LICM pass now understands invariant load metadata. Nothing generates this yet so it will currently never get used in real tests

llvm-svn: 144107

2 files changed, 41 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/Scalar/LICM.cpp b/llvm/lib/Transforms/Scalar/LICM.cpp
index b79bb1300fe..8098b3608e9 100644
--- a/llvm/lib/Transforms/Scalar/LICM.cpp
+++ b/llvm/lib/Transforms/Scalar/LICM.cpp
@@ -369,6 +369,8 @@ bool LICM::canSinkOrHoistInst(Instruction &I) {
     // in the same alias set as something that ends up being modified.
     if (AA->pointsToConstantMemory(LI->getOperand(0)))
       return true;
+    if (LI->getMetadata(LI->getContext().getMDKindID("invariant.load")))
+      return true;
 
     // Don't hoist loads which have may-aliased stores in loop.
     uint64_t Size = 0;
diff --git a/llvm/test/Transforms/LICM/hoist-invariant-load.ll b/llvm/test/Transforms/LICM/hoist-invariant-load.ll
new file mode 100644
index 00000000000..4e100d3aee3
--- /dev/null
+++ b/llvm/test/Transforms/LICM/hoist-invariant-load.ll
@@ -0,0 +1,39 @@
+; RUN: opt < %s -licm -stats -S |& grep "1 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_", i32 0, i32 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:
+  %x.addr = alloca i8*, align 8
+  %i = alloca i32, align 4
+  store i8* %x, i8** %x.addr, align 8
+  store i32 0, i32* %i, align 4
+  br label %for.cond
+
+for.cond:                                         ; preds = %for.inc, %entry
+  %0 = load i32* %i, align 4
+  %cmp = icmp ult i32 %0, 10000
+  br i1 %cmp, label %for.body, label %for.end
+
+for.body:                                         ; preds = %for.cond
+  %1 = load i8** %x.addr, align 8
+  %2 = load i8** @"\01L_OBJC_SELECTOR_REFERENCES_", !invariant.load !0
+  %call = call i8* bitcast (i8* (i8*, i8*, ...)* @objc_msgSend to i8* (i8*, i8*)*)(i8* %1, i8* %2)
+  br label %for.inc
+
+for.inc:                                          ; preds = %for.body
+  %3 = load i32* %i, align 4
+  %inc = add i32 %3, 1
+  store i32 %inc, i32* %i, align 4
+  br label %for.cond
+
+for.end:                                          ; preds = %for.cond
+  ret void
+}
+
+declare i8* @objc_msgSend(i8*, i8*, ...) nonlazybind
+
+!0 = metadata !{}