From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2205) id 191653857C5A; Thu, 10 Mar 2022 11:22:51 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 191653857C5A MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: Tom de Vries To: gcc-cvs@gcc.gnu.org Subject: [gcc r12-7585] [nvptx] Handle unused result in nvptx_unisimt_handle_set X-Act-Checkin: gcc X-Git-Author: Tom de Vries X-Git-Refname: refs/heads/master X-Git-Oldrev: 3ebcc053a4bd32973762b671b444730baf558805 X-Git-Newrev: 3e743d654b3598d54b3c2eb837a48baeac00a543 Message-Id: <20220310112251.191653857C5A@sourceware.org> Date: Thu, 10 Mar 2022 11:22:51 +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, 10 Mar 2022 11:22:51 -0000 https://gcc.gnu.org/g:3e743d654b3598d54b3c2eb837a48baeac00a543 commit r12-7585-g3e743d654b3598d54b3c2eb837a48baeac00a543 Author: Tom de Vries Date: Mon Mar 7 15:57:11 2022 +0100 [nvptx] Handle unused result in nvptx_unisimt_handle_set For an example: ... #pragma omp target map(tofrom: counter_N0) #pragma omp simd for (int i = 0 ; i < 1 ; i++ ) { #pragma omp atomic update counter_N0 = counter_N0 + 1 ; } ... I noticed that the result of the atomic update (%r30) is propagated: ... @%r33 atom.add.u32 _, [%r29], 1; shfl.sync.idx.b32 %r30, %r30, %r32, 31, 0xffffffff; ... even though it is unused (which is why the bit bucket operand _ is used). Fix this by not emitting the shuffle in this case, such that we have instead: ... @%r33 atom.add.u32 _, [%r29], 1; bar.warp.sync 0xffffffff; ... Tested on nvptx. gcc/ChangeLog: 2022-03-07 Tom de Vries * config/nvptx/nvptx.cc (nvptx_unisimt_handle_set): Handle unused result. gcc/testsuite/ChangeLog: 2022-03-07 Tom de Vries * gcc.target/nvptx/uniform-simt-4.c: New test. Diff: --- gcc/config/nvptx/nvptx.cc | 4 +++- gcc/testsuite/gcc.target/nvptx/uniform-simt-4.c | 22 ++++++++++++++++++++++ 2 files changed, 25 insertions(+), 1 deletion(-) diff --git a/gcc/config/nvptx/nvptx.cc b/gcc/config/nvptx/nvptx.cc index 14911bd15f1..c41e305a34f 100644 --- a/gcc/config/nvptx/nvptx.cc +++ b/gcc/config/nvptx/nvptx.cc @@ -3274,7 +3274,9 @@ static bool nvptx_unisimt_handle_set (rtx set, rtx_insn *insn, rtx master) { rtx reg; - if (GET_CODE (set) == SET && REG_P (reg = SET_DEST (set))) + if (GET_CODE (set) == SET + && REG_P (reg = SET_DEST (set)) + && find_reg_note (insn, REG_UNUSED, reg) == NULL_RTX) { emit_insn_after (nvptx_gen_shuffle (reg, reg, master, SHUFFLE_IDX), insn); diff --git a/gcc/testsuite/gcc.target/nvptx/uniform-simt-4.c b/gcc/testsuite/gcc.target/nvptx/uniform-simt-4.c new file mode 100644 index 00000000000..c33de7a4111 --- /dev/null +++ b/gcc/testsuite/gcc.target/nvptx/uniform-simt-4.c @@ -0,0 +1,22 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -muniform-simt -mptx=_" } */ + +enum memmodel +{ + MEMMODEL_RELAXED = 0 +}; + +unsigned long long int *p64; +unsigned long long int v64; + +int +main() +{ + __atomic_fetch_add (p64, v64, MEMMODEL_RELAXED); + + return 0; +} + +/* { dg-final { scan-assembler-times "atom.add.u64\[\t \]+_," 1 } } */ +/* { dg-final { scan-assembler-times "bar.warp.sync" 1 } } */ +/* { dg-final { scan-assembler-not "shfl.sync.idx" } } */