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[MemorySSA & LoopPassManager] Update MemorySSA in formDedicatedExitBlocks. 

MemorySSA is now updated when forming dedicated exit blocks.
Resolves PR40037.

llvm-svn: 354623
This commit is contained in:
Alina Sbirlea 2019-02-21 21:13:34 +00:00
parent 475042d5b1
commit 97468e9282
6 changed files with 129 additions and 11 deletions
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2
llvm/include/llvm/Transforms/Utils/LoopUtils.h
View File

@ -59,7 +59,7 @@ BasicBlock *InsertPreheaderForLoop(Loop *L, DominatorTree *DT, LoopInfo *LI,
/// predecessors to use a dedicated loop exit block. We update the dominator
/// tree and loop info if provided, and will preserve LCSSA if requested.
bool formDedicatedExitBlocks(Loop *L, DominatorTree *DT, LoopInfo *LI,
bool PreserveLCSSA);
MemorySSAUpdater *MSSAU, bool PreserveLCSSA);
/// Ensures LCSSA form for every instruction from the Worklist in the scope of
/// innermost containing loop.

18
llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp
View File

@ -267,7 +267,8 @@ static void rewritePHINodesForExitAndUnswitchedBlocks(BasicBlock &ExitBB,
/// loops reachable and need to move the current loop up the loop nest or even
/// to an entirely separate nest.
static void hoistLoopToNewParent(Loop &L, BasicBlock &Preheader,
DominatorTree &DT, LoopInfo &LI) {
DominatorTree &DT, LoopInfo &LI,
MemorySSAUpdater *MSSAU) {
// If the loop is already at the top level, we can't hoist it anywhere.
Loop *OldParentL = L.getParentLoop();
if (!OldParentL)
@ -328,7 +329,8 @@ static void hoistLoopToNewParent(Loop &L, BasicBlock &Preheader,
// unswitching it is possible to get new non-dedicated exits out of parent
// loop so let's conservatively form dedicated exit blocks and figure out
// if we can optimize later.
formDedicatedExitBlocks(OldContainingL, &DT, &LI, /*PreserveLCSSA*/ true);
formDedicatedExitBlocks(OldContainingL, &DT, &LI, MSSAU,
/*PreserveLCSSA*/ true);
}
}
@ -535,7 +537,10 @@ static bool unswitchTrivialBranch(Loop &L, BranchInst &BI, DominatorTree &DT,
// If this was full unswitching, we may have changed the nesting relationship
// for this loop so hoist it to its correct parent if needed.
if (FullUnswitch)
hoistLoopToNewParent(L, *NewPH, DT, LI);
hoistLoopToNewParent(L, *NewPH, DT, LI, MSSAU);
if (MSSAU && VerifyMemorySSA)
MSSAU->getMemorySSA()->verifyMemorySSA();
LLVM_DEBUG(dbgs() << " done: unswitching trivial branch...\n");
++NumTrivial;
@ -804,7 +809,10 @@ static bool unswitchTrivialSwitch(Loop &L, SwitchInst &SI, DominatorTree &DT,
// We may have changed the nesting relationship for this loop so hoist it to
// its correct parent if needed.
hoistLoopToNewParent(L, *NewPH, DT, LI);
hoistLoopToNewParent(L, *NewPH, DT, LI, MSSAU);
if (MSSAU && VerifyMemorySSA)
MSSAU->getMemorySSA()->verifyMemorySSA();
++NumTrivial;
++NumSwitches;
@ -2239,7 +2247,7 @@ static void unswitchNontrivialInvariants(
// introduced new, non-dedicated exits. At least try to re-form dedicated
// exits for these loops. This may fail if they couldn't have dedicated
// exits to start with.
formDedicatedExitBlocks(&UpdateL, &DT, &LI, /*PreserveLCSSA*/ true);
formDedicatedExitBlocks(&UpdateL, &DT, &LI, MSSAU, /*PreserveLCSSA*/ true);
};
// For non-child cloned loops and hoisted loops, we just need to update LCSSA

4
llvm/lib/Transforms/Utils/LoopSimplify.cpp
View File

@ -317,7 +317,7 @@ static Loop *separateNestedLoop(Loop *L, BasicBlock *Preheader,
// Split edges to exit blocks from the inner loop, if they emerged in the
// process of separating the outer one.
formDedicatedExitBlocks(L, DT, LI, PreserveLCSSA);
formDedicatedExitBlocks(L, DT, LI, nullptr, PreserveLCSSA);
if (PreserveLCSSA) {
// Fix LCSSA form for L. Some values, which previously were only used inside
@ -530,7 +530,7 @@ ReprocessLoop:
// predecessors that are inside of the loop. This check guarantees that the
// loop preheader/header will dominate the exit blocks. If the exit block has
// predecessors from outside of the loop, split the edge now.
if (formDedicatedExitBlocks(L, DT, LI, PreserveLCSSA))
if (formDedicatedExitBlocks(L, DT, LI, nullptr, PreserveLCSSA))
Changed = true;
// If the header has more than two predecessors at this point (from the

4
llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
View File

@ -938,11 +938,11 @@ bool llvm::UnrollRuntimeLoopRemainder(Loop *L, unsigned Count,
if (OtherExits.size() > 0) {
// Generate dedicated exit blocks for the original loop, to preserve
// LoopSimplifyForm.
formDedicatedExitBlocks(L, DT, LI, PreserveLCSSA);
formDedicatedExitBlocks(L, DT, LI, nullptr, PreserveLCSSA);
// Generate dedicated exit blocks for the remainder loop if one exists, to
// preserve LoopSimplifyForm.
if (remainderLoop)
formDedicatedExitBlocks(remainderLoop, DT, LI, PreserveLCSSA);
formDedicatedExitBlocks(remainderLoop, DT, LI, nullptr, PreserveLCSSA);
}
auto UnrollResult = LoopUnrollResult::Unmodified;

4
llvm/lib/Transforms/Utils/LoopUtils.cpp
View File

@ -19,6 +19,7 @@
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/LoopPass.h"
#include "llvm/Analysis/MemorySSAUpdater.h"
#include "llvm/Analysis/MustExecute.h"
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Analysis/ScalarEvolutionAliasAnalysis.h"
@ -46,6 +47,7 @@ using namespace llvm::PatternMatch;
static const char *LLVMLoopDisableNonforced = "llvm.loop.disable_nonforced";
bool llvm::formDedicatedExitBlocks(Loop *L, DominatorTree *DT, LoopInfo *LI,
MemorySSAUpdater *MSSAU,
bool PreserveLCSSA) {
bool Changed = false;
@ -81,7 +83,7 @@ bool llvm::formDedicatedExitBlocks(Loop *L, DominatorTree *DT, LoopInfo *LI,
return false;
auto *NewExitBB = SplitBlockPredecessors(
BB, InLoopPredecessors, ".loopexit", DT, LI, nullptr, PreserveLCSSA);
BB, InLoopPredecessors, ".loopexit", DT, LI, MSSAU, PreserveLCSSA);
if (!NewExitBB)
LLVM_DEBUG(

108
llvm/test/Analysis/MemorySSA/pr40037.ll Normal file
View File

@ -0,0 +1,108 @@
; REQUIRES: asserts
; RUN: opt -S -mtriple=systemz-unknown -mcpu=z13 -O3 -enable-mssa-loop-dependency -enable-simple-loop-unswitch -verify-memoryssa < %s | FileCheck %s
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"
@g_225 = external dso_local global i16, align 2
@g_967 = external dso_local global i8, align 2
@g_853 = external dso_local global i32***, align 8
@g_320 = external dso_local global { i8, i8, i8, i8, i8, i8, i8, i8 }, align 4
; Function Attrs: nounwind
; CHECK-LABEL: @main(
define dso_local void @main() #0 {
bb:
call void @func_1()
unreachable
}
; Function Attrs: nounwind
define dso_local void @func_1() #0 {
bb:
call void @func_23()
unreachable
}
; Function Attrs: nounwind
define dso_local void @func_23() #0 {
bb:
%tmp = alloca i32****, align 8
%tmp1 = alloca i32*****, align 8
store i32**** @g_853, i32***** %tmp, align 8, !tbaa !1
store i32***** %tmp, i32****** %tmp1, align 8, !tbaa !1
br label %bb2
bb2: ; preds = %bb21, %bb
br label %bb3
bb3: ; preds = %bb7, %bb2
%tmp4 = load i8, i8* @g_967, align 2, !tbaa !5
%tmp5 = sext i8 %tmp4 to i32
%tmp6 = icmp sle i32 %tmp5, 5
br i1 %tmp6, label %bb7, label %bb8
bb7: ; preds = %bb3
call void @safe_sub_func_uint64_t_u_u()
br label %bb3
bb8: ; preds = %bb3
store i16 0, i16* @g_225, align 2, !tbaa !6
br label %bb9
bb9: ; preds = %bb25, %bb8
%tmp10 = load i16, i16* @g_225, align 2, !tbaa !6
%tmp11 = sext i16 %tmp10 to i32
%tmp12 = icmp ne i32 %tmp11, 1
br i1 %tmp12, label %bb13, label %bb28
bb13: ; preds = %bb9
%tmp14 = load i32*****, i32****** %tmp1, align 8, !tbaa !1
%tmp15 = load i32****, i32***** %tmp14, align 8, !tbaa !1
%tmp16 = load i32***, i32**** %tmp15, align 8, !tbaa !1
%tmp17 = load i32**, i32*** %tmp16, align 8, !tbaa !1
%tmp18 = load i32*, i32** %tmp17, align 8, !tbaa !1
%tmp19 = load i32, i32* %tmp18, align 4, !tbaa !8
%tmp20 = icmp ne i32 %tmp19, 0
br i1 %tmp20, label %bb28, label %bb21
bb21: ; preds = %bb13
%tmp22 = load i32, i32* bitcast ({ i8, i8, i8, i8, i8, i8, i8, i8 }* @g_320 to i32*), align 4
%tmp23 = ashr i32 %tmp22, 16
%tmp24 = icmp ne i32 %tmp23, 0
br i1 %tmp24, label %bb2, label %bb25
bb25: ; preds = %bb21
%tmp26 = load i16, i16* @g_225, align 2, !tbaa !6
%tmp27 = add i16 %tmp26, 1
store i16 %tmp27, i16* @g_225, align 2, !tbaa !6
br label %bb9
bb28: ; preds = %bb13, %bb9
ret void
}
; Function Attrs: nounwind
define dso_local void @func_33() #0 {
bb:
unreachable
}
; Function Attrs: nounwind
declare dso_local void @safe_sub_func_uint64_t_u_u() #0
attributes #0 = { nounwind "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="z13" "target-features"="+transactional-execution,+vector" "unsafe-fp-math"="false" "use-soft-float"="false" }
!llvm.ident = !{!0}
!0 = !{!"clang version 8.0.0 (http://llvm.org/git/clang.git a674a04e68bcf09f9a0423f3f589589596bc01a6) (http://llvm.org/git/llvm.git 1fe1ffe00e034128d1c5504254fdd4742f48bb9a)"}
!1 = !{!2, !2, i64 0}
!2 = !{!"any pointer", !3, i64 0}
!3 = !{!"omnipotent char", !4, i64 0}
!4 = !{!"Simple C/C++ TBAA"}
!5 = !{!3, !3, i64 0}
!6 = !{!7, !7, i64 0}
!7 = !{!"short", !3, i64 0}
!8 = !{!9, !9, i64 0}
!9 = !{!"int", !3, i64 0}