teak-llvm/llvm/test/Transforms/LoopFusion/simple.ll
Whitney Tsang 36bdc3dc35 [LoopFusion] Move instructions from FC0.Latch to FC1.Latch.
Summary:This PR move instructions from FC0.Latch bottom up to the
beginning of FC1.Latch as long as they are proven safe.

To illustrate why this is beneficial, let's consider the following
example:
Before Fusion:
header1:
  br header2
header2:
  br header2, latch1
latch1:
  br header1, preheader3
preheader3:
  br header3
header3:
  br header4
header4:
  br header4, latch3
latch3:
  br header3, exit3

After Fusion (before this PR):
header1:
  br header2
header2:
  br header2, latch1
latch1:
  br header3
header3:
  br header4
header4:
  br header4, latch3
latch3:
  br header1, exit3

Note that preheader3 is removed during fusion before this PR.
Notice that we cannot fuse loop2 with loop4 as there exists block latch1
in between.
This PR move instructions from latch1 to beginning of latch3, and remove
block latch1. LoopFusion is now able to fuse loop nest recursively.

After Fusion (after this PR):
header1:
  br header2
header2:
  br header3
header3:
  br header4
header4:
  br header2, latch3
latch3:
  br header1, exit3

Reviewer: kbarton, jdoerfert, Meinersbur, dmgreen, fhahn, hfinkel,
bmahjour, etiotto
Reviewed By: kbarton, Meinersbur
Subscribers: hiraditya, llvm-commits
Tag: LLVM
Differential Revision: https://reviews.llvm.org/D71165
2019-12-17 22:10:23 +00:00

309 lines
11 KiB
LLVM

; RUN: opt -S -loop-fusion < %s | FileCheck %s
@B = common global [1024 x i32] zeroinitializer, align 16
; CHECK: void @dep_free
; CHECK-NEXT: bb:
; CHECK-NEXT: br label %[[LOOP1HEADER:bb[0-9]*]]
; CHECK: [[LOOP1HEADER]]
; CHECK: br label %[[LOOP2HEADER:bb[0-9]*]]
; CHECK: [[LOOP2HEADER]]
; CHECK: br label %[[LOOP2LATCH:bb[0-9]+]]
; CHECK: [[LOOP2LATCH]]
; CHECK: br i1 %{{.*}}, label %[[LOOP1HEADER]], label %{{.*}}
; CHECK: ret void
define void @dep_free(i32* noalias %arg) {
bb:
br label %bb7
bb7: ; preds = %bb, %bb14
%.014 = phi i32 [ 0, %bb ], [ %tmp15, %bb14 ]
%indvars.iv23 = phi i64 [ 0, %bb ], [ %indvars.iv.next3, %bb14 ]
%tmp = add nsw i32 %.014, -3
%tmp8 = add nuw nsw i64 %indvars.iv23, 3
%tmp9 = trunc i64 %tmp8 to i32
%tmp10 = mul nsw i32 %tmp, %tmp9
%tmp11 = trunc i64 %indvars.iv23 to i32
%tmp12 = srem i32 %tmp10, %tmp11
%tmp13 = getelementptr inbounds i32, i32* %arg, i64 %indvars.iv23
store i32 %tmp12, i32* %tmp13, align 4
br label %bb14
bb14: ; preds = %bb7
%indvars.iv.next3 = add nuw nsw i64 %indvars.iv23, 1
%tmp15 = add nuw nsw i32 %.014, 1
%exitcond4 = icmp ne i64 %indvars.iv.next3, 100
br i1 %exitcond4, label %bb7, label %bb17.preheader
bb17.preheader: ; preds = %bb14
br label %bb19
bb19: ; preds = %bb17.preheader, %bb27
%.02 = phi i32 [ 0, %bb17.preheader ], [ %tmp28, %bb27 ]
%indvars.iv1 = phi i64 [ 0, %bb17.preheader ], [ %indvars.iv.next, %bb27 ]
%tmp20 = add nsw i32 %.02, -3
%tmp21 = add nuw nsw i64 %indvars.iv1, 3
%tmp22 = trunc i64 %tmp21 to i32
%tmp23 = mul nsw i32 %tmp20, %tmp22
%tmp24 = trunc i64 %indvars.iv1 to i32
%tmp25 = srem i32 %tmp23, %tmp24
%tmp26 = getelementptr inbounds [1024 x i32], [1024 x i32]* @B, i64 0, i64 %indvars.iv1
store i32 %tmp25, i32* %tmp26, align 4
br label %bb27
bb27: ; preds = %bb19
%indvars.iv.next = add nuw nsw i64 %indvars.iv1, 1
%tmp28 = add nuw nsw i32 %.02, 1
%exitcond = icmp ne i64 %indvars.iv.next, 100
br i1 %exitcond, label %bb19, label %bb18
bb18: ; preds = %bb27
br label %bb29
bb29: ; preds = %bb18
ret void
}
; CHECK: void @dep_free_parametric
; CHECK-NEXT: bb:
; CHECK: br i1 %{{.*}}, label %[[LOOP1PREHEADER:bb[0-9.a-z]*]], label %[[EXITBLOCK:bb[0-9]*]]
; CHECK: [[LOOP1PREHEADER]]
; CHECK: br label %[[LOOP1HEADER:bb[0-9]*]]
; CHECK: [[LOOP1HEADER]]
; CHECK: br label %[[LOOP2HEADER:bb[0-9]*]]
; CHECK: [[LOOP2HEADER]]
; CHECK: br label %[[LOOP2LATCH:bb[0-9]+]]
; CHECK: [[LOOP2LATCH]]
; CHECK: br i1 %{{.*}}, label %[[LOOP1HEADER]], label %[[EXITBLOCK]]
; CHECK: ret void
define void @dep_free_parametric(i32* noalias %arg, i64 %arg2) {
bb:
%tmp3 = icmp slt i64 0, %arg2
br i1 %tmp3, label %bb5, label %bb15.preheader
bb5: ; preds = %bb5, %bb12
%.014 = phi i64 [ 0, %bb ], [ %tmp13, %bb12 ]
%tmp6 = add nsw i64 %.014, -3
%tmp7 = add nuw nsw i64 %.014, 3
%tmp8 = mul nsw i64 %tmp6, %tmp7
%tmp9 = srem i64 %tmp8, %.014
%tmp10 = trunc i64 %tmp9 to i32
%tmp11 = getelementptr inbounds i32, i32* %arg, i64 %.014
store i32 %tmp10, i32* %tmp11, align 4
br label %bb12
bb12: ; preds = %bb5
%tmp13 = add nuw nsw i64 %.014, 1
%tmp = icmp slt i64 %tmp13, %arg2
br i1 %tmp, label %bb5, label %bb15.preheader
bb15.preheader: ; preds = %bb12, %bb
%tmp161 = icmp slt i64 0, %arg2
br i1 %tmp161, label %bb18, label %bb27
bb18: ; preds = %bb15.preheader, %bb25
%.02 = phi i64 [ 0, %bb15.preheader ], [ %tmp26, %bb25 ]
%tmp19 = add nsw i64 %.02, -3
%tmp20 = add nuw nsw i64 %.02, 3
%tmp21 = mul nsw i64 %tmp19, %tmp20
%tmp22 = srem i64 %tmp21, %.02
%tmp23 = trunc i64 %tmp22 to i32
%tmp24 = getelementptr inbounds [1024 x i32], [1024 x i32]* @B, i64 0, i64 %.02
store i32 %tmp23, i32* %tmp24, align 4
br label %bb25
bb25: ; preds = %bb18
%tmp26 = add nuw nsw i64 %.02, 1
%tmp16 = icmp slt i64 %tmp26, %arg2
br i1 %tmp16, label %bb18, label %bb27
bb27: ; preds = %bb17
ret void
}
; CHECK: void @raw_only
; CHECK-NEXT: bb:
; CHECK-NEXT: br label %[[LOOP1HEADER:bb[0-9]*]]
; CHECK: [[LOOP1HEADER]]
; CHECK: br label %[[LOOP2HEADER:bb[0-9]*]]
; CHECK: [[LOOP2HEADER]]
; CHECK: br label %[[LOOP2LATCH:bb[0-9]+]]
; CHECK: [[LOOP2LATCH]]
; CHECK: br i1 %{{.*}}, label %[[LOOP1HEADER]], label %{{.*}}
; CHECK: ret void
define void @raw_only(i32* noalias %arg) {
bb:
br label %bb7
bb11.preheader: ; preds = %bb9
br label %bb13
bb7: ; preds = %bb, %bb9
%indvars.iv22 = phi i64 [ 0, %bb ], [ %indvars.iv.next3, %bb9 ]
%tmp = getelementptr inbounds i32, i32* %arg, i64 %indvars.iv22
%tmp8 = trunc i64 %indvars.iv22 to i32
store i32 %tmp8, i32* %tmp, align 4
br label %bb9
bb9: ; preds = %bb7
%indvars.iv.next3 = add nuw nsw i64 %indvars.iv22, 1
%exitcond4 = icmp ne i64 %indvars.iv.next3, 100
br i1 %exitcond4, label %bb7, label %bb11.preheader
bb13: ; preds = %bb11.preheader, %bb18
%indvars.iv1 = phi i64 [ 0, %bb11.preheader ], [ %indvars.iv.next, %bb18 ]
%tmp14 = getelementptr inbounds i32, i32* %arg, i64 %indvars.iv1
%tmp15 = load i32, i32* %tmp14, align 4
%tmp16 = shl nsw i32 %tmp15, 1
%tmp17 = getelementptr inbounds [1024 x i32], [1024 x i32]* @B, i64 0, i64 %indvars.iv1
store i32 %tmp16, i32* %tmp17, align 4
br label %bb18
bb18: ; preds = %bb13
%indvars.iv.next = add nuw nsw i64 %indvars.iv1, 1
%exitcond = icmp ne i64 %indvars.iv.next, 100 br i1 %exitcond, label %bb13, label %bb19
bb19: ; preds = %bb18
ret void
}
; CHECK: void @raw_only_parametric
; CHECK-NEXT: bb:
; CHECK: br i1 %{{.*}}, label %[[LOOP1PREHEADER:bb[0-9.a-z]*]], label %[[EXITBLOCK:bb[0-9]*]]
; CHECK: [[LOOP1PREHEADER]]
; CHECK: br label %[[LOOP1HEADER:bb[0-9]*]]
; CHECK: [[LOOP1HEADER]]
; CHECK: br i1 %{{.*}}, label %[[LOOP1HEADER]], label %[[EXITBLOCK]]
; CHECK: ret void
define void @raw_only_parametric(i32* noalias %arg, i32 %arg4) {
bb:
%tmp = sext i32 %arg4 to i64
%tmp64 = icmp sgt i32 %arg4, 0
br i1 %tmp64, label %bb8, label %bb23
bb8: ; preds = %bb, %bb8
%indvars.iv25 = phi i64 [ %indvars.iv.next3, %bb8 ], [ 0, %bb ]
%tmp9 = getelementptr inbounds i32, i32* %arg, i64 %indvars.iv25
%tmp10 = trunc i64 %indvars.iv25 to i32
store i32 %tmp10, i32* %tmp9, align 4
%indvars.iv.next3 = add nuw nsw i64 %indvars.iv25, 1
%tmp6 = icmp slt i64 %indvars.iv.next3, %tmp
br i1 %tmp6, label %bb8, label %bb17
bb17: ; preds = %bb8, %bb17
%indvars.iv3 = phi i64 [ %indvars.iv.next, %bb17 ], [ 0, %bb8 ]
%tmp18 = getelementptr inbounds i32, i32* %arg, i64 %indvars.iv3
%tmp19 = load i32, i32* %tmp18, align 4
%tmp20 = shl nsw i32 %tmp19, 1
%tmp21 = getelementptr inbounds [1024 x i32], [1024 x i32]* @B, i64 0, i64 %indvars.iv3
store i32 %tmp20, i32* %tmp21, align 4
%indvars.iv.next = add nuw nsw i64 %indvars.iv3, 1
%tmp15 = icmp slt i64 %indvars.iv.next, %tmp
br i1 %tmp15, label %bb17, label %bb23
bb23: ; preds = %bb17, %bb
ret void
}
; CHECK: void @forward_dep
; CHECK-NEXT: bb:
; CHECK: br label %[[LOOP1HEADER:bb[0-9]*]]
; CHECK: [[LOOP1HEADER]]
; CHECK: br label %[[LOOP2HEADER:bb[0-9]*]]
; CHECK: [[LOOP2HEADER]]
; CHECK: br label %[[LOOP2LATCH:bb[0-9]+]]
; CHECK: [[LOOP2LATCH]]
; CHECK: br i1 %{{.*}}, label %[[LOOP1HEADER]], label %{{.*}}
; CHECK: ret void
define void @forward_dep(i32* noalias %arg) {
bb:
br label %bb7
bb7: ; preds = %bb, %bb14
%.013 = phi i32 [ 0, %bb ], [ %tmp15, %bb14 ]
%indvars.iv22 = phi i64 [ 0, %bb ], [ %indvars.iv.next3, %bb14 ]
%tmp = add nsw i32 %.013, -3
%tmp8 = add nuw nsw i64 %indvars.iv22, 3
%tmp9 = trunc i64 %tmp8 to i32
%tmp10 = mul nsw i32 %tmp, %tmp9
%tmp11 = trunc i64 %indvars.iv22 to i32
%tmp12 = srem i32 %tmp10, %tmp11
%tmp13 = getelementptr inbounds i32, i32* %arg, i64 %indvars.iv22
store i32 %tmp12, i32* %tmp13, align 4
br label %bb14
bb14: ; preds = %bb7
%indvars.iv.next3 = add nuw nsw i64 %indvars.iv22, 1
%tmp15 = add nuw nsw i32 %.013, 1
%exitcond4 = icmp ne i64 %indvars.iv.next3, 100
br i1 %exitcond4, label %bb7, label %bb19
bb19: ; preds = %bb14, %bb25
%indvars.iv1 = phi i64 [ 0, %bb14 ], [ %indvars.iv.next, %bb25 ]
%tmp20 = add nsw i64 %indvars.iv1, -3
%tmp21 = getelementptr inbounds i32, i32* %arg, i64 %tmp20
%tmp22 = load i32, i32* %tmp21, align 4
%tmp23 = mul nsw i32 %tmp22, 3
%tmp24 = getelementptr inbounds i32, i32* %arg, i64 %indvars.iv1
store i32 %tmp23, i32* %tmp24, align 4
br label %bb25
bb25: ; preds = %bb19
%indvars.iv.next = add nuw nsw i64 %indvars.iv1, 1
%exitcond = icmp ne i64 %indvars.iv.next, 100
br i1 %exitcond, label %bb19, label %bb26
bb26: ; preds = %bb25
ret void
}
; Test that instructions in loop 1 latch are moved to the beginning of loop 2
; latch iff it is proven safe. %inc.first and %cmp.first are moved, but
; `store i32 0, i32* %Ai.first` is not.
; CHECK: void @flow_dep
; CHECK-LABEL: entry:
; CHECK-NEXT: br label %for.first
; CHECK-LABEL: for.first:
; CHECK: store i32 0, i32* %Ai.first
; CHECK: %Ai.second =
; CHECK: br label %for.second.latch
; CHECK-LABEL: for.second.latch:
; CHECK-NEXT: %inc.first = add nsw i64 %i.first, 1
; CHECK-NEXT: %cmp.first = icmp slt i64 %inc.first, 100
; CHECK: br i1 %cmp.second, label %for.first, label %for.end
; CHECK-LABEL: for.end:
; CHECK-NEXT: ret void
define void @flow_dep(i32* noalias %A, i32* noalias %B) {
entry:
br label %for.first
for.first:
%i.first = phi i64 [ 0, %entry ], [ %inc.first, %for.first ]
%Ai.first = getelementptr inbounds i32, i32* %A, i64 %i.first
store i32 0, i32* %Ai.first, align 4
%inc.first = add nsw i64 %i.first, 1
%cmp.first = icmp slt i64 %inc.first, 100
br i1 %cmp.first, label %for.first, label %for.second.preheader
for.second.preheader:
br label %for.second
for.second:
%i.second = phi i64 [ %inc.second, %for.second.latch ], [ 0, %for.second.preheader ]
%Ai.second = getelementptr inbounds i32, i32* %A, i64 %i.second
%0 = load i32, i32* %Ai.second, align 4
%Bi = getelementptr inbounds i32, i32* %B, i64 %i.second
store i32 %0, i32* %Bi, align 4
br label %for.second.latch
for.second.latch:
%inc.second = add nsw i64 %i.second, 1
%cmp.second = icmp slt i64 %inc.second, 100
br i1 %cmp.second, label %for.second, label %for.end
for.end:
ret void
}