From d1ffc739c1f88352c79a63ff17b828b3a529777e Mon Sep 17 00:00:00 2001 From: Pete Cooper Date: Thu, 3 Nov 2011 00:56:36 +0000 Subject: [PATCH] Treat objc selector reference globals as invariant so that MachineLICM can hoist them out of loops. Fixes git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143600 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/MachineInstr.cpp | 15 ++++++++++ .../X86/MachineLICM-HoistSelectorRefs.ll | 30 +++++++++++++++++++ 2 files changed, 45 insertions(+) create mode 100644 test/CodeGen/X86/MachineLICM-HoistSelectorRefs.ll diff --git a/lib/CodeGen/MachineInstr.cpp b/lib/CodeGen/MachineInstr.cpp index a240667f7d6..a2fd3c46bf0 100644 --- a/lib/CodeGen/MachineInstr.cpp +++ b/lib/CodeGen/MachineInstr.cpp @@ -1232,6 +1232,19 @@ bool MachineInstr::hasVolatileMemoryRef() const { return false; } +/// pointsToRuntimeConstantMemory - Return true if this value points to data +/// which does never changes once the program starts running +static bool pointsToRuntimeConstantMemory(const Value *V) { + if (const GlobalVariable *GV = dyn_cast(V)) { + StringRef Name = GV->getName(); + // These special values are known to be constant at runtime + // TODO: a new linkage type for these would be far better than this check + if (Name.startswith("\01L_OBJC_SELECTOR_REFERENCES_")) + return true; + } + return false; +} + /// isInvariantLoad - Return true if this instruction is loading from a /// location whose value is invariant across the function. For example, /// loading a value from the constant pool or from the argument area @@ -1259,6 +1272,8 @@ bool MachineInstr::isInvariantLoad(AliasAnalysis *AA) const { if (const PseudoSourceValue *PSV = dyn_cast(V)) if (PSV->isConstant(MFI)) continue; + if (pointsToRuntimeConstantMemory(V)) + continue; // If we have an AliasAnalysis, ask it whether the memory is constant. if (AA && AA->pointsToConstantMemory( AliasAnalysis::Location(V, (*I)->getSize(), diff --git a/test/CodeGen/X86/MachineLICM-HoistSelectorRefs.ll b/test/CodeGen/X86/MachineLICM-HoistSelectorRefs.ll new file mode 100644 index 00000000000..bb0e0f29be9 --- /dev/null +++ b/test/CodeGen/X86/MachineLICM-HoistSelectorRefs.ll @@ -0,0 +1,30 @@ +; RUN: llc < %s -march=x86-64 -mattr=+sse3,+sse41 -stats |& grep {1 machine-licm} +; rdar://6027699 + +target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128" +target triple = "x86_64-apple-macosx10.7.2" + +; STATS: 1 machine-licm + +@"\01L_OBJC_METH_VAR_NAME_" = internal global [4 x i8] c"foo\00", section "__TEXT,__objc_methname,cstring_literals", align 1 +@"\01L_OBJC_SELECTOR_REFERENCES_" = internal global i8* getelementptr inbounds ([4 x i8]* @"\01L_OBJC_METH_VAR_NAME_", i64 0, i64 0), section "__DATA, __objc_selrefs, literal_pointers, no_dead_strip" +@"\01L_OBJC_IMAGE_INFO" = internal constant [2 x i32] [i32 0, i32 16], section "__DATA, __objc_imageinfo, regular, no_dead_strip" +@llvm.used = appending global [3 x i8*] [i8* getelementptr inbounds ([4 x i8]* @"\01L_OBJC_METH_VAR_NAME_", i32 0, i32 0), i8* bitcast (i8** @"\01L_OBJC_SELECTOR_REFERENCES_" to i8*), i8* bitcast ([2 x i32]* @"\01L_OBJC_IMAGE_INFO" to i8*)], section "llvm.metadata" + +define void @test(i8* %x) uwtable ssp { +entry: + br label %for.body + +for.body: ; preds = %for.body, %entry + %i.01 = phi i32 [ 0, %entry ], [ %inc, %for.body ] + %0 = load i8** @"\01L_OBJC_SELECTOR_REFERENCES_", align 8 + %call = tail call i8* bitcast (i8* (i8*, i8*, ...)* @objc_msgSend to i8* (i8*, i8*)*)(i8* %x, i8* %0) + %inc = add i32 %i.01, 1 + %exitcond = icmp eq i32 %inc, 10000 + br i1 %exitcond, label %for.end, label %for.body + +for.end: ; preds = %for.body + ret void +} + +declare i8* @objc_msgSend(i8*, i8*, ...) nonlazybind -- 2.34.1