Treat objc selector reference globals as invariant so that MachineLICM can hoist them out of loops. Fixes <rdar://problem/6027699>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143600 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachineInstr.cpp b/lib/CodeGen/MachineInstr.cpp
index a240667..a2fd3c4 100644
--- a/lib/CodeGen/MachineInstr.cpp
+++ b/lib/CodeGen/MachineInstr.cpp
@@ -1232,6 +1232,19 @@
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 @@
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(),
diff --git a/test/CodeGen/X86/MachineLICM-HoistSelectorRefs.ll b/test/CodeGen/X86/MachineLICM-HoistSelectorRefs.ll
new file mode 100644
index 0000000..bb0e0f2
--- /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