[LoopUtils] Extend findStringMetadataForLoop to return the value for metadata
E.g. for:
!1 = {"llvm.distribute", i32 1}
it now returns the MDOperand for 1.
I will use this in LoopDistribution to check the value of the metadata.
Note that the change is backward-compatible with its current use in
LoopVersioningLICM. An Optional implicitly converts to a bool depending
whether it contains a value or not.
llvm-svn: 267190
diff --git a/llvm/lib/Transforms/Utils/LoopUtils.cpp b/llvm/lib/Transforms/Utils/LoopUtils.cpp
index 2f74b11..2d1f10f 100644
--- a/llvm/lib/Transforms/Utils/LoopUtils.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUtils.cpp
@@ -823,13 +823,17 @@
INITIALIZE_PASS_DEPENDENCY(ScalarEvolutionWrapperPass)
}
-/// \brief Find string metadata for loop, if it exists return true, else return
-/// false.
-bool llvm::findStringMetadataForLoop(Loop *TheLoop, StringRef Name) {
+/// \brief Find string metadata for loop
+///
+/// If it has a value (e.g. {"llvm.distribute", 1} return the value as an
+/// operand or null otherwise. If the string metadata is not found return
+/// Optional's not-a-value.
+Optional<const MDOperand *> llvm::findStringMetadataForLoop(Loop *TheLoop,
+ StringRef Name) {
MDNode *LoopID = TheLoop->getLoopID();
- // Return false if LoopID is false.
+ // Return none if LoopID is false.
if (!LoopID)
- return false;
+ return None;
// First operand should refer to the loop id itself.
assert(LoopID->getNumOperands() > 0 && "requires at least one operand");
@@ -845,7 +849,14 @@
continue;
// Return true if MDString holds expected MetaData.
if (Name.equals(S->getString()))
- return true;
+ switch (MD->getNumOperands()) {
+ case 1:
+ return nullptr;
+ case 2:
+ return &MD->getOperand(1);
+ default:
+ llvm_unreachable("loop metadata has 0 or 1 operand");
+ }
}
- return false;
+ return None;
}