RPCS3/llvm
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm.git synced 2025-01-19 16:35:10 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Fix LoopSimplify to notify ScalarEvolution when splitting a loop backedge

Browse Source 
into an inner loop, as the new loop iteration may differ substantially.
This fixes PR8078.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113057 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2010-09-04 02:42:48 +00:00
parent aace0f295b
commit ffa75cdcf8
2 changed files with 60 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
lib/Transforms/Utils/LoopSimplify.cpp
View File

@ -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(),

50
test/Transforms/LoopSimplify/preserve-scev.ll Normal file
View File

@ -0,0 +1,50 @@
; 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