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[GlobalMerge] Aggressively merge constants to reduce TOC entries #111756

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Merged
merged 1 commit into from
Oct 24, 2024
Merged

[GlobalMerge] Aggressively merge constants to reduce TOC entries #111756

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7 changes: 6 additions & 1 deletion llvm/lib/CodeGen/GlobalMerge.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -119,6 +119,11 @@ static cl::opt<bool> GlobalMergeGroupByUse(
"global-merge-group-by-use", cl::Hidden,
cl::desc("Improve global merge pass to look at uses"), cl::init(true));

static cl::opt<bool> GlobalMergeAllConst(
"global-merge-all-const", cl::Hidden,
cl::desc("Merge all const globals without looking at uses"),
cl::init(false));

static cl::opt<bool> GlobalMergeIgnoreSingleUse(
"global-merge-ignore-single-use", cl::Hidden,
cl::desc("Improve global merge pass to ignore globals only used alone"),
Expand Down Expand Up @@ -263,7 +268,7 @@ bool GlobalMergeImpl::doMerge(SmallVectorImpl<GlobalVariable *> &Globals,
});

// If we want to just blindly group all globals together, do so.
if (!GlobalMergeGroupByUse) {
if (!GlobalMergeGroupByUse || (GlobalMergeAllConst && isConst)) {
BitVector AllGlobals(Globals.size());
AllGlobals.set();
return doMerge(Globals, AllGlobals, M, isConst, AddrSpace);
Expand Down
93 changes: 93 additions & 0 deletions llvm/test/CodeGen/PowerPC/aix-aggressive-merge-const.ll
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Original file line number Diff line number Diff line change
@@ -0,0 +1,93 @@
; RUN: llc --verify-machineinstrs -mtriple powerpc-ibm-aix-xcoff \
; RUN: -global-merge-all-const=true < %s | FileCheck %s

; RUN: llc --verify-machineinstrs -mtriple powerpc-ibm-aix-xcoff \
; RUN: -global-merge-all-const=false < %s | FileCheck --check-prefix=NOMERGE %s

%struct.pc_t = type { i8 }
%struct.S = type { i32, i32, i32, i32, [9 x i32] }

@constinit = private unnamed_addr constant <{ i32, i32, i32, i32, [9 x i32] }> <{ i32 0, i32 0, i32 0, i32 2, [9 x i32] zeroinitializer }>, align 4
@.str = private unnamed_addr constant [6 x i8] c"hello\00", align 1
@.str.1 = private unnamed_addr constant [6 x i8] c"world\00", align 1
@.str.2 = private unnamed_addr constant [6 x i8] c"abcde\00", align 1
@.str.3 = private unnamed_addr constant [6 x i8] c"fghij\00", align 1
@pc = internal constant %struct.pc_t zeroinitializer, align 1
@s = internal constant %struct.S { i32 1, i32 2, i32 3, i32 4, [9 x i32] [i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13] }, align 4

; Function Attrs: mustprogress
define noundef i32 @f5() {
entry:
%call = tail call noundef i32 @f4(ptr noundef nonnull @pc)
ret i32 %call
}

declare noundef i32 @f4(ptr noundef)
declare noundef i32 @printf(ptr nocapture noundef readonly, ...)

define noundef i32 @f1() {
entry:
%call = tail call i32 (ptr, ...) @printf(ptr noundef nonnull dereferenceable(1) @.str)
ret i32 %call
}


; Function Attrs: mustprogress nofree nounwind
define noundef i32 @f2() {
entry:
%call = tail call i32 (ptr, ...) @printf(ptr noundef nonnull dereferenceable(1) @.str.1)
ret i32 %call
}

define noundef i32 @f3() {
entry:
%call = tail call i32 (ptr, ...) @printf(ptr noundef nonnull dereferenceable(1) @.str.2)
ret i32 %call
}

define noundef i32 @f7() {
entry:
%call = tail call noundef i32 @f6(ptr noundef nonnull @s)
ret i32 %call
}

declare noundef i32 @f6(ptr noundef)

; CHECK: .csect L.._MergedGlobals[RO],2
; CHECK-NEXT: .lglobl pc # @_MergedGlobals
; CHECK-NEXT: .lglobl s
; CHECK-NEXT: .align 2
; CHECK-NEXT:pc:
; CHECK-NEXT: .space 1
; CHECK-NEXT:L...str:
; CHECK-NEXT: .string "hello"
; CHECK-NEXT:L...str.1:
; CHECK-NEXT: .string "world"
; CHECK-NEXT:L...str.2:
; CHECK-NEXT: .string "abcde"
; CHECK-NEXT:L...str.3:
; CHECK-NEXT: .string "fghij"
; CHECK-NEXT: .space 3
; CHECK-NEXT:L..constinit:
; CHECK-NEXT: .vbyte 4, 0 # 0x0
; CHECK-NEXT: .vbyte 4, 0 # 0x0
; CHECK-NEXT: .vbyte 4, 0 # 0x0
; CHECK-NEXT: .vbyte 4, 2 # 0x2
; CHECK-NEXT: .space 36
; CHECK-NEXT:s:
; CHECK-NEXT: .vbyte 4, 1 # 0x1
; CHECK-NEXT: .vbyte 4, 2 # 0x2
; CHECK-NEXT: .vbyte 4, 3 # 0x3
; CHECK-NEXT: .vbyte 4, 4 # 0x4
; CHECK-NEXT: .vbyte 4, 5 # 0x5
; CHECK-NEXT: .vbyte 4, 6 # 0x6
; CHECK-NEXT: .vbyte 4, 7 # 0x7
; CHECK-NEXT: .vbyte 4, 8 # 0x8
; CHECK-NEXT: .vbyte 4, 9 # 0x9
; CHECK-NEXT: .vbyte 4, 10 # 0xa
; CHECK-NEXT: .vbyte 4, 11 # 0xb
; CHECK-NEXT: .vbyte 4, 12 # 0xc
; CHECK-NEXT: .vbyte 4, 13 # 0xd


; NOMERGE-NOT: L.._MergedGGlobals[RO]
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