From 7adb9e06fd0dd49891e491cba9705e9dd119440e Mon Sep 17 00:00:00 2001 From: Max Kazantsev Date: Wed, 8 Apr 2020 17:22:53 +0700 Subject: [PATCH] [LoopLoadElim] Add test showing that LoopLoadElim doesn't work correctly with new PM --- .../Transforms/Scalar/LoopLoadElimination.cpp | 1 + .../LoopLoadElim/new-pm-preheader-problem.ll | 27 +++++++++++++++++++ 2 files changed, 28 insertions(+) create mode 100644 llvm/test/Transforms/LoopLoadElim/new-pm-preheader-problem.ll diff --git a/llvm/lib/Transforms/Scalar/LoopLoadElimination.cpp b/llvm/lib/Transforms/Scalar/LoopLoadElimination.cpp index 4eac40e2a527..b074a11be5b5 100644 --- a/llvm/lib/Transforms/Scalar/LoopLoadElimination.cpp +++ b/llvm/lib/Transforms/Scalar/LoopLoadElimination.cpp @@ -432,6 +432,7 @@ public: Value *Ptr = Cand.Load->getPointerOperand(); auto *PtrSCEV = cast(PSE.getSCEV(Ptr)); auto *PH = L->getLoopPreheader(); + assert(PH && "Preheader should exist!"); Value *InitialPtr = SEE.expandCodeFor(PtrSCEV->getStart(), Ptr->getType(), PH->getTerminator()); Value *Initial = new LoadInst( diff --git a/llvm/test/Transforms/LoopLoadElim/new-pm-preheader-problem.ll b/llvm/test/Transforms/LoopLoadElim/new-pm-preheader-problem.ll new file mode 100644 index 000000000000..a63dc29faca7 --- /dev/null +++ b/llvm/test/Transforms/LoopLoadElim/new-pm-preheader-problem.ll @@ -0,0 +1,27 @@ +; XFAIL: * +; RUN: opt -passes=loop-load-elim -S < %s | FileCheck %s +; This test demonstrates an assertion failure due to missing preheader in new PM. +; REQUIRES: asserts +target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128" + +define void @test(i32* noalias nocapture %A, i32* noalias nocapture readonly %B, i64 %N, i1 %C) { +entry: + br i1 %C, label %for.body, label %for.end + +; CHECK: test +for.body: + %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ] + %arrayidx = getelementptr inbounds i32, i32* %A, i64 %indvars.iv + %load = load i32, i32* %arrayidx, align 4 + %arrayidx2 = getelementptr inbounds i32, i32* %B, i64 %indvars.iv + %load_1 = load i32, i32* %arrayidx2, align 4 + %add = add i32 %load_1, %load + %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1 + %arrayidx_next = getelementptr inbounds i32, i32* %A, i64 %indvars.iv.next + store i32 %add, i32* %arrayidx_next, align 4 + %exitcond = icmp eq i64 %indvars.iv.next, %N + br i1 %exitcond, label %for.end, label %for.body + +for.end: + ret void +}