// for more information.
unsigned MaxOffset;
+ /// Whether we should try to optimize for size only.
+ /// Currently, this applies a dead simple heuristic: only consider globals
+ /// used in minsize functions for merging.
+ /// FIXME: This could learn about optsize, and be used in the cost model.
+ bool OnlyOptimizeForSize;
+
bool doMerge(SmallVectorImpl<GlobalVariable*> &Globals,
Module &M, bool isConst, unsigned AddrSpace) const;
/// \brief Merge everything in \p Globals for which the corresponding bit
public:
static char ID; // Pass identification, replacement for typeid.
explicit GlobalMerge(const TargetMachine *TM = nullptr,
- unsigned MaximalOffset = 0)
+ unsigned MaximalOffset = 0,
+ bool OnlyOptimizeForSize = false)
: FunctionPass(ID), TM(TM), DL(TM->getDataLayout()),
- MaxOffset(MaximalOffset) {
+ MaxOffset(MaximalOffset), OnlyOptimizeForSize(OnlyOptimizeForSize) {
initializeGlobalMergePass(*PassRegistry::getPassRegistry());
}
continue;
Function *ParentFn = I->getParent()->getParent();
+
+ // If we're only optimizing for size, ignore non-minsize functions.
+ if (OnlyOptimizeForSize &&
+ !ParentFn->hasFnAttribute(Attribute::MinSize))
+ continue;
+
size_t UGSIdx = GlobalUsesByFunction[ParentFn];
// If this is the first global the basic block uses, map it to the set
return false;
}
-Pass *llvm::createGlobalMergePass(const TargetMachine *TM, unsigned Offset) {
- return new GlobalMerge(TM, Offset);
+Pass *llvm::createGlobalMergePass(const TargetMachine *TM, unsigned Offset,
+ bool OnlyOptimizeForSize) {
+ return new GlobalMerge(TM, Offset, OnlyOptimizeForSize);
}
// FIXME: On AArch64, this depends on the type.
// Basically, the addressable offsets are up to 4095 * Ty.getSizeInBytes().
// and the offset has to be a multiple of the related size in bytes.
- if ((TM->getOptLevel() == CodeGenOpt::Aggressive &&
+ if ((TM->getOptLevel() != CodeGenOpt::None &&
EnableGlobalMerge == cl::BOU_UNSET) ||
- EnableGlobalMerge == cl::BOU_TRUE)
- addPass(createGlobalMergePass(TM, 4095));
+ EnableGlobalMerge == cl::BOU_TRUE) {
+ bool OnlyOptimizeForSize = (TM->getOptLevel() < CodeGenOpt::Aggressive) &&
+ (EnableGlobalMerge == cl::BOU_UNSET);
+ addPass(createGlobalMergePass(TM, 4095, OnlyOptimizeForSize));
+ }
+
if (TM->getOptLevel() != CodeGenOpt::None)
addPass(createAArch64AddressTypePromotionPass());
}
bool ARMPassConfig::addPreISel() {
- if ((TM->getOptLevel() == CodeGenOpt::Aggressive &&
+ if ((TM->getOptLevel() != CodeGenOpt::None &&
EnableGlobalMerge == cl::BOU_UNSET) ||
- EnableGlobalMerge == cl::BOU_TRUE)
+ EnableGlobalMerge == cl::BOU_TRUE) {
// FIXME: This is using the thumb1 only constant value for
// maximal global offset for merging globals. We may want
// to look into using the old value for non-thumb1 code of
// 4095 based on the TargetMachine, but this starts to become
// tricky when doing code gen per function.
- addPass(createGlobalMergePass(TM, 127));
+ bool OnlyOptimizeForSize = (TM->getOptLevel() < CodeGenOpt::Aggressive) &&
+ (EnableGlobalMerge == cl::BOU_UNSET);
+ addPass(createGlobalMergePass(TM, 127, OnlyOptimizeForSize));
+ }
return false;
}
--- /dev/null
+; RUN: llc -mtriple=aarch64-apple-ios -asm-verbose=false -aarch64-collect-loh=false \
+; RUN: -O1 -global-merge-group-by-use -global-merge-ignore-single-use \
+; RUN: %s -o - | FileCheck %s
+
+; Check that, at -O1, we only merge globals used in minsize functions.
+; We assume that globals of the same size aren't reordered inside a set.
+; We use -global-merge-ignore-single-use, and thus only expect one merged set.
+
+@m1 = internal global i32 0, align 4
+@n1 = internal global i32 0, align 4
+
+; CHECK-LABEL: f1:
+define void @f1(i32 %a1, i32 %a2) minsize nounwind {
+; CHECK-NEXT: adrp x8, [[SET:__MergedGlobals]]@PAGE
+; CHECK-NEXT: add x8, x8, [[SET]]@PAGEOFF
+; CHECK-NEXT: stp w0, w1, [x8]
+; CHECK-NEXT: ret
+ store i32 %a1, i32* @m1, align 4
+ store i32 %a2, i32* @n1, align 4
+ ret void
+}
+
+@m2 = internal global i32 0, align 4
+@n2 = internal global i32 0, align 4
+
+; CHECK-LABEL: f2:
+define void @f2(i32 %a1, i32 %a2) nounwind {
+; CHECK-NEXT: adrp x8, _m2@PAGE
+; CHECK-NEXT: adrp x9, _n2@PAGE
+; CHECK-NEXT: str w0, [x8, _m2@PAGEOFF]
+; CHECK-NEXT: str w1, [x9, _n2@PAGEOFF]
+; CHECK-NEXT: ret
+ store i32 %a1, i32* @m2, align 4
+ store i32 %a2, i32* @n2, align 4
+ ret void
+}
+
+; If we have use sets partially overlapping between a minsize and a non-minsize
+; function, explicitly check that we only consider the globals used in the
+; minsize function for merging.
+
+@m3 = internal global i32 0, align 4
+@n3 = internal global i32 0, align 4
+
+; CHECK-LABEL: f3:
+define void @f3(i32 %a1, i32 %a2) minsize nounwind {
+; CHECK-NEXT: adrp x8, [[SET]]@PAGE
+; CHECK-NEXT: add x8, x8, [[SET]]@PAGEOFF
+; CHECK-NEXT: stp w0, w1, [x8, #8]
+; CHECK-NEXT: ret
+ store i32 %a1, i32* @m3, align 4
+ store i32 %a2, i32* @n3, align 4
+ ret void
+}
+
+@n4 = internal global i32 0, align 4
+
+; CHECK-LABEL: f4:
+define void @f4(i32 %a1, i32 %a2) nounwind {
+; CHECK-NEXT: adrp x8, [[SET]]@PAGE
+; CHECK-NEXT: add x8, x8, [[SET]]@PAGEOFF
+; CHECK-NEXT: adrp x9, _n4@PAGE
+; CHECK-NEXT: str w0, [x8, #8]
+; CHECK-NEXT: str w1, [x9, _n4@PAGEOFF]
+; CHECK-NEXT: ret
+ store i32 %a1, i32* @m3, align 4
+ store i32 %a2, i32* @n4, align 4
+ ret void
+}
+
+; CHECK-DAG: .zerofill __DATA,__bss,[[SET]],16,3
+; CHECK-DAG: .zerofill __DATA,__bss,_m2,4,2
+; CHECK-DAG: .zerofill __DATA,__bss,_n2,4,2
+; CHECK-DAG: .zerofill __DATA,__bss,_n4,4,2