[GlobalMerge] Look at uses to create smaller global sets.
Instead of merging everything together, look at the users of
GlobalVariables, and try to group them by function, to create
sets of globals used "together".
Using that information, a less-aggressive alternative is to keep merging
everything together *except* globals that are only ever used alone, that
is, those for which it's clearly non-profitable to merge with others.
In my testing, grouping by Function is too aggressive, but grouping by
BasicBlock is too conservative. Anything in-between isn't trivially
available, so stick with Function grouping for now.
cl::opts are added for testing; both enabled by default.
A few of the testcases aren't testing the merging proper, but just
various edge cases when merging does occur. Update them to use the
previous grouping behavior. Also, one of the tests is unrelated to
GlobalMerge; change it accordingly.
While there, switch to r234666' flags rather than the brutal -O3.
Differential Revision: http://reviews.llvm.org/D8070
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235249 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-18 01:21:58 +00:00
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; RUN: llc < %s -mtriple=thumb-apple-darwin -arm-global-merge -global-merge-group-by-use=false -global-merge-on-const=true | FileCheck %s
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2010-11-17 21:25:27 +00:00
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; Test the ARMGlobalMerge pass. Use -march=thumb because it has a small
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; value for the maximum offset (127).
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; A local array that exceeds the maximum offset should not be merged.
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; CHECK: g0:
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@g0 = internal global [32 x i32] [ i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 1, i32 2 ]
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2013-03-18 22:30:07 +00:00
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; Global variables marked with "used" attribute must be kept
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; CHECK: g8
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@g8 = internal global i32 0
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@llvm.used = appending global [1 x i8*] [i8* bitcast (i32* @g8 to i8*)], section "llvm.metadata"
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; Global used in landing pad instruction must be kept
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; CHECK: ZTIi
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@_ZTIi = internal global i8* null
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2015-06-17 20:52:32 +00:00
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define i32 @_Z9exceptioni(i32 %arg) personality i8* bitcast (i32 (...)* @__gxx_personality_sj0 to i8*) {
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2013-03-18 22:30:07 +00:00
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bb:
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%tmp = invoke i32 @_Z14throwSomethingi(i32 %arg)
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to label %bb9 unwind label %bb1
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bb1: ; preds = %bb
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2015-06-17 20:52:32 +00:00
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%tmp2 = landingpad { i8*, i32 }
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2013-03-18 22:30:07 +00:00
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catch i8* bitcast (i8** @_ZTIi to i8*)
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%tmp3 = extractvalue { i8*, i32 } %tmp2, 1
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%tmp4 = tail call i32 @llvm.eh.typeid.for(i8* bitcast (i8** @_ZTIi to i8*))
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%tmp5 = icmp eq i32 %tmp3, %tmp4
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br i1 %tmp5, label %bb6, label %bb10
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bb6: ; preds = %bb1
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%tmp7 = extractvalue { i8*, i32 } %tmp2, 0
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%tmp8 = tail call i8* @__cxa_begin_catch(i8* %tmp7)
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tail call void @__cxa_end_catch()
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br label %bb9
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bb9: ; preds = %bb6, %bb
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%res.0 = phi i32 [ 0, %bb6 ], [ %tmp, %bb ]
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ret i32 %res.0
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bb10: ; preds = %bb1
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resume { i8*, i32 } %tmp2
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}
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declare i32 @_Z14throwSomethingi(i32)
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declare i32 @__gxx_personality_sj0(...)
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declare i32 @llvm.eh.typeid.for(i8*)
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declare i8* @__cxa_begin_catch(i8*)
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declare void @__cxa_end_catch()
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2010-11-17 21:25:33 +00:00
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; CHECK: _MergedGlobals:
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2010-11-17 21:25:27 +00:00
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@g1 = internal global i32 1
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@g2 = internal global i32 2
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2010-11-17 21:25:36 +00:00
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; Make sure that the complete variable fits within the range of the maximum
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; offset. Having the starting offset in range is not sufficient.
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; When this works properly, @g3 is placed in a separate chunk of merged globals.
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2015-05-12 16:47:30 +00:00
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; CHECK: _MergedGlobals.1:
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2011-11-30 21:54:15 +00:00
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@g3 = internal global [30 x i32] [ i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10 ], align 4
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2010-11-17 21:25:39 +00:00
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; Global variables that can be placed in BSS should be kept together in a
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; separate pool of merged globals.
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2015-05-12 16:47:30 +00:00
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; CHECK: _MergedGlobals.2
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2010-11-17 21:25:39 +00:00
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@g4 = internal global i32 0
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@g5 = internal global i32 0
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2013-03-18 22:30:07 +00:00
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; Global variables that are constant can be merged together
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2015-05-12 16:47:30 +00:00
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; CHECK: _MergedGlobals.3
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2013-03-18 22:30:07 +00:00
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@g6 = internal constant [12 x i32] zeroinitializer, align 4
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@g7 = internal constant [12 x i32] zeroinitializer, align 4
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