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llvm-6502/test/Transforms/DeadStoreElimination/inst-limits.ll
Hal Finkel 9d85eff56a [DSE] Remove no-data-layout-only type-based overlap checking 
DSE's overlap checking contained special logic, used only when no DataLayout
was available, which inferred a complete overwrite when the pointee types were
equal. This logic seems fine for regular loads/stores, but does not work for
memcpy and friends. Instead of fixing this, I'm just removing it.
Philosophically, transformations should not contain enhanced behavior used only
when data layout is lacking (data layout should be strictly additive), and
maintaining these rarely-tested code paths seems not worthwhile at this stage.

Credit to Aliaksei Zasenka for the bug report and the diagnosis. The test case
(slightly reduced from that provided by Aliaksei) replaces the original
contents of test/Transforms/DeadStoreElimination/no-targetdata.ll -- a few
other tests have been updated to have a data layout.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220035 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-17 11:56:00 +00:00

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; RUN: opt -S -dse < %s | FileCheck %s
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
; If there are two stores to the same location, DSE should be able to remove
; the first store if the two stores are separated by no more than 98
; instructions. The existence of debug intrinsics between the stores should
; not affect this instruction limit.
@x = global i32 0, align 4
; Function Attrs: nounwind
define i32 @test_within_limit() {
entry:
; The first store; later there is a second store to the same location,
; so this store should be optimized away by DSE.
; CHECK-NOT: store i32 1, i32* @x, align 4
store i32 1, i32* @x, align 4
; Insert 98 dummy instructions between the two stores
%0 = bitcast i32 0 to i32
%1 = bitcast i32 0 to i32
%2 = bitcast i32 0 to i32
%3 = bitcast i32 0 to i32
%4 = bitcast i32 0 to i32
%5 = bitcast i32 0 to i32
%6 = bitcast i32 0 to i32
%7 = bitcast i32 0 to i32
%8 = bitcast i32 0 to i32
%9 = bitcast i32 0 to i32
%10 = bitcast i32 0 to i32
%11 = bitcast i32 0 to i32
%12 = bitcast i32 0 to i32
%13 = bitcast i32 0 to i32
%14 = bitcast i32 0 to i32
%15 = bitcast i32 0 to i32
%16 = bitcast i32 0 to i32
%17 = bitcast i32 0 to i32
%18 = bitcast i32 0 to i32
%19 = bitcast i32 0 to i32
%20 = bitcast i32 0 to i32
%21 = bitcast i32 0 to i32
%22 = bitcast i32 0 to i32
%23 = bitcast i32 0 to i32
%24 = bitcast i32 0 to i32
%25 = bitcast i32 0 to i32
%26 = bitcast i32 0 to i32
%27 = bitcast i32 0 to i32
%28 = bitcast i32 0 to i32
%29 = bitcast i32 0 to i32
%30 = bitcast i32 0 to i32
%31 = bitcast i32 0 to i32
%32 = bitcast i32 0 to i32
%33 = bitcast i32 0 to i32
%34 = bitcast i32 0 to i32
%35 = bitcast i32 0 to i32
%36 = bitcast i32 0 to i32
%37 = bitcast i32 0 to i32
%38 = bitcast i32 0 to i32
%39 = bitcast i32 0 to i32
%40 = bitcast i32 0 to i32
%41 = bitcast i32 0 to i32
%42 = bitcast i32 0 to i32
%43 = bitcast i32 0 to i32
%44 = bitcast i32 0 to i32
%45 = bitcast i32 0 to i32
%46 = bitcast i32 0 to i32
%47 = bitcast i32 0 to i32
%48 = bitcast i32 0 to i32
%49 = bitcast i32 0 to i32
%50 = bitcast i32 0 to i32
%51 = bitcast i32 0 to i32
%52 = bitcast i32 0 to i32
%53 = bitcast i32 0 to i32
%54 = bitcast i32 0 to i32
%55 = bitcast i32 0 to i32
%56 = bitcast i32 0 to i32
%57 = bitcast i32 0 to i32
%58 = bitcast i32 0 to i32
%59 = bitcast i32 0 to i32
%60 = bitcast i32 0 to i32
%61 = bitcast i32 0 to i32
%62 = bitcast i32 0 to i32
%63 = bitcast i32 0 to i32
%64 = bitcast i32 0 to i32
%65 = bitcast i32 0 to i32
%66 = bitcast i32 0 to i32
%67 = bitcast i32 0 to i32
%68 = bitcast i32 0 to i32
%69 = bitcast i32 0 to i32
%70 = bitcast i32 0 to i32
%71 = bitcast i32 0 to i32
%72 = bitcast i32 0 to i32
%73 = bitcast i32 0 to i32
%74 = bitcast i32 0 to i32
%75 = bitcast i32 0 to i32
%76 = bitcast i32 0 to i32
%77 = bitcast i32 0 to i32
%78 = bitcast i32 0 to i32
%79 = bitcast i32 0 to i32
%80 = bitcast i32 0 to i32
%81 = bitcast i32 0 to i32
%82 = bitcast i32 0 to i32
%83 = bitcast i32 0 to i32
%84 = bitcast i32 0 to i32
%85 = bitcast i32 0 to i32
%86 = bitcast i32 0 to i32
%87 = bitcast i32 0 to i32
%88 = bitcast i32 0 to i32
%89 = bitcast i32 0 to i32
%90 = bitcast i32 0 to i32
%91 = bitcast i32 0 to i32
%92 = bitcast i32 0 to i32
%93 = bitcast i32 0 to i32
%94 = bitcast i32 0 to i32
%95 = bitcast i32 0 to i32
%96 = bitcast i32 0 to i32
%97 = bitcast i32 0 to i32
; Insert a meaningless dbg.value intrinsic; it should have no
; effect on the working of DSE in any way.
call void @llvm.dbg.value(metadata !12, i64 0, metadata !10, metadata !{})
; CHECK: store i32 -1, i32* @x, align 4
store i32 -1, i32* @x, align 4
ret i32 0
}
; Function Attrs: nounwind
define i32 @test_outside_limit() {
entry:
; The first store; later there is a second store to the same location
; CHECK: store i32 1, i32* @x, align 4
store i32 1, i32* @x, align 4
; Insert 99 dummy instructions between the two stores; this is
; one too many instruction for the DSE to take place.
%0 = bitcast i32 0 to i32
%1 = bitcast i32 0 to i32
%2 = bitcast i32 0 to i32
%3 = bitcast i32 0 to i32
%4 = bitcast i32 0 to i32
%5 = bitcast i32 0 to i32
%6 = bitcast i32 0 to i32
%7 = bitcast i32 0 to i32
%8 = bitcast i32 0 to i32
%9 = bitcast i32 0 to i32
%10 = bitcast i32 0 to i32
%11 = bitcast i32 0 to i32
%12 = bitcast i32 0 to i32
%13 = bitcast i32 0 to i32
%14 = bitcast i32 0 to i32
%15 = bitcast i32 0 to i32
%16 = bitcast i32 0 to i32
%17 = bitcast i32 0 to i32
%18 = bitcast i32 0 to i32
%19 = bitcast i32 0 to i32
%20 = bitcast i32 0 to i32
%21 = bitcast i32 0 to i32
%22 = bitcast i32 0 to i32
%23 = bitcast i32 0 to i32
%24 = bitcast i32 0 to i32
%25 = bitcast i32 0 to i32
%26 = bitcast i32 0 to i32
%27 = bitcast i32 0 to i32
%28 = bitcast i32 0 to i32
%29 = bitcast i32 0 to i32
%30 = bitcast i32 0 to i32
%31 = bitcast i32 0 to i32
%32 = bitcast i32 0 to i32
%33 = bitcast i32 0 to i32
%34 = bitcast i32 0 to i32
%35 = bitcast i32 0 to i32
%36 = bitcast i32 0 to i32
%37 = bitcast i32 0 to i32
%38 = bitcast i32 0 to i32
%39 = bitcast i32 0 to i32
%40 = bitcast i32 0 to i32
%41 = bitcast i32 0 to i32
%42 = bitcast i32 0 to i32
%43 = bitcast i32 0 to i32
%44 = bitcast i32 0 to i32
%45 = bitcast i32 0 to i32
%46 = bitcast i32 0 to i32
%47 = bitcast i32 0 to i32
%48 = bitcast i32 0 to i32
%49 = bitcast i32 0 to i32
%50 = bitcast i32 0 to i32
%51 = bitcast i32 0 to i32
%52 = bitcast i32 0 to i32
%53 = bitcast i32 0 to i32
%54 = bitcast i32 0 to i32
%55 = bitcast i32 0 to i32
%56 = bitcast i32 0 to i32
%57 = bitcast i32 0 to i32
%58 = bitcast i32 0 to i32
%59 = bitcast i32 0 to i32
%60 = bitcast i32 0 to i32
%61 = bitcast i32 0 to i32
%62 = bitcast i32 0 to i32
%63 = bitcast i32 0 to i32
%64 = bitcast i32 0 to i32
%65 = bitcast i32 0 to i32
%66 = bitcast i32 0 to i32
%67 = bitcast i32 0 to i32
%68 = bitcast i32 0 to i32
%69 = bitcast i32 0 to i32
%70 = bitcast i32 0 to i32
%71 = bitcast i32 0 to i32
%72 = bitcast i32 0 to i32
%73 = bitcast i32 0 to i32
%74 = bitcast i32 0 to i32
%75 = bitcast i32 0 to i32
%76 = bitcast i32 0 to i32
%77 = bitcast i32 0 to i32
%78 = bitcast i32 0 to i32
%79 = bitcast i32 0 to i32
%80 = bitcast i32 0 to i32
%81 = bitcast i32 0 to i32
%82 = bitcast i32 0 to i32
%83 = bitcast i32 0 to i32
%84 = bitcast i32 0 to i32
%85 = bitcast i32 0 to i32
%86 = bitcast i32 0 to i32
%87 = bitcast i32 0 to i32
%88 = bitcast i32 0 to i32
%89 = bitcast i32 0 to i32
%90 = bitcast i32 0 to i32
%91 = bitcast i32 0 to i32
%92 = bitcast i32 0 to i32
%93 = bitcast i32 0 to i32
%94 = bitcast i32 0 to i32
%95 = bitcast i32 0 to i32
%96 = bitcast i32 0 to i32
%97 = bitcast i32 0 to i32
%98 = bitcast i32 0 to i32
; CHECK: store i32 -1, i32* @x, align 4
store i32 -1, i32* @x, align 4
ret i32 0
}
; Function Attrs: nounwind readnone
declare void @llvm.dbg.value(metadata, i64, metadata, metadata)
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!11, !13}
!0 = metadata !{metadata !"0x11\004\00clang version 3.4\001\00\000\00\000", metadata !1, metadata !2, metadata !2, metadata !3, metadata !9, metadata !2} ; [ DW_TAG_compile_unit ] [/home/tmp/test.c] [DW_LANG_C99]
!1 = metadata !{metadata !"test.c", metadata !"/home/tmp"}
!2 = metadata !{i32 0}
!3 = metadata !{metadata !4}
!4 = metadata !{metadata !"0x2e\00test_within_limit\00test_within_limit\00\003\000\001\000\006\00256\000\004", metadata !1, metadata !5, metadata !6, null, i32 ()* @test_within_limit, null, null, metadata !2} ; [ DW_TAG_subprogram ] [line 3] [def] [scope 4] [test]
!5 = metadata !{metadata !"0x29", metadata !1} ; [ DW_TAG_file_type ] [/home/tmp/test.c]
!6 = metadata !{metadata !"0x15\00\000\000\000\000\000\000", i32 0, null, null, metadata !7, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
!7 = metadata !{metadata !8}
!8 = metadata !{metadata !"0x24\00int\000\0032\0032\000\000\005", null, null} ; [ DW_TAG_base_type ] [int] [line 0, size 32, align 32, offset 0, enc DW_ATE_signed]
!9 = metadata !{metadata !10}
!10 = metadata !{metadata !"0x34\00x\00x\00\001\000\001", null, metadata !5, metadata !8, i32* @x, null} ; [ DW_TAG_variable ] [x] [line 1] [def]
!11 = metadata !{i32 2, metadata !"Dwarf Version", i32 4}
!12 = metadata !{i32* undef}
!13 = metadata !{i32 1, metadata !"Debug Info Version", i32 2}
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