dfd14adeb0
Summary:
Two utils methods have essentially the same functionality. This is an attempt to merge them into one.
1. lib/Transforms/Utils/Local.cpp : MergeBasicBlockIntoOnlyPred
2. lib/Transforms/Utils/BasicBlockUtils.cpp : MergeBlockIntoPredecessor
Prior to the patch:
1. MergeBasicBlockIntoOnlyPred
Updates either DomTree or DeferredDominance
Moves all instructions from Pred to BB, deletes Pred
Asserts BB has single predecessor
If address was taken, replace the block address with constant 1 (?)
2. MergeBlockIntoPredecessor
Updates DomTree, LoopInfo and MemoryDependenceResults
Moves all instruction from BB to Pred, deletes BB
Returns if doesn't have a single predecessor
Returns if BB's address was taken
After the patch:
Method 2. MergeBlockIntoPredecessor is attempting to become the new default:
Updates DomTree or DeferredDominance, and LoopInfo and MemoryDependenceResults
Moves all instruction from BB to Pred, deletes BB
Returns if doesn't have a single predecessor
Returns if BB's address was taken
Uses of MergeBasicBlockIntoOnlyPred that need to be replaced:
1. lib/Transforms/Scalar/LoopSimplifyCFG.cpp
Updated in this patch. No challenges.
2. lib/CodeGen/CodeGenPrepare.cpp
Updated in this patch.
i. eliminateFallThrough is straightforward, but I added using a temporary array to avoid the iterator invalidation.
ii. eliminateMostlyEmptyBlock(s) methods also now use a temporary array for blocks
Some interesting aspects:
- Since Pred is not deleted (BB is), the entry block does not need updating.
- The entry block was being updated with the deleted block in eliminateMostlyEmptyBlock. Added assert to make obvious that BB=SinglePred.
- isMergingEmptyBlockProfitable assumes BB is the one to be deleted.
- eliminateMostlyEmptyBlock(BB) does not delete BB on one path, it deletes its unique predecessor instead.
- adding some test owner as subscribers for the interesting tests modified:
test/CodeGen/X86/avx-cmp.ll
test/CodeGen/AMDGPU/nested-loop-conditions.ll
test/CodeGen/AMDGPU/si-annotate-cf.ll
test/CodeGen/X86/hoist-spill.ll
test/CodeGen/X86/2006-11-17-IllegalMove.ll
3. lib/Transforms/Scalar/JumpThreading.cpp
Not covered in this patch. It is the only use case using the DeferredDominance.
I would defer to Brian Rzycki to make this replacement.
Reviewers: chandlerc, spatel, davide, brzycki, bkramer, javed.absar
Subscribers: qcolombet, sanjoy, nemanjai, nhaehnle, jlebar, tpr, kbarton, RKSimon, wmi, arsenm, llvm-commits
Differential Revision: https://reviews.llvm.org/D48202
llvm-svn: 335183
58 lines
1.6 KiB
LLVM
58 lines
1.6 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt -S -loop-simplifycfg -verify-scev < %s | FileCheck %s
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; Verify that the scev information is still valid. Verification should not fail
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define void @t_run_test() {
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; CHECK-LABEL: @t_run_test(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: br label %[[LOOP_PH:.*]]
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; CHECK: [[LOOP_PH]]:
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; CHECK-NEXT: br label %[[LOOP_BODY:.*]]
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; CHECK: [[LOOP_BODY]]:
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; CHECK-NEXT: [[IV:%.*]] = phi i32 [ 0, %[[LOOP_PH]] ], [ [[INC:%.*]], %[[LOOP_BODY]] ]
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; CHECK-NEXT: [[INC]] = add i32 [[IV]], 1
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; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[INC]], 10
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; CHECK-NEXT: br i1 [[CMP]], label %[[LOOP_BODY]], label %[[EXIT:.*]]
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; CHECK: [[EXIT]]:
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; CHECK-NEXT: br label %[[LOOP_BODY2:.*]]
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; CHECK: [[LOOP_BODY2]]:
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; CHECK-NEXT: [[IV2:%.*]] = phi i32 [ 0, %[[EXIT]] ], [ [[INC2:%.*]], %[[LOOP_BODY2]] ]
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; CHECK-NEXT: [[INC2]] = add i32 [[IV2]], 1
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; CHECK-NEXT: [[CMP2:%.*]] = icmp ult i32 [[INC2]], 10
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; CHECK-NEXT: br i1 [[CMP2]], label %[[LOOP_BODY2]], label %[[EXIT2:.*]]
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; CHECK: [[EXIT2]]:
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; CHECK-NEXT: ret void
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;
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entry:
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br label %loop.ph
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loop.ph:
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br label %loop.header
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loop.header:
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%iv = phi i32 [0, %loop.ph], [%inc, %loop.body]
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br label %loop.body1
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loop.body1:
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br label %loop.body
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loop.body:
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%inc = add i32 %iv, 1
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%cmp = icmp ult i32 %inc, 10
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br i1 %cmp, label %loop.header, label %exit
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exit:
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br label %loop.body2
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loop.body2:
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%iv2 = phi i32 [0, %exit], [%inc2, %loop.body2]
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%inc2 = add i32 %iv2, 1
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%cmp2 = icmp ult i32 %inc2, 10
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br i1 %cmp2, label %loop.body2, label %exit2
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exit2:
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ret void
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}
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