From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1592) id C95C738543BE; Fri, 13 Jan 2023 18:33:37 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org C95C738543BE DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1673634817; bh=Vf0mYvn/1EGw4HBU9NDVGkWBA8BfM9UaUcQNvw5gh6U=; h=From:To:Subject:Date:From; b=gmUW6ZjamwwZeocLWcPp6Ug2NcJK1Q7QmpnKHfcyOInjt2DgZjEIh42OzgFDNQNOE EXt0WAYETX/lA9pnbJunGxP9CPrFSLdzmpz5LU/HPylDkGrmed6Uvif05776Wht7wo hVTrPggdmJ/lzt3o0BSoFasFKXJZef9M3xSNBVVw= MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: Alexander Monakov To: gcc-cvs@gcc.gnu.org Subject: [gcc r13-5154] sched-deps: do not schedule pseudos across calls [PR108117] X-Act-Checkin: gcc X-Git-Author: Alexander Monakov X-Git-Refname: refs/heads/master X-Git-Oldrev: b4b1c6aa6d28d3afe989a6dc3210606a3d55a367 X-Git-Newrev: 733a1b777f16cd397b43a242d9c31761f66d3da8 Message-Id: <20230113183337.C95C738543BE@sourceware.org> Date: Fri, 13 Jan 2023 18:33:37 +0000 (GMT) List-Id: https://gcc.gnu.org/g:733a1b777f16cd397b43a242d9c31761f66d3da8 commit r13-5154-g733a1b777f16cd397b43a242d9c31761f66d3da8 Author: Alexander Monakov Date: Fri Jan 13 21:04:02 2023 +0300 sched-deps: do not schedule pseudos across calls [PR108117] Scheduling across calls in the pre-RA scheduler is problematic: we do not take liveness info into account, and are thus prone to extending lifetime of a pseudo over the loop, requiring a callee-saved hardreg or causing a spill. If current function called a setjmp, lifting an assignment over a call may be incorrect if a longjmp would happen before the assignment. Thanks to Jose Marchesi for testing on AArch64. gcc/ChangeLog: PR rtl-optimization/108117 PR rtl-optimization/108132 * sched-deps.cc (deps_analyze_insn): Do not schedule across calls before reload. gcc/testsuite/ChangeLog: PR rtl-optimization/108117 PR rtl-optimization/108132 * gcc.dg/pr108117.c: New test. Diff: --- gcc/sched-deps.cc | 9 ++++++++- gcc/testsuite/gcc.dg/pr108117.c | 30 ++++++++++++++++++++++++++++++ 2 files changed, 38 insertions(+), 1 deletion(-) diff --git a/gcc/sched-deps.cc b/gcc/sched-deps.cc index 08877b344b6..f9371b81fb4 100644 --- a/gcc/sched-deps.cc +++ b/gcc/sched-deps.cc @@ -3688,7 +3688,14 @@ deps_analyze_insn (class deps_desc *deps, rtx_insn *insn) CANT_MOVE (insn) = 1; - if (find_reg_note (insn, REG_SETJMP, NULL)) + if (!reload_completed) + { + /* Scheduling across calls may increase register pressure by extending + live ranges of pseudos over the call. Worse, in presence of setjmp + it may incorrectly move up an assignment over a longjmp. */ + reg_pending_barrier = MOVE_BARRIER; + } + else if (find_reg_note (insn, REG_SETJMP, NULL)) { /* This is setjmp. Assume that all registers, not just hard registers, may be clobbered by this call. */ diff --git a/gcc/testsuite/gcc.dg/pr108117.c b/gcc/testsuite/gcc.dg/pr108117.c new file mode 100644 index 00000000000..ae151693e2f --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr108117.c @@ -0,0 +1,30 @@ +/* { dg-do run } */ +/* { dg-require-effective-target nonlocal_goto } */ +/* { dg-options "-O2 -fschedule-insns" } */ + +#include +#include + +jmp_buf ex_buf; + +__attribute__((noipa)) +void fn_throw(int x) +{ + if (x) + longjmp(ex_buf, 1); +} + +int main(void) +{ + int vb = 0; // NB: not volatile, not modified after setjmp + + if (!setjmp(ex_buf)) { + fn_throw(1); + vb = 1; // not reached in the abstract machine + } + + if (vb) { + printf("Failed, vb = %d!\n", vb); + return 1; + } +}