From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2140) id 4B80C3857413; Thu, 5 May 2022 02:42:21 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 4B80C3857413 Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Alexandre Oliva To: gcc-cvs@gcc.gnu.org Subject: [gcc(refs/users/aoliva/heads/testme)] Reject unaligned subregs when strict alignment is required X-Act-Checkin: gcc X-Git-Author: Alexandre Oliva X-Git-Refname: refs/users/aoliva/heads/testme X-Git-Oldrev: 3a9edb99148c52ac5890be8aa61548eac8692672 X-Git-Newrev: 3d8a853f35a2a5e259d84c26580224d4d1de10e8 Message-Id: <20220505024221.4B80C3857413@sourceware.org> Date: Thu, 5 May 2022 02:42:21 +0000 (GMT) X-BeenThere: gcc-cvs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-cvs mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 05 May 2022 02:42:21 -0000 https://gcc.gnu.org/g:3d8a853f35a2a5e259d84c26580224d4d1de10e8 commit 3d8a853f35a2a5e259d84c26580224d4d1de10e8 Author: Alexandre Oliva Date: Wed May 4 23:41:39 2022 -0300 Reject unaligned subregs when strict alignment is required The testcase for pr100106, compiled with optimization for 32-bit powerpc -mcpu=604 with -mstrict-align expands the initialization of a union from a float _Complex value into a load from an SCmode constant pool entry, aligned to 4 bytes, into a DImode pseudo, requiring 8-byte alignment. The patch that introduced the testcase modified simplify_subreg to avoid changing the MEM to outermode, but simplify_gen_subreg still creates a SUBREG or a MEM that would require stricter alignment than MEM's, and lra_constraints appears to get confused by that, repeatedly creating unsatisfiable reloads for the SUBREG until it exceeds the insn count. Avoiding the unaligned SUBREG, expand splits the DImode dest into SUBREGs and loads each SImode word of the constant pool with the proper alignment. for gcc/ChangeLog PR target/100106 * emit-rtl.c (validate_subreg): Reject a SUBREG of a MEM that requires stricter alignment than MEM's. for gcc/testsuite/ChangeLog PR target/100106 * gcc.target/powerpc/pr100106-sa.c: New. TN: V502-036 Diff: --- gcc/emit-rtl.cc | 3 +++ gcc/testsuite/gcc.target/powerpc/pr100106-sa.c | 4 ++++ 2 files changed, 7 insertions(+) diff --git a/gcc/emit-rtl.cc b/gcc/emit-rtl.cc index 1e02ae254d0..642e47eada0 100644 --- a/gcc/emit-rtl.cc +++ b/gcc/emit-rtl.cc @@ -982,6 +982,9 @@ validate_subreg (machine_mode omode, machine_mode imode, return subreg_offset_representable_p (regno, imode, offset, omode); } + else if (reg && MEM_P (reg) + && STRICT_ALIGNMENT && MEM_ALIGN (reg) < GET_MODE_ALIGNMENT (omode)) + return false; /* The outer size must be ordered wrt the register size, otherwise we wouldn't know at compile time how many registers the outer diff --git a/gcc/testsuite/gcc.target/powerpc/pr100106-sa.c b/gcc/testsuite/gcc.target/powerpc/pr100106-sa.c new file mode 100644 index 00000000000..1cd6b595a5b --- /dev/null +++ b/gcc/testsuite/gcc.target/powerpc/pr100106-sa.c @@ -0,0 +1,4 @@ +/* { dg-do compile } */ +/* { dg-options "-mcpu=604 -O -mstrict-align" } */ + +#include "../../gcc.c-torture/compile/pr100106.c"