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[Polly][ScopBuilder] Use only modeled instructions to compute statement granularity. 

ScopBuilder distributes independent instructions between statements.
Only modeled (e.g. not synthesizable) instructions are represented.
To compute independence, non-modeled instructions were used in some
parts of determining instruction independence, which could lead to the
re-introduction of non-model instructions.

In particular, required invariant loads could be added to instruction
list, which then led to redundant MemoryAccesses for such a load.

This fixes llvm.org/PR48059.
This commit is contained in:
Michael Kruse 2020-11-10 02:37:35 -06:00
parent 19f0770923
commit e408935bb5
2 changed files with 39 additions and 7 deletions
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14
polly/lib/Analysis/ScopBuilder.cpp
View File

@ -2132,11 +2132,11 @@ void ScopBuilder::buildEqivClassBlockStmts(BasicBlock *BB) {
// The order of statements must be preserved w.r.t. their ordered
// instructions. Without this explicit scan, we would also use non-ordered
// instructions (whose order is arbitrary) to determine statement order.
for (Instruction &Inst : *BB) {
if (!isOrderedInstruction(&Inst))
for (Instruction *Inst : ModeledInsts) {
if (!isOrderedInstruction(Inst))
continue;
auto LeaderIt = UnionFind.findLeader(&Inst);
auto LeaderIt = UnionFind.findLeader(Inst);
if (LeaderIt == UnionFind.member_end())
continue;
@ -2146,15 +2146,15 @@ void ScopBuilder::buildEqivClassBlockStmts(BasicBlock *BB) {
// Collect the instructions of all leaders. UnionFind's member iterator
// unfortunately are not in any specific order.
for (Instruction &Inst : *BB) {
auto LeaderIt = UnionFind.findLeader(&Inst);
for (Instruction *Inst : ModeledInsts) {
auto LeaderIt = UnionFind.findLeader(Inst);
if (LeaderIt == UnionFind.member_end())
continue;
if (&Inst == MainInst)
if (Inst == MainInst)
MainLeader = *LeaderIt;
std::vector<Instruction *> &InstList = LeaderToInstList[*LeaderIt];
InstList.push_back(&Inst);
InstList.push_back(Inst);
}
// Finally build the statements.

32
polly/test/ScopInfo/invariant-load-instlist.ll Normal file
View File

@ -0,0 +1,32 @@
; RUN: opt %loadPolly -polly-scops -analyze < %s
; The load is a required invariant load and at the same time used in a store.
; Polly used to add two MemoryAccesses for it which caused an assertion to fail.
; llvm.org/PR48059
target datalayout = "e-m:w-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-pc-windows-msvc19.27.29112"
@b = external dso_local global i32, align 4
@c = external dso_local global i32*, align 8
@a = external dso_local local_unnamed_addr global i32**, align 8
define void @func() {
for.cond1.preheader.preheader:
br label %for.end12
for.end12:
br i1 undef, label %for.end12.1, label %for.end12
for.end12.1:
%0 = phi i32* [ %1, %for.end12.1 ], [ undef, %for.end12 ]
%storemerge26.1 = phi i32 [ %inc14.1, %for.end12.1 ], [ 0, %for.end12 ]
%1 = load i32*, i32** @c, align 8
store i32 0, i32* %1, align 4
%inc14.1 = add nuw nsw i32 %storemerge26.1, 1
%exitcond.1.not = icmp eq i32 %inc14.1, 35
br i1 %exitcond.1.not, label %for.inc16.1, label %for.end12.1
for.inc16.1:
ret void
}