From 99adff5b55e33f987c3f174c97aa0e5dd47e4731 Mon Sep 17 00:00:00 2001 From: Philip Reames Date: Tue, 26 Feb 2019 04:30:33 +0000 Subject: [PATCH] [ARM] Be super conservative about atomics As requested during review of D57601 https://reviews.llvm.org/D57601, be equally conservative for atomic MMOs as for volatile MMOs in all in tree backends. At the moment, all atomic MMOs are also volatile, but I'm about to change that. Differential Revision: https://reviews.llvm.org/D58490 Note: D58498 landed in several pieces as individual backends were approved. This is the last chunk. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@354845 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/ARM/ARMLoadStoreOptimizer.cpp | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/lib/Target/ARM/ARMLoadStoreOptimizer.cpp b/lib/Target/ARM/ARMLoadStoreOptimizer.cpp index 132030d0393..13b5445eaba 100644 --- a/lib/Target/ARM/ARMLoadStoreOptimizer.cpp +++ b/lib/Target/ARM/ARMLoadStoreOptimizer.cpp @@ -1580,7 +1580,9 @@ static bool isMemoryOp(const MachineInstr &MI) { const MachineMemOperand &MMO = **MI.memoperands_begin(); // Don't touch volatile memory accesses - we may be changing their order. - if (MMO.isVolatile()) + // TODO: We could allow unordered and monotonic atomics here, but we need to + // make sure the resulting ldm/stm is correctly marked as atomic. + if (MMO.isVolatile() || MMO.isAtomic()) return false; // Unaligned ldr/str is emulated by some kernels, but unaligned ldm/stm is @@ -2144,7 +2146,8 @@ ARMPreAllocLoadStoreOpt::CanFormLdStDWord(MachineInstr *Op0, MachineInstr *Op1, // At the moment, we ignore the memoryoperand's value. // If we want to use AliasAnalysis, we should check it accordingly. if (!Op0->hasOneMemOperand() || - (*Op0->memoperands_begin())->isVolatile()) + (*Op0->memoperands_begin())->isVolatile() || + (*Op0->memoperands_begin())->isAtomic()) return false; unsigned Align = (*Op0->memoperands_begin())->getAlignment(); -- 2.50.1