From 0fd1a2cc65a3642d07e4da99e6547818868e64e3 Mon Sep 17 00:00:00 2001 From: Bjorn Pettersson Date: Mon, 19 Dec 2016 11:20:57 +0000 Subject: [PATCH] [CodeGen] Make MachineInstr::isIdenticalTo() symmetric. Summary: MachineInstr::isIdenticalTo() is for some reason not symmetric when comparing bundles, which gives us the property: I1->isIdenticalTo(*I2) != I2->isIdenticalTo(*I1) when comparing bundles where one bundle is longer than the other. This patch makes sure that bundles of different length always are considered as not being identical. Thus, the result of the comparison will be the same regardless of which side that happens to be to the left. Reviewers: dexonsmith, jonpa, andrew.w.kaylor Subscribers: llvm-commits, mehdi_amini Differential Revision: https://reviews.llvm.org/D27508 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290095 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/MachineInstr.cpp | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/lib/CodeGen/MachineInstr.cpp b/lib/CodeGen/MachineInstr.cpp index 56fa41ebf4d..70ef3563f1a 100644 --- a/lib/CodeGen/MachineInstr.cpp +++ b/lib/CodeGen/MachineInstr.cpp @@ -1000,16 +1000,24 @@ bool MachineInstr::isIdenticalTo(const MachineInstr &Other, return false; if (isBundle()) { - // Both instructions are bundles, compare MIs inside the bundle. + // We have passed the test above that both instructions have the same + // opcode, so we know that both instructions are bundles here. Let's compare + // MIs inside the bundle. + assert(Other.isBundle() && "Expected that both instructions are bundles."); MachineBasicBlock::const_instr_iterator I1 = getIterator(); - MachineBasicBlock::const_instr_iterator E1 = getParent()->instr_end(); MachineBasicBlock::const_instr_iterator I2 = Other.getIterator(); - MachineBasicBlock::const_instr_iterator E2 = Other.getParent()->instr_end(); - while (++I1 != E1 && I1->isInsideBundle()) { + // Loop until we analysed the last intruction inside at least one of the + // bundles. + while (I1->isBundledWithSucc() && I2->isBundledWithSucc()) { + ++I1; ++I2; - if (I2 == E2 || !I2->isInsideBundle() || !I1->isIdenticalTo(*I2, Check)) + if (!I1->isIdenticalTo(*I2, Check)) return false; } + // If we've reached the end of just one of the two bundles, but not both, + // the instructions are not identical. + if (I1->isBundledWithSucc() || I2->isBundledWithSucc()) + return false; } // Check operands to make sure they match. -- 2.50.1