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Enable loopreroll for sext of loop control only IV 

This patch extend loopreroll to allow the instruction chain
    of loop control only IV has sext.

llvm-svn: 269084
This commit is contained in:
Lawrence Hu 2016-05-10 17:42:27 +00:00
parent 2e64438ae4
commit 8cc3b37d2c
2 changed files with 219 additions and 12 deletions
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45
llvm/lib/Transforms/Scalar/LoopRerollPass.cpp
View File

@ -512,11 +512,11 @@ static const SCEVConstant *getIncrmentFactorSCEV(ScalarEvolution *SE,
// Check if an IV is only used to control the loop. There are two cases:
// 1. It only has one use which is loop increment, and the increment is only
// used by comparison and the PHI, and the comparison is only used by branch.
// used by comparison and the PHI (could has sext with nsw in between), and the
// comparison is only used by branch.
// 2. It is used by loop increment and the comparison, the loop increment is
// only used by the PHI, and the comparison is used only by the branch.
bool LoopReroll::isLoopControlIV(Loop *L, Instruction *IV) {
unsigned IVUses = IV->getNumUses();
if (IVUses != 2 && IVUses != 1)
return false;
@ -551,9 +551,17 @@ bool LoopReroll::isLoopControlIV(Loop *L, Instruction *IV) {
if (PN != IV)
return false;
}
// Must be a CMP
else if (!isCompareUsedByBranch(dyn_cast<Instruction>(UU)))
return false;
// Must be a CMP or an ext (of a value with nsw) then CMP
else {
Instruction *UUser = dyn_cast<Instruction>(UU);
// Skip SExt if we are extending an nsw value
// TODO: Allow ZExt too
if (BO->hasNoSignedWrap() && UUser && UUser->getNumUses() == 1 &&
isa<SExtInst>(UUser))
UUser = dyn_cast<Instruction>(*(UUser->user_begin()));
if (!isCompareUsedByBranch(UUser))
return false;
}
}
} else
return false;
@ -1161,6 +1169,11 @@ bool LoopReroll::DAGRootTracker::validate(ReductionTracker &Reductions) {
Instruction *UUser = dyn_cast<Instruction>(UU);
// UUser could be compare, PHI or branch
Uses[UUser].set(IL_All);
// Skip SExt
if (isa<SExtInst>(UUser)) {
UUser = dyn_cast<Instruction>(*(UUser->user_begin()));
Uses[UUser].set(IL_All);
}
// Is UUser a compare instruction?
if (UU->hasOneUse()) {
Instruction *BI = dyn_cast<BranchInst>(*UUser->user_begin());
@ -1502,8 +1515,6 @@ void LoopReroll::DAGRootTracker::replaceIV(Instruction *Inst,
if (NeedNewIV)
ICSCEV = SE->getMulExpr(IterCount,
SE->getConstant(IterCount->getType(), Scale));
else
ICSCEV = RealIVSCEV->evaluateAtIteration(IterCount, *SE);
// Iteration count SCEV minus or plus 1
const SCEV *MinusPlus1SCEV =
@ -1515,18 +1526,26 @@ void LoopReroll::DAGRootTracker::replaceIV(Instruction *Inst,
const SCEV *ICMinusPlus1SCEV = SE->getMinusSCEV(ICSCEV, MinusPlus1SCEV);
// Iteration count minus 1
Value *ICMinusPlus1 = nullptr;
Instruction *InsertPtr = nullptr;
if (isa<SCEVConstant>(ICMinusPlus1SCEV)) {
ICMinusPlus1 =
Expander.expandCodeFor(ICMinusPlus1SCEV, NewIV->getType(), BI);
InsertPtr = BI;
} else {
BasicBlock *Preheader = L->getLoopPreheader();
if (!Preheader)
Preheader = InsertPreheaderForLoop(L, DT, LI, PreserveLCSSA);
ICMinusPlus1 = Expander.expandCodeFor(
ICMinusPlus1SCEV, NewIV->getType(), Preheader->getTerminator());
InsertPtr = Preheader->getTerminator();
}
if (!isa<PointerType>(NewIV->getType()) && NeedNewIV &&
(SE->getTypeSizeInBits(NewIV->getType()) <
SE->getTypeSizeInBits(ICMinusPlus1SCEV->getType()))) {
IRBuilder<> Builder(BI);
Builder.SetCurrentDebugLocation(BI->getDebugLoc());
NewIV = Builder.CreateSExt(NewIV, ICMinusPlus1SCEV->getType());
}
Value *ICMinusPlus1 = Expander.expandCodeFor(
ICMinusPlus1SCEV, NewIV->getType(), InsertPtr);
Value *Cond =
new ICmpInst(BI, CmpInst::ICMP_EQ, NewIV, ICMinusPlus1, "exitcond");
BI->setCondition(Cond);
@ -1705,6 +1724,7 @@ bool LoopReroll::runOnLoop(Loop *L, LPPassManager &LPM) {
const SCEV *LIBETC = SE->getBackedgeTakenCount(L);
const SCEV *IterCount = SE->getAddExpr(LIBETC, SE->getOne(LIBETC->getType()));
DEBUG(dbgs() << "\n Before Reroll:\n" << *(L->getHeader()) << "\n");
DEBUG(dbgs() << "LRR: iteration count = " << *IterCount << "\n");
// First, we need to find the induction variable with respect to which we can
@ -1731,6 +1751,7 @@ bool LoopReroll::runOnLoop(Loop *L, LPPassManager &LPM) {
Changed = true;
break;
}
DEBUG(dbgs() << "\n After Reroll:\n" << *(L->getHeader()) << "\n");
// Trip count of L has changed so SE must be re-evaluated.
if (Changed)

186
llvm/test/Transforms/LoopReroll/indvar_with_ext.ll Normal file
View File

@ -0,0 +1,186 @@
; RUN: opt -S -loop-reroll %s | FileCheck %s
target triple = "aarch64--linux-gnu"
define void @test(i32 %n, float* %arrayidx200, float* %arrayidx164, float* %arrayidx172) {
entry:
%rem.i = srem i32 %n, 4
%t22 = load float, float* %arrayidx172, align 4
%cmp.9 = icmp eq i32 %n, 0
%t7 = sext i32 %n to i64
br i1 %cmp.9, label %while.end, label %while.body.preheader
while.body.preheader:
br label %while.body
while.body:
;CHECK-LABEL: while.body:
;CHECK-NEXT: %indvars.iv.i423 = phi i64 [ %indvars.iv.next.i424, %while.body ], [ 0, %while.body.preheader ]
;CHECK-NEXT: [[T1:%[0-9]+]] = trunc i64 %indvars.iv.i423 to i32
;CHECK-NEXT: %arrayidx62.i = getelementptr inbounds float, float* %arrayidx200, i64 %indvars.iv.i423
;CHECK-NEXT: %t1 = load float, float* %arrayidx62.i, align 4
;CHECK-NEXT: %arrayidx64.i = getelementptr inbounds float, float* %arrayidx164, i64 %indvars.iv.i423
;CHECK-NEXT: %t2 = load float, float* %arrayidx64.i, align 4
;CHECK-NEXT: %mul65.i = fmul fast float %t2, %t22
;CHECK-NEXT: %add66.i = fadd fast float %mul65.i, %t1
;CHECK-NEXT: store float %add66.i, float* %arrayidx62.i, align 4
;CHECK-NEXT: %indvars.iv.next.i424 = add i64 %indvars.iv.i423, 1
;CHECK-NEXT: [[T2:%[0-9]+]] = sext i32 [[T1]] to i64
;CHECK-NEXT: %exitcond = icmp eq i64 [[T2]], %{{[0-9]+}}
;CHECK-NEXT: br i1 %exitcond, label %while.end.loopexit, label %while.body
%indvars.iv.i423 = phi i64 [ %indvars.iv.next.i424, %while.body ], [ 0, %while.body.preheader ]
%i.22.i = phi i32 [ %add103.i, %while.body ], [ %rem.i, %while.body.preheader ]
%arrayidx62.i = getelementptr inbounds float, float* %arrayidx200, i64 %indvars.iv.i423
%t1 = load float, float* %arrayidx62.i, align 4
%arrayidx64.i = getelementptr inbounds float, float* %arrayidx164, i64 %indvars.iv.i423
%t2 = load float, float* %arrayidx64.i, align 4
%mul65.i = fmul fast float %t2, %t22
%add66.i = fadd fast float %mul65.i, %t1
store float %add66.i, float* %arrayidx62.i, align 4
%t3 = add nsw i64 %indvars.iv.i423, 1
%arrayidx71.i = getelementptr inbounds float, float* %arrayidx200, i64 %t3
%t4 = load float, float* %arrayidx71.i, align 4
%arrayidx74.i = getelementptr inbounds float, float* %arrayidx164, i64 %t3
%t5 = load float, float* %arrayidx74.i, align 4
%mul75.i = fmul fast float %t5, %t22
%add76.i = fadd fast float %mul75.i, %t4
store float %add76.i, float* %arrayidx71.i, align 4
%add103.i = add nsw i32 %i.22.i, 2
%t6 = sext i32 %add103.i to i64
%cmp58.i = icmp slt i64 %t6, %t7
%indvars.iv.next.i424 = add i64 %indvars.iv.i423, 2
br i1 %cmp58.i, label %while.body, label %while.end.loopexit
while.end.loopexit:
br label %while.end
while.end:
ret void
}
; Function Attrs: noinline norecurse nounwind
define i32 @test2(i64 %n, i32* nocapture %x, i32* nocapture readonly %y) {
entry:
%cmp18 = icmp sgt i64 %n, 0
br i1 %cmp18, label %for.body.preheader, label %for.end
for.body.preheader: ; preds = %entry
br label %for.body
for.body: ; preds = %for.body.preheader, %for.body
;CHECK: for.body:
;CHECK-NEXT: %indvar = phi i64 [ %indvar.next, %for.body ], [ 0, %for.body.preheader ]
;CHECK-NEXT: %arrayidx = getelementptr inbounds i32, i32* %y, i64 %indvar
;CHECK-NEXT: [[T1:%[0-9]+]] = load i32, i32* %arrayidx, align 4
;CHECK-NEXT: %arrayidx3 = getelementptr inbounds i32, i32* %x, i64 %indvar
;CHECK-NEXT: store i32 [[T1]], i32* %arrayidx3, align 4
;CHECK-NEXT: %indvar.next = add i64 %indvar, 1
;CHECK-NEXT: %exitcond = icmp eq i64 %indvar, %{{[0-9]+}}
;CHECK-NEXT: br i1 %exitcond, label %for.end.loopexit, label %for.body
%indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %for.body.preheader ]
%arrayidx = getelementptr inbounds i32, i32* %y, i64 %indvars.iv
%0 = load i32, i32* %arrayidx, align 4
%arrayidx3 = getelementptr inbounds i32, i32* %x, i64 %indvars.iv
store i32 %0, i32* %arrayidx3, align 4
%1 = or i64 %indvars.iv, 1
%arrayidx5 = getelementptr inbounds i32, i32* %y, i64 %1
%2 = load i32, i32* %arrayidx5, align 4
%arrayidx8 = getelementptr inbounds i32, i32* %x, i64 %1
store i32 %2, i32* %arrayidx8, align 4
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 2
%cmp = icmp slt i64 %indvars.iv.next, %n
br i1 %cmp, label %for.body, label %for.end.loopexit
for.end.loopexit: ; preds = %for.body
br label %for.end
for.end: ; preds = %for.end.loopexit, %entry
ret i32 0
}
; Function Attrs: noinline norecurse nounwind
define i32 @test3(i32 %n, i32* nocapture %x, i32* nocapture readonly %y) {
entry:
%cmp21 = icmp sgt i32 %n, 0
br i1 %cmp21, label %for.body.preheader, label %for.end
for.body.preheader: ; preds = %entry
br label %for.body
for.body: ; preds = %for.body.preheader, %for.body
;CHECK: for.body:
;CHECK: %add12 = add i8 %i.022, 2
;CHECK-NEXT: %conv = sext i8 %add12 to i32
;CHECK-NEXT: %cmp = icmp slt i32 %conv, %n
;CHECK-NEXT: br i1 %cmp, label %for.body, label %for.end.loopexit
%conv23 = phi i32 [ %conv, %for.body ], [ 0, %for.body.preheader ]
%i.022 = phi i8 [ %add12, %for.body ], [ 0, %for.body.preheader ]
%idxprom = sext i8 %i.022 to i64
%arrayidx = getelementptr inbounds i32, i32* %y, i64 %idxprom
%0 = load i32, i32* %arrayidx, align 4
%arrayidx3 = getelementptr inbounds i32, i32* %x, i64 %idxprom
store i32 %0, i32* %arrayidx3, align 4
%add = or i32 %conv23, 1
%idxprom5 = sext i32 %add to i64
%arrayidx6 = getelementptr inbounds i32, i32* %y, i64 %idxprom5
%1 = load i32, i32* %arrayidx6, align 4
%arrayidx10 = getelementptr inbounds i32, i32* %x, i64 %idxprom5
store i32 %1, i32* %arrayidx10, align 4
%add12 = add i8 %i.022, 2
%conv = sext i8 %add12 to i32
%cmp = icmp slt i32 %conv, %n
br i1 %cmp, label %for.body, label %for.end.loopexit
for.end.loopexit: ; preds = %for.body
br label %for.end
for.end: ; preds = %for.end.loopexit, %entry
ret i32 0
}
; Function Attrs: noinline norecurse nounwind
define i32 @test4(i64 %n, i32* nocapture %x, i32* nocapture readonly %y) {
entry:
%cmp18 = icmp eq i64 %n, 0
br i1 %cmp18, label %for.end, label %for.body.preheader
for.body.preheader: ; preds = %entry
br label %for.body
for.body: ; preds = %for.body.preheader, %for.body
;CHECK: for.body:
;CHECK-NEXT: %indvar = phi i64 [ %indvar.next, %for.body ], [ 0, %for.body.preheader ]
;CHECK-NEXT: %arrayidx = getelementptr inbounds i32, i32* %y, i64 %indvar
;CHECK-NEXT: [[T1:%[0-9]+]] = load i32, i32* %arrayidx, align 4
;CHECK-NEXT: %arrayidx3 = getelementptr inbounds i32, i32* %x, i64 %indvar
;CHECK-NEXT: store i32 [[T1]], i32* %arrayidx3, align 4
;CHECK-NEXT: %indvar.next = add i64 %indvar, 1
;CHECK-NEXT: %exitcond = icmp eq i64 %indvar, %{{[0-9]+}}
;CHECK-NEXT: br i1 %exitcond, label %for.end.loopexit, label %for.body
%indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %for.body.preheader ]
%arrayidx = getelementptr inbounds i32, i32* %y, i64 %indvars.iv
%0 = load i32, i32* %arrayidx, align 4
%arrayidx3 = getelementptr inbounds i32, i32* %x, i64 %indvars.iv
store i32 %0, i32* %arrayidx3, align 4
%1 = or i64 %indvars.iv, 1
%arrayidx5 = getelementptr inbounds i32, i32* %y, i64 %1
%2 = load i32, i32* %arrayidx5, align 4
%arrayidx8 = getelementptr inbounds i32, i32* %x, i64 %1
store i32 %2, i32* %arrayidx8, align 4
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 2
%cmp = icmp ult i64 %indvars.iv.next, %n
br i1 %cmp, label %for.body, label %for.end.loopexit
for.end.loopexit: ; preds = %for.body
br label %for.end
for.end: ; preds = %for.end.loopexit, %entry
ret i32 0
}