date: Tue Jan 10 20:52:33 2023 +0800 -| -| rs6000: build constant via li/lis;rldicl/rldicr -| -| If a constant is possible left/right cleaned on a rotated value from -| a negative value of "li/lis". Then, using "li/lis ; rldicl/rldicr" -| to build the constant. - -The code was doing a -1 << 64 which is undefined behavior because different -machines produce different results. On the x86_64 system, (-1 << 64) produces --1 while on a PowerPC 64-bit system, (-1 << 64) produces 0. The x86_64 then -recurses until the stack runs out of space. - -If I apply this patch, the compiler builds fine on both x86_64 as a PowerPC -crosss compiler and on a native PowerPC system. - -2023-10-12 Michael Meissner - -gcc/ - - PR target/111778 - * config/rs6000/rs6000.cc (can_be_built_by_li_lis_and_rldicl): Protect - code from shifts that are undefined. - (can_be_built_by_li_lis_and_rldicr): Likewise. - (can_be_built_by_li_and_rldic): Likewise. - -==================== Branch work139, patch #1 was reverted ==================== +==================== Branch work139, patch #2 applied to trunk ==================== ==================== Branch work139, baseline ==================== @@ -142,8 +101,6 @@ libgcc/ * ChangeLog.meissner: New file. -==================== Branch work139, baseline ==================== - 2023-10-11 Michael Meissner Clone branch