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Author SHA1 Message Date
Jon Roelofs 4b19e7dfae [LoopIdiomRecognize][Remarks] Track loop-strided store to/from blocks 
Differential revision: https://reviews.llvm.org/D109929
 2021-09-16 15:46:26 -07:00
Han Zhu da1cdffbb1 [loop-idiom] Hoist loop memcpys to loop preheader 
For a simple loop like:
```
struct S {
  int x;
  int y;
  char b;
};

unsigned foo(S* __restrict__ a, S* b, int n) {
  for (int i = 0; i < n; i++)
    a[i] = b[i];

  return sizeof(a[0]);
}
```
We could eliminate the loop and convert it to a large memcpy of 12*n bytes. Currently this is not handled. Output of `opt -loop-idiom -S < memcpy_before.ll`
```
%struct.S = type { i32, i32, i8 }

define dso_local i32 @_Z3fooP1SS0_i(%struct.S* noalias nocapture %a, %struct.S* nocapture readonly %b, i32 %n) local_unnamed_addr {
entry:
  %cmp7 = icmp sgt i32 %n, 0
  br i1 %cmp7, label %for.body.preheader, label %for.cond.cleanup

for.body.preheader:                               ; preds = %entry
  br label %for.body

for.cond.cleanup.loopexit:                        ; preds = %for.body
  br label %for.cond.cleanup

for.cond.cleanup:                                 ; preds = %for.cond.cleanup.loopexit, %entry
  ret i32 12

for.body:                                         ; preds = %for.body, %for.body.preheader
  %i.08 = phi i32 [ %inc, %for.body ], [ 0, %for.body.preheader ]
  %idxprom = zext i32 %i.08 to i64
  %arrayidx = getelementptr inbounds %struct.S, %struct.S* %b, i64 %idxprom
  %arrayidx2 = getelementptr inbounds %struct.S, %struct.S* %a, i64 %idxprom
  %0 = bitcast %struct.S* %arrayidx2 to i8*
  %1 = bitcast %struct.S* %arrayidx to i8*
  call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull align 4 dereferenceable(12) %0, i8* nonnull align 4 dereferenceable(12) %1, i64 12, i1 false)
  %inc = add nuw nsw i32 %i.08, 1
  %cmp = icmp slt i32 %inc, %n
  br i1 %cmp, label %for.body, label %for.cond.cleanup.loopexit
}

; Function Attrs: argmemonly nofree nosync nounwind willreturn
declare void @llvm.memcpy.p0i8.p0i8.i64(i8* noalias nocapture writeonly, i8* noalias nocapture readonly, i64, i1 immarg) #0

attributes #0 = { argmemonly nofree nosync nounwind willreturn }

```
The loop idiom pass currently only handles load and store instructions. Since struct S is too big to fit in a register, the loop body contains a memcpy intrinsic.

With this change, re-run `opt -loop-idiom -S < memcpy_before.ll`. The loop memcpy is promoted to loop preheader. For this trivial case, the loop is dead and will be removed by another pass.
```
%struct.S = type { i32, i32, i8 }

define dso_local i32 @_Z3fooP1SS0_i(%struct.S* noalias nocapture %a, %struct.S* nocapture readonly %b, i32 %n) local_unnamed_addr {
entry:
  %a1 = bitcast %struct.S* %a to i8*
  %b2 = bitcast %struct.S* %b to i8*
  %cmp7 = icmp sgt i32 %n, 0
  br i1 %cmp7, label %for.body.preheader, label %for.cond.cleanup

for.body.preheader:                               ; preds = %entry
  %0 = zext i32 %n to i64
  %1 = mul nuw nsw i64 %0, 12
  call void @llvm.memcpy.p0i8.p0i8.i64(i8* align 4 %a1, i8* align 4 %b2, i64 %1, i1 false)
  br label %for.body

for.cond.cleanup.loopexit:                        ; preds = %for.body
  br label %for.cond.cleanup

for.cond.cleanup:                                 ; preds = %for.cond.cleanup.loopexit, %entry
  ret i32 12

for.body:                                         ; preds = %for.body, %for.body.preheader
  %i.08 = phi i32 [ %inc, %for.body ], [ 0, %for.body.preheader ]
  %idxprom = zext i32 %i.08 to i64
  %arrayidx = getelementptr inbounds %struct.S, %struct.S* %b, i64 %idxprom
  %arrayidx2 = getelementptr inbounds %struct.S, %struct.S* %a, i64 %idxprom
  %2 = bitcast %struct.S* %arrayidx2 to i8*
  %3 = bitcast %struct.S* %arrayidx to i8*
  %inc = add nuw nsw i32 %i.08, 1
  %cmp = icmp slt i32 %inc, %n
  br i1 %cmp, label %for.body, label %for.cond.cleanup.loopexit
}

; Function Attrs: argmemonly nofree nosync nounwind willreturn
declare void @llvm.memcpy.p0i8.p0i8.i64(i8* noalias nocapture writeonly, i8* noalias nocapture readonly, i64, i1 immarg) #0

attributes #0 = { argmemonly nofree nosync nounwind willreturn }
```

Reviewed By: zino

Differential Revision: https://reviews.llvm.org/D97667
 2021-05-04 17:05:04 -07:00
Tres Popp efce19c3b0 Revert "[loop-idiom] Hoist loop memcpys to loop preheader" 
This reverts commit 75d6b8bb40.

The reasoning is mentioned in https://reviews.llvm.org/D97667
 2021-04-28 13:16:34 +02:00
Han Zhu 75d6b8bb40 [loop-idiom] Hoist loop memcpys to loop preheader 
For a simple loop like:
```
struct S {
  int x;
  int y;
  char b;
};

unsigned foo(S* __restrict__ a, S* b, int n) {
  for (int i = 0; i < n; i++)
    a[i] = b[i];

  return sizeof(a[0]);
}
```
We could eliminate the loop and convert it to a large memcpy of 12*n bytes. Currently this is not handled. Output of `opt -loop-idiom -S < memcpy_before.ll`
```
%struct.S = type { i32, i32, i8 }

define dso_local i32 @_Z3fooP1SS0_i(%struct.S* noalias nocapture %a, %struct.S* nocapture readonly %b, i32 %n) local_unnamed_addr {
entry:
  %cmp7 = icmp sgt i32 %n, 0
  br i1 %cmp7, label %for.body.preheader, label %for.cond.cleanup

for.body.preheader:                               ; preds = %entry
  br label %for.body

for.cond.cleanup.loopexit:                        ; preds = %for.body
  br label %for.cond.cleanup

for.cond.cleanup:                                 ; preds = %for.cond.cleanup.loopexit, %entry
  ret i32 12

for.body:                                         ; preds = %for.body, %for.body.preheader
  %i.08 = phi i32 [ %inc, %for.body ], [ 0, %for.body.preheader ]
  %idxprom = zext i32 %i.08 to i64
  %arrayidx = getelementptr inbounds %struct.S, %struct.S* %b, i64 %idxprom
  %arrayidx2 = getelementptr inbounds %struct.S, %struct.S* %a, i64 %idxprom
  %0 = bitcast %struct.S* %arrayidx2 to i8*
  %1 = bitcast %struct.S* %arrayidx to i8*
  call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull align 4 dereferenceable(12) %0, i8* nonnull align 4 dereferenceable(12) %1, i64 12, i1 false)
  %inc = add nuw nsw i32 %i.08, 1
  %cmp = icmp slt i32 %inc, %n
  br i1 %cmp, label %for.body, label %for.cond.cleanup.loopexit
}

; Function Attrs: argmemonly nofree nosync nounwind willreturn
declare void @llvm.memcpy.p0i8.p0i8.i64(i8* noalias nocapture writeonly, i8* noalias nocapture readonly, i64, i1 immarg) #0

attributes #0 = { argmemonly nofree nosync nounwind willreturn }

```
The loop idiom pass currently only handles load and store instructions. Since struct S is too big to fit in a register, the loop body contains a memcpy intrinsic.

With this change, re-run `opt -loop-idiom -S < memcpy_before.ll`. The loop memcpy is promoted to loop preheader. For this trivial case, the loop is dead and will be removed by another pass.
```
%struct.S = type { i32, i32, i8 }

define dso_local i32 @_Z3fooP1SS0_i(%struct.S* noalias nocapture %a, %struct.S* nocapture readonly %b, i32 %n) local_unnamed_addr {
entry:
  %a1 = bitcast %struct.S* %a to i8*
  %b2 = bitcast %struct.S* %b to i8*
  %cmp7 = icmp sgt i32 %n, 0
  br i1 %cmp7, label %for.body.preheader, label %for.cond.cleanup

for.body.preheader:                               ; preds = %entry
  %0 = zext i32 %n to i64
  %1 = mul nuw nsw i64 %0, 12
  call void @llvm.memcpy.p0i8.p0i8.i64(i8* align 4 %a1, i8* align 4 %b2, i64 %1, i1 false)
  br label %for.body

for.cond.cleanup.loopexit:                        ; preds = %for.body
  br label %for.cond.cleanup

for.cond.cleanup:                                 ; preds = %for.cond.cleanup.loopexit, %entry
  ret i32 12

for.body:                                         ; preds = %for.body, %for.body.preheader
  %i.08 = phi i32 [ %inc, %for.body ], [ 0, %for.body.preheader ]
  %idxprom = zext i32 %i.08 to i64
  %arrayidx = getelementptr inbounds %struct.S, %struct.S* %b, i64 %idxprom
  %arrayidx2 = getelementptr inbounds %struct.S, %struct.S* %a, i64 %idxprom
  %2 = bitcast %struct.S* %arrayidx2 to i8*
  %3 = bitcast %struct.S* %arrayidx to i8*
  %inc = add nuw nsw i32 %i.08, 1
  %cmp = icmp slt i32 %inc, %n
  br i1 %cmp, label %for.body, label %for.cond.cleanup.loopexit
}

; Function Attrs: argmemonly nofree nosync nounwind willreturn
declare void @llvm.memcpy.p0i8.p0i8.i64(i8* noalias nocapture writeonly, i8* noalias nocapture readonly, i64, i1 immarg) #0

attributes #0 = { argmemonly nofree nosync nounwind willreturn }
```

Reviewed By: zino

Differential Revision: https://reviews.llvm.org/D97667
 2021-04-27 17:37:51 -07:00
Krasimir Georgiev 8e7df996e3 Revert "[loop-idiom] Hoist loop memcpys to loop preheader" 
This reverts commit 92ddd3c1b6.

Causes multistage clang crashes, e.g.:
https://lab.llvm.org/buildbot/#/builders/36/builds/6678
 2021-03-30 11:47:12 +02:00
Han Zhu 92ddd3c1b6 [loop-idiom] Hoist loop memcpys to loop preheader 
For a simple loop like:
```
struct S {
  int x;
  int y;
  char b;
};

unsigned foo(S* __restrict__ a, S* b, int n) {
  for (int i = 0; i < n; i++)
    a[i] = b[i];

  return sizeof(a[0]);
}
```
We could eliminate the loop and convert it to a large memcpy of 12*n bytes. Currently this is not handled. Output of `opt -loop-idiom -S < memcpy_before.ll`
```
%struct.S = type { i32, i32, i8 }

define dso_local i32 @_Z3fooP1SS0_i(%struct.S* noalias nocapture %a, %struct.S* nocapture readonly %b, i32 %n) local_unnamed_addr {
entry:
  %cmp7 = icmp sgt i32 %n, 0
  br i1 %cmp7, label %for.body.preheader, label %for.cond.cleanup

for.body.preheader:                               ; preds = %entry
  br label %for.body

for.cond.cleanup.loopexit:                        ; preds = %for.body
  br label %for.cond.cleanup

for.cond.cleanup:                                 ; preds = %for.cond.cleanup.loopexit, %entry
  ret i32 12

for.body:                                         ; preds = %for.body, %for.body.preheader
  %i.08 = phi i32 [ %inc, %for.body ], [ 0, %for.body.preheader ]
  %idxprom = zext i32 %i.08 to i64
  %arrayidx = getelementptr inbounds %struct.S, %struct.S* %b, i64 %idxprom
  %arrayidx2 = getelementptr inbounds %struct.S, %struct.S* %a, i64 %idxprom
  %0 = bitcast %struct.S* %arrayidx2 to i8*
  %1 = bitcast %struct.S* %arrayidx to i8*
  call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull align 4 dereferenceable(12) %0, i8* nonnull align 4 dereferenceable(12) %1, i64 12, i1 false)
  %inc = add nuw nsw i32 %i.08, 1
  %cmp = icmp slt i32 %inc, %n
  br i1 %cmp, label %for.body, label %for.cond.cleanup.loopexit
}

; Function Attrs: argmemonly nofree nosync nounwind willreturn
declare void @llvm.memcpy.p0i8.p0i8.i64(i8* noalias nocapture writeonly, i8* noalias nocapture readonly, i64, i1 immarg) #0

attributes #0 = { argmemonly nofree nosync nounwind willreturn }

```
The loop idiom pass currently only handles load and store instructions. Since struct S is too big to fit in a register, the loop body contains a memcpy intrinsic.

With this change, re-run `opt -loop-idiom -S < memcpy_before.ll`. The loop memcpy is promoted to loop preheader. For this trivial case, the loop is dead and will be removed by another pass.
```
%struct.S = type { i32, i32, i8 }

define dso_local i32 @_Z3fooP1SS0_i(%struct.S* noalias nocapture %a, %struct.S* nocapture readonly %b, i32 %n) local_unnamed_addr {
entry:
  %a1 = bitcast %struct.S* %a to i8*
  %b2 = bitcast %struct.S* %b to i8*
  %cmp7 = icmp sgt i32 %n, 0
  br i1 %cmp7, label %for.body.preheader, label %for.cond.cleanup

for.body.preheader:                               ; preds = %entry
  %0 = zext i32 %n to i64
  %1 = mul nuw nsw i64 %0, 12
  call void @llvm.memcpy.p0i8.p0i8.i64(i8* align 4 %a1, i8* align 4 %b2, i64 %1, i1 false)
  br label %for.body

for.cond.cleanup.loopexit:                        ; preds = %for.body
  br label %for.cond.cleanup

for.cond.cleanup:                                 ; preds = %for.cond.cleanup.loopexit, %entry
  ret i32 12

for.body:                                         ; preds = %for.body, %for.body.preheader
  %i.08 = phi i32 [ %inc, %for.body ], [ 0, %for.body.preheader ]
  %idxprom = zext i32 %i.08 to i64
  %arrayidx = getelementptr inbounds %struct.S, %struct.S* %b, i64 %idxprom
  %arrayidx2 = getelementptr inbounds %struct.S, %struct.S* %a, i64 %idxprom
  %2 = bitcast %struct.S* %arrayidx2 to i8*
  %3 = bitcast %struct.S* %arrayidx to i8*
  %inc = add nuw nsw i32 %i.08, 1
  %cmp = icmp slt i32 %inc, %n
  br i1 %cmp, label %for.body, label %for.cond.cleanup.loopexit
}

; Function Attrs: argmemonly nofree nosync nounwind willreturn
declare void @llvm.memcpy.p0i8.p0i8.i64(i8* noalias nocapture writeonly, i8* noalias nocapture readonly, i64, i1 immarg) #0

attributes #0 = { argmemonly nofree nosync nounwind willreturn }
```

Reviewed By: zino

Differential Revision: https://reviews.llvm.org/D97667
 2021-03-29 23:36:26 -07:00
Han Zhu 2bd4049ceb Revert "[loop-idiom] Hoist loop memcpys to loop preheader" 
This reverts commit deb5095833.

Bad commit message.
 2021-03-29 23:35:35 -07:00
Han Zhu deb5095833 [loop-idiom] Hoist loop memcpys to loop preheader 
Summary:

Test Plan:

Reviewers:

Subscribers:

Tasks:

Tags:

Blame Revision:

Differential Revision: https://phabricator.intern.facebook.com/D26380397
 2021-03-29 23:14:42 -07:00
Fangrui Song f31811f2dc [BasicAA] Rename deprecated -basicaa to -basic-aa 
Follow-up to D82607
Revert an accidental change (empty.ll) of D82683
 2020-06-26 20:41:37 -07:00
Sam Parker 60d6fb2a63 [SCEV] Use NoWrapFlags when expanding a simple mul 
Second functional change following on from rL362687. Pass the
NoWrapFlags from the MulExpr to InsertBinop when we're generating a
shl or mul.

Differential Revision: https://reviews.llvm.org/D61934

llvm-svn: 363540
 2019-06-17 10:05:18 +00:00
Benjamin Kramer f1249442cf Revert "[SCEV] Use wrap flags in InsertBinop" 
This reverts commit r362687. Miscompiles llvm-profdata during selfhost.

llvm-svn: 362699
 2019-06-06 12:35:46 +00:00
Sam Parker 7cc580f5e9 [SCEV] Use wrap flags in InsertBinop 
If the given SCEVExpr has no (un)signed flags attached to it, transfer
these to the resulting instruction or use them to find an existing
instruction.

Differential Revision: https://reviews.llvm.org/D61934

llvm-svn: 362687
 2019-06-06 08:56:26 +00:00
Roman Lebedev e8578953ac [LoopIdiom] Basic OptimizationRemarkEmitter handling 
Summary:
I'm adding ORE to memset/memcpy formation, with tests,
but mainly this is split off from D61144.

Reviewers: reames, anemet, thegameg, craig.topper

Reviewed By: thegameg

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62631

llvm-svn: 362092
 2019-05-30 13:02:06 +00:00