From 1c528e8f1b29b48bcb37a3a6e5e4c97572300102 Mon Sep 17 00:00:00 2001 From: Alina Sbirlea Date: Tue, 20 Aug 2019 22:29:06 +0000 Subject: [PATCH] [MemorySSA] Fix existing phis when inserting defs. Summary: When inserting a new Def, and inserting Phis in the IDF when needed, also mark the already existing Phis in the IDF as non-optimized, since these may need fixing as well. In the test attached, there is a Phi in the IDF that happens to be trivial, and is wrongfully removed by the call to getLastDef that follows. This is a valid situation and the existing IDF Phis need to marked as "may need fixing" as well. Resolves PR43044. Reviewers: george.burgess.iv Subscribers: Prazek, sanjoy.google, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D66495 llvm-svn: 369464 --- llvm/lib/Analysis/MemorySSAUpdater.cpp | 20 ++++++++----- llvm/test/Analysis/MemorySSA/PR43044.ll | 52 +++++++++++++++++++++++++++++++++ 2 files changed, 64 insertions(+), 8 deletions(-) create mode 100644 llvm/test/Analysis/MemorySSA/PR43044.ll diff --git a/llvm/lib/Analysis/MemorySSAUpdater.cpp b/llvm/lib/Analysis/MemorySSAUpdater.cpp index 87818c5..e63a9b8 100644 --- a/llvm/lib/Analysis/MemorySSAUpdater.cpp +++ b/llvm/lib/Analysis/MemorySSAUpdater.cpp @@ -341,16 +341,20 @@ void MemorySSAUpdater::insertDef(MemoryDef *MD, bool RenameUses) { IDFs.setDefiningBlocks(DefiningBlocks); IDFs.calculate(IDFBlocks); SmallVector, 4> NewInsertedPHIs; - for (auto *BBIDF : IDFBlocks) - if (!MSSA->getMemoryAccess(BBIDF)) { - auto *MPhi = MSSA->createMemoryPhi(BBIDF); + for (auto *BBIDF : IDFBlocks) { + auto *MPhi = MSSA->getMemoryAccess(BBIDF); + if (!MPhi) { + MPhi = MSSA->createMemoryPhi(BBIDF); NewInsertedPHIs.push_back(MPhi); - // Add the phis created into the IDF blocks to NonOptPhis, so they are - // not optimized out as trivial by the call to getPreviousDefFromEnd - // below. Once they are complete, all these Phis are added to the - // FixupList, and removed from NonOptPhis inside fixupDefs(). - NonOptPhis.insert(MPhi); } + // Add the phis created into the IDF blocks to NonOptPhis, so they are + // not optimized out as trivial by the call to getPreviousDefFromEnd + // below. Once they are complete, all these Phis are added to the + // FixupList, and removed from NonOptPhis inside fixupDefs(). + // Existing Phis in IDF may need fixing as well, and potentially be + // trivial before this insertion, hence add all IDF Phis. See PR43044. + NonOptPhis.insert(MPhi); + } for (auto &MPhi : NewInsertedPHIs) { auto *BBIDF = MPhi->getBlock(); diff --git a/llvm/test/Analysis/MemorySSA/PR43044.ll b/llvm/test/Analysis/MemorySSA/PR43044.ll new file mode 100644 index 0000000..a0b2cf7 --- /dev/null +++ b/llvm/test/Analysis/MemorySSA/PR43044.ll @@ -0,0 +1,52 @@ +; RUN: opt -loop-rotate -licm -enable-mssa-loop-dependency -verify-memoryssa %s -S | FileCheck %s +; REQUIRES: asserts + +target datalayout = "E-m:e-i1:8:16-i8:8:16-i64:64-f128:64-v128:64-a:8:16-n32:64" +target triple = "s390x-ibm-linux" + +declare void @llvm.lifetime.end.p0i8(i64 immarg, i8* nocapture) + +; CHECK-LABEL: @func_42() +define void @func_42() { +entry: + br label %for.cond1050 + +for.cond1050.loopexit: ; preds = %for.cond1373 + br label %for.cond1050 + +for.cond1050: ; preds = %for.cond1050.loopexit, %entry + %storemerge6 = phi i32 [ 2, %entry ], [ 0, %for.cond1050.loopexit ] + %cmp1051 = icmp sgt i32 %storemerge6, -1 + br i1 %cmp1051, label %for.cond1055.preheader, label %cleanup1400.loopexit1 + +for.cond1055.preheader: ; preds = %for.cond1050 + store i64 0, i64* null, align 8 + %0 = load i64, i64* null, align 8 + %tobool1383 = icmp eq i64 %0, 0 + br i1 %tobool1383, label %for.cond1055.preheader.cleanup1400.loopexit.split_crit_edge, label %for.cond1055.preheader.for.cond1055.preheader.split_crit_edge + +for.cond1055.preheader.for.cond1055.preheader.split_crit_edge: ; preds = %for.cond1055.preheader + br label %for.body1376 + +for.cond1055.preheader.cleanup1400.loopexit.split_crit_edge: ; preds = %for.cond1055.preheader + br label %cleanup1400.loopexit.split + +for.cond1373: ; preds = %for.body1376 + br i1 true, label %for.body1376, label %for.cond1050.loopexit + +for.body1376: ; preds = %for.cond1373, %for.cond1055.preheader.for.cond1055.preheader.split_crit_edge + br i1 false, label %cleanup1400.loopexit, label %for.cond1373 + +cleanup1400.loopexit: ; preds = %for.body1376 + br label %cleanup1400.loopexit.split + +cleanup1400.loopexit.split: ; preds = %cleanup1400.loopexit, %for.cond1055.preheader.cleanup1400.loopexit.split_crit_edge + br label %cleanup1400 + +cleanup1400.loopexit1: ; preds = %for.cond1050 + br label %cleanup1400 + +cleanup1400: ; preds = %cleanup1400.loopexit1, %cleanup1400.loopexit.split + call void @llvm.lifetime.end.p0i8(i64 4, i8* nonnull undef) + unreachable +} -- 2.7.4