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Treat objc selector reference globals as invariant so that MachineLICM can hoist them out of loops. Fixes <rdar://problem/6027699>

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143600 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Pete Cooper 2011-11-03 00:56:36 +00:00
parent cde5464970
commit d1ffc739c1
2 changed files with 45 additions and 0 deletions
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15
lib/CodeGen/MachineInstr.cpp
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@ -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<GlobalVariable>(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<PseudoSourceValue>(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(),

30
test/CodeGen/X86/MachineLICM-HoistSelectorRefs.ll Normal file
View File

@ -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