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llvm-project/llvm/test/Transforms/LoopFusion/guarded.ll

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[LoopFusion] Add ability to fuse guarded loops Summary: This patch extends the current capabilities in loop fusion to fuse guarded loops (as defined in https://reviews.llvm.org/D63885). The patch adds the necessary safety checks to ensure that it safe to fuse the guarded loops (control flow equivalent, no intervening code, and same guard conditions). It also provides an alternative method to perform the actual fusion of guarded loops. The mechanics to fuse guarded loops are slightly different then fusing non-guarded loops, so I opted to keep them separate methods. I will be cleaning this up in later patches, and hope to converge on a single method to fuse both guarded and non-guarded loops, but for now I think the review will be easier to keep them separate. Reviewers: jdoerfert, Meinersbur, dmgreen, etiotto, Whitney Subscribers: hiraditya, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D65464 llvm-svn: 373018
2019-09-27 05:42:45 +08:00
; RUN: opt -S -loop-fusion < %s | FileCheck %s
@B = common global [1024 x i32] zeroinitializer, align 16
; CHECK: void @dep_free_parametric
; CHECK-next: entry:
; CHECK: br i1 %{{.*}}, label %[[LOOP1PREHEADER:bb[0-9]*]], label %[[LOOP1SUCC:bb[0-9]+]]
; CHECK: [[LOOP1PREHEADER]]
; CHECK-NEXT: br label %[[LOOP1BODY:bb[0-9]*]]
; CHECK: [[LOOP1BODY]]
; CHECK: br i1 %{{.*}}, label %[[LOOP1BODY]], label %[[LOOP2EXIT:bb[0-9]+]]
; CHECK: [[LOOP2EXIT]]
; CHECK: br label %[[LOOP1SUCC]]
; CHECK: [[LOOP1SUCC]]
; CHECK: ret void
define void @dep_free_parametric(i32* noalias %A, i64 %N) {
entry:
%cmp4 = icmp slt i64 0, %N
br i1 %cmp4, label %bb3, label %bb14
bb3: ; preds = %entry
br label %bb5
bb5: ; preds = %bb3, %bb5
%i.05 = phi i64 [ %inc, %bb5 ], [ 0, %bb3 ]
%sub = sub nsw i64 %i.05, 3
%add = add nsw i64 %i.05, 3
%mul = mul nsw i64 %sub, %add
%rem = srem i64 %mul, %i.05
%conv = trunc i64 %rem to i32
%arrayidx = getelementptr inbounds i32, i32* %A, i64 %i.05
store i32 %conv, i32* %arrayidx, align 4
%inc = add nsw i64 %i.05, 1
%cmp = icmp slt i64 %inc, %N
br i1 %cmp, label %bb5, label %bb10
bb10: ; preds = %bb5
br label %bb14
bb14: ; preds = %bb10, %entry
%cmp31 = icmp slt i64 0, %N
br i1 %cmp31, label %bb8, label %bb12
bb8: ; preds = %bb14
br label %bb9
bb9: ; preds = %bb8, %bb9
%i1.02 = phi i64 [ %inc14, %bb9 ], [ 0, %bb8 ]
%sub7 = sub nsw i64 %i1.02, 3
%add8 = add nsw i64 %i1.02, 3
%mul9 = mul nsw i64 %sub7, %add8
%rem10 = srem i64 %mul9, %i1.02
%conv11 = trunc i64 %rem10 to i32
%arrayidx12 = getelementptr inbounds [1024 x i32], [1024 x i32]* @B, i64 0, i64 %i1.02
store i32 %conv11, i32* %arrayidx12, align 4
%inc14 = add nsw i64 %i1.02, 1
%cmp3 = icmp slt i64 %inc14, %N
br i1 %cmp3, label %bb9, label %bb15
bb15: ; preds = %bb9
br label %bb12
bb12: ; preds = %bb15, %bb14
ret void
}
[LoopFusion] Move instructions from FC1.Preheader to FC0.Preheader when proven safe. Summary: Currently LoopFusion give up when the second loop nest preheader is not empty. For example: for (int i = 0; i < 100; ++i) {} x+=1; for (int i = 0; i < 100; ++i) {} The above example should be safe to fuse. This PR moves instructions in FC1 preheader (e.g. x+=1; ) to FC0 preheader, which then LoopFusion is able to fuse them. Reviewer: kbarton, Meinersbur, jdoerfert, dmgreen, fhahn, hfinkel, bmahjour, etiotto Reviewed By: jdoerfert Subscribers: hiraditya, llvm-commits Tag: LLVM Differential Revision: https://reviews.llvm.org/D71821
2020-01-29 23:02:21 +08:00
; Test that `%add` is moved in for.first.preheader, and the two loops for.first
; and for.second are fused.
; CHECK: void @moveinsts_preheader
; CHECK-LABEL: for.first.guard:
; CHECK: br i1 %cmp.guard, label %for.first.preheader, label %for.end
; CHECK-LABEL: for.first.preheader:
; CHECK-NEXT: %add = add nsw i32 %x, 1
; CHECK-NEXT: br label %for.first
; CHECK-LABEL: for.first:
; CHECK: br i1 %cmp.j, label %for.first, label %for.second.exit
; CHECK-LABEL: for.second.exit:
; CHECK-NEXT: br label %for.end
; CHECK-LABEL: for.end:
; CHECK-NEXT: ret void
define void @moveinsts_preheader(i32* noalias %A, i32* noalias %B, i64 %N, i32 %x) {
for.first.guard:
%cmp.guard = icmp slt i64 0, %N
br i1 %cmp.guard, label %for.first.preheader, label %for.second.guard
for.first.preheader:
br label %for.first
for.first:
%i = phi i64 [ %inc.i, %for.first ], [ 0, %for.first.preheader ]
%Ai = getelementptr inbounds i32, i32* %A, i64 %i
store i32 0, i32* %Ai, align 4
%inc.i = add nsw i64 %i, 1
%cmp.i = icmp slt i64 %inc.i, %N
br i1 %cmp.i, label %for.first, label %for.first.exit
for.first.exit:
br label %for.second.guard
for.second.guard:
br i1 %cmp.guard, label %for.second.preheader, label %for.end
for.second.preheader:
%add = add nsw i32 %x, 1
br label %for.second
for.second:
%j = phi i64 [ %inc.j, %for.second ], [ 0, %for.second.preheader ]
%Bj = getelementptr inbounds i32, i32* %B, i64 %j
store i32 0, i32* %Bj, align 4
%inc.j = add nsw i64 %j, 1
%cmp.j = icmp slt i64 %inc.j, %N
br i1 %cmp.j, label %for.second, label %for.second.exit
for.second.exit:
br label %for.end
for.end:
ret void
}
[LoopFusion] Move instructions from FC1.GuardBlock to FC0.GuardBlock and from FC0.ExitBlock to FC1.ExitBlock when proven safe. Summary: Currently LoopFusion give up when the second loop nest guard block or the first loop nest exit block is not empty. For example: if (0 < N) { for (int i = 0; i < N; ++i) {} x+=1; } y+=1; if (0 < N) { for (int i = 0; i < N; ++i) {} } The above example should be safe to fuse. This PR moves instructions in FC1 guard block (e.g. y+=1;) to FC0 guard block, or instructions in FC0 exit block (e.g. x+=1;) to FC1 exit block, which then LoopFusion is able to fuse them. Reviewer: kbarton, jdoerfert, Meinersbur, dmgreen, fhahn, hfinkel, bmahjour, etiotto Reviewed By: jdoerfert Subscribers: hiraditya, llvm-commits Tag: LLVM Differential Revision: https://reviews.llvm.org/D73641
2020-01-30 11:57:50 +08:00
; Test that `%add` is moved in for.second.exit, and the two loops for.first
; and for.second are fused.
; CHECK: void @moveinsts_exitblock
; CHECK-LABEL: for.first.guard:
; CHECK: br i1 %cmp.guard, label %for.first.preheader, label %for.end
; CHECK-LABEL: for.first.preheader:
; CHECK-NEXT: br label %for.first
; CHECK-LABEL: for.first:
; CHECK: br i1 %cmp.j, label %for.first, label %for.second.exit
; CHECK-LABEL: for.second.exit:
; CHECK-NEXT: %add = add nsw i32 %x, 1
; CHECK-NEXT: br label %for.end
; CHECK-LABEL: for.end:
; CHECK-NEXT: ret void
define void @moveinsts_exitblock(i32* noalias %A, i32* noalias %B, i64 %N, i32 %x) {
for.first.guard:
%cmp.guard = icmp slt i64 0, %N
br i1 %cmp.guard, label %for.first.preheader, label %for.second.guard
for.first.preheader:
br label %for.first
for.first:
%i.04 = phi i64 [ %inc, %for.first ], [ 0, %for.first.preheader ]
%arrayidx = getelementptr inbounds i32, i32* %A, i64 %i.04
store i32 0, i32* %arrayidx, align 4
%inc = add nsw i64 %i.04, 1
%cmp = icmp slt i64 %inc, %N
br i1 %cmp, label %for.first, label %for.first.exit
for.first.exit:
%add = add nsw i32 %x, 1
br label %for.second.guard
for.second.guard:
br i1 %cmp.guard, label %for.second.preheader, label %for.end
for.second.preheader:
br label %for.second
for.second:
%j.02 = phi i64 [ %inc6, %for.second ], [ 0, %for.second.preheader ]
%arrayidx4 = getelementptr inbounds i32, i32* %B, i64 %j.02
store i32 0, i32* %arrayidx4, align 4
%inc6 = add nsw i64 %j.02, 1
%cmp.j = icmp slt i64 %inc6, %N
br i1 %cmp.j, label %for.second, label %for.second.exit
for.second.exit:
br label %for.end
for.end:
ret void
}
; Test that `%add` is moved in for.first.guard, and the two loops for.first
; and for.second are fused.
; CHECK: void @moveinsts_guardblock
; CHECK-LABEL: for.first.guard:
; CHECK-NEXT: %cmp.guard = icmp slt i64 0, %N
; CHECK-NEXT: %add = add nsw i32 %x, 1
; CHECK: br i1 %cmp.guard, label %for.first.preheader, label %for.end
; CHECK-LABEL: for.first.preheader:
; CHECK-NEXT: br label %for.first
; CHECK-LABEL: for.first:
; CHECK: br i1 %cmp.j, label %for.first, label %for.second.exit
; CHECK-LABEL: for.second.exit:
; CHECK-NEXT: br label %for.end
; CHECK-LABEL: for.end:
; CHECK-NEXT: ret void
define void @moveinsts_guardblock(i32* noalias %A, i32* noalias %B, i64 %N, i32 %x) {
for.first.guard:
%cmp.guard = icmp slt i64 0, %N
br i1 %cmp.guard, label %for.first.preheader, label %for.second.guard
for.first.preheader:
br label %for.first
for.first:
%i.04 = phi i64 [ %inc, %for.first ], [ 0, %for.first.preheader ]
%arrayidx = getelementptr inbounds i32, i32* %A, i64 %i.04
store i32 0, i32* %arrayidx, align 4
%inc = add nsw i64 %i.04, 1
%cmp = icmp slt i64 %inc, %N
br i1 %cmp, label %for.first, label %for.first.exit
for.first.exit:
br label %for.second.guard
for.second.guard:
%add = add nsw i32 %x, 1
br i1 %cmp.guard, label %for.second.preheader, label %for.end
for.second.preheader:
br label %for.second
for.second:
%j.02 = phi i64 [ %inc6, %for.second ], [ 0, %for.second.preheader ]
%arrayidx4 = getelementptr inbounds i32, i32* %B, i64 %j.02
store i32 0, i32* %arrayidx4, align 4
%inc6 = add nsw i64 %j.02, 1
%cmp.j = icmp slt i64 %inc6, %N
br i1 %cmp.j, label %for.second, label %for.second.exit
for.second.exit:
br label %for.end
for.end:
ret void
}
[LoopFusion] Update second loop guard non loop successor phis incoming blocks. Summary: The current LoopFusion forget to update the incoming block of the phis in second loop guard non loop successor from second loop guard block to first loop guard block. A test case is provided to better understand the problem. Reviewed By: jdoerfert Subscribers: hiraditya, llvm-commits Tag: LLVM Differential Revision: https://reviews.llvm.org/D81421
2020-06-10 05:12:51 +08:00
; Test that the incoming block of `%j.lcssa` is updated correctly
; from for.second.guard to for.first.guard, and the two loops for.first and
; for.second are fused.
; CHECK: i64 @updatephi_guardnonloopblock
; CHECK-LABEL: for.first.guard:
; CHECK-NEXT: %cmp.guard = icmp slt i64 0, %N
; CHECK: br i1 %cmp.guard, label %for.first.preheader, label %for.end
; CHECK-LABEL: for.first.preheader:
; CHECK-NEXT: br label %for.first
; CHECK-LABEL: for.first:
; CHECK: br i1 %cmp.j, label %for.first, label %for.second.exit
; CHECK-LABEL: for.second.exit:
; CHECK-NEXT: br label %for.end
; CHECK-LABEL: for.end:
; CHECK-NEXT: %j.lcssa = phi i64 [ 0, %for.first.guard ], [ %j.02, %for.second.exit ]
; CHECK-NEXT: ret i64 %j.lcssa
define i64 @updatephi_guardnonloopblock(i32* noalias %A, i32* noalias %B, i64 %N, i32 %x) {
for.first.guard:
%cmp.guard = icmp slt i64 0, %N
br i1 %cmp.guard, label %for.first.preheader, label %for.second.guard
for.first.preheader:
br label %for.first
for.first:
%i.04 = phi i64 [ %inc, %for.first ], [ 0, %for.first.preheader ]
%arrayidx = getelementptr inbounds i32, i32* %A, i64 %i.04
store i32 0, i32* %arrayidx, align 4
%inc = add nsw i64 %i.04, 1
%cmp = icmp slt i64 %inc, %N
br i1 %cmp, label %for.first, label %for.first.exit
for.first.exit:
br label %for.second.guard
for.second.guard:
br i1 %cmp.guard, label %for.second.preheader, label %for.end
for.second.preheader:
br label %for.second
for.second:
%j.02 = phi i64 [ %inc6, %for.second ], [ 0, %for.second.preheader ]
%arrayidx4 = getelementptr inbounds i32, i32* %B, i64 %j.02
store i32 0, i32* %arrayidx4, align 4
%inc6 = add nsw i64 %j.02, 1
%cmp.j = icmp slt i64 %inc6, %N
br i1 %cmp.j, label %for.second, label %for.second.exit
for.second.exit:
br label %for.end
for.end:
%j.lcssa = phi i64 [ 0, %for.second.guard ], [ %j.02, %for.second.exit ]
ret i64 %j.lcssa
}