Commit df49eeda authored by Bill Wendling's avatar Bill Wendling
Browse files

Approved by Chris: 

$ svn merge -c 113057 https://llvm.org/svn/llvm-project/llvm/trunk
--- Merging r113057 into '.':
A    test/Transforms/LoopSimplify/preserve-scev.ll
U    lib/Transforms/Utils/LoopSimplify.cpp

llvm-svn: 113851
parent 19cad46f

llvm/lib/Transforms/Utils/LoopSimplify.cpp

+10 −1
Original line number Diff line number Diff line
@@ -46,6 +46,7 @@ 
#include "llvm/LLVMContext.h"

#include "llvm/Type.h"

#include "llvm/Analysis/AliasAnalysis.h"

#include "llvm/Analysis/ScalarEvolution.h"

#include "llvm/Analysis/Dominators.h"

#include "llvm/Analysis/LoopPass.h"

#include "llvm/Transforms/Utils/BasicBlockUtils.h"
@@ -71,6 +72,7 @@ namespace { 
    AliasAnalysis *AA;

    LoopInfo *LI;

    DominatorTree *DT;

    ScalarEvolution *SE;

    Loop *L;

    virtual bool runOnLoop(Loop *L, LPPassManager &LPM);
@@ -83,7 +85,7 @@ namespace { 
      AU.addPreserved<LoopInfo>();



      AU.addPreserved<AliasAnalysis>();

      AU.addPreserved("scalar-evolution");

      AU.addPreserved<ScalarEvolution>();

      AU.addPreservedID(BreakCriticalEdgesID);  // No critical edges added.

      AU.addPreserved<DominanceFrontier>();

      AU.addPreservedID(LCSSAID);
@@ -121,6 +123,7 @@ bool LoopSimplify::runOnLoop(Loop *l, LPPassManager &LPM) { 
  LI = &getAnalysis<LoopInfo>();

  AA = getAnalysisIfAvailable<AliasAnalysis>();

  DT = &getAnalysis<DominatorTree>();

  SE = getAnalysisIfAvailable<ScalarEvolution>();



  Changed |= ProcessLoop(L, LPM);
@@ -532,6 +535,12 @@ Loop *LoopSimplify::SeparateNestedLoop(Loop *L, LPPassManager &LPM) { 


  DEBUG(dbgs() << "LoopSimplify: Splitting out a new outer loop\n");



  // If ScalarEvolution is around and knows anything about values in

  // this loop, tell it to forget them, because we're about to

  // substantially change it.

  if (SE)

    SE->forgetLoop(L);



  BasicBlock *Header = L->getHeader();

  BasicBlock *NewBB = SplitBlockPredecessors(Header, &OuterLoopPreds[0],

                                             OuterLoopPreds.size(),

llvm/test/Transforms/LoopSimplify/preserve-scev.ll

0 → 100644
+50 −0
Original line number Diff line number Diff line 
; RUN: opt -S < %s -indvars | opt -analyze -iv-users | grep {%cmp = icmp slt i32} | grep {= \{%\\.ph,+,1\}<%for.cond>}

; PR8079



; LoopSimplify should invalidate indvars when splitting out the

; inner loop.



@maxStat = external global i32



define i32 @test() nounwind {

entry:

  br label %for.cond



for.cond:                                         ; preds = %if.then5, %if.end, %entry

  %cuts.1 = phi i32 [ 0, %entry ], [ %inc, %if.then5 ], [ %cuts.1, %if.end ]

  %0 = phi i32 [ 0, %entry ], [ %add, %if.end ], [ %add, %if.then5 ]

  %add = add i32 %0, 1

  %cmp = icmp slt i32 %0, 1

  %tmp1 = load i32* @maxStat, align 4

  br i1 %cmp, label %for.body, label %for.cond14.preheader



for.cond14.preheader:                             ; preds = %for.cond

  %cmp1726 = icmp sgt i32 %tmp1, 0

  br i1 %cmp1726, label %for.body18, label %return



for.body:                                         ; preds = %for.cond

  %cmp2 = icmp sgt i32 %tmp1, 100

  br i1 %cmp2, label %return, label %if.end



if.end:                                           ; preds = %for.body

  %cmp4 = icmp sgt i32 %tmp1, -1

  br i1 %cmp4, label %if.then5, label %for.cond



if.then5:                                         ; preds = %if.end

  call void @foo() nounwind

  %inc = add i32 %cuts.1, 1

  br label %for.cond



for.body18:                                       ; preds = %for.body18, %for.cond14.preheader

  %i13.027 = phi i32 [ %1, %for.body18 ], [ 0, %for.cond14.preheader ]

  call void @foo() nounwind

  %1 = add nsw i32 %i13.027, 1

  %tmp16 = load i32* @maxStat, align 4

  %cmp17 = icmp slt i32 %1, %tmp16

  br i1 %cmp17, label %for.body18, label %return



return:                                           ; preds = %for.body18, %for.body, %for.cond14.preheader

  ret i32 0

}



declare void @foo() nounwind