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
47 lines
1.7 KiB
LLVM
47 lines
1.7 KiB
LLVM
; RUN: opt -S -codegenprepare < %s | FileCheck %s
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;
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; This test case has been generated by hand but is inspired by the
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; observation that compares that are sunk into the basic blocks where
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; their results are used did not retain their debug locs. This caused
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; sample profiling to attribute code to the wrong source lines.
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;
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; We check that the compare instruction retains its debug loc after
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; it is sunk into other.bb by the codegen prepare pass.
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;
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; CHECK: entry:
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; CHECK-NEXT: icmp{{.*}}%x, 0, !dbg ![[MDHANDLE:[0-9]*]]
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; CHECK: ![[MDHANDLE]] = !DILocation(line: 2
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;
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target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
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define i32 @_Z3fooii(i32 %x, i32 %y) !dbg !5 {
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entry:
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%cmp17 = icmp sgt i32 %x, 0, !dbg !6
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br label %other.bb, !dbg !6
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other.bb:
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br i1 %cmp17, label %exit1.bb, label %exit2.bb, !dbg !7
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exit1.bb:
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%0 = add i32 %y, 42, !dbg !8
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ret i32 %0, !dbg !8
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exit2.bb:
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ret i32 44, !dbg !9
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}
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!llvm.dbg.cu = !{!0}
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!llvm.module.flags = !{!3, !4}
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!0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, producer: "clang", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, globals: !2)
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!1 = !DIFile(filename: "test.cpp", directory: "/debuginfo/bug/cgp")
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!2 = !{}
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!3 = !{i32 2, !"Dwarf Version", i32 4}
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!4 = !{i32 2, !"Debug Info Version", i32 3}
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!5 = distinct !DISubprogram(name: "foo", linkageName: "foo", scope: !1, file: !1, line: 1, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !2)
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!6 = !DILocation(line: 2, column: 0, scope: !5)
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!7 = !DILocation(line: 3, column: 0, scope: !5)
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!8 = !DILocation(line: 4, column: 0, scope: !5)
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!9 = !DILocation(line: 5, column: 0, scope: !5)
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