Add llvm.licm.disable metadata
For some targets the LICM pass can result in sub-optimal code in some
cases where it would be better not to run the pass, but it isn't
always possible to suppress the transformations heuristically.
Where the front-end has insight into such cases it is beneficial
to attach loop metadata to disable the pass - this change adds the
llvm.licm.disable metadata to enable that.
Differential Revision: https://reviews.llvm.org/D64557
llvm-svn: 368296
diff --git a/llvm/lib/Transforms/Utils/LoopUtils.cpp b/llvm/lib/Transforms/Utils/LoopUtils.cpp
index ce296b9..4c6c2ed 100644
--- a/llvm/lib/Transforms/Utils/LoopUtils.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUtils.cpp
@@ -45,6 +45,7 @@
#define DEBUG_TYPE "loop-utils"
static const char *LLVMLoopDisableNonforced = "llvm.loop.disable_nonforced";
+static const char *LLVMLoopDisableLICM = "llvm.licm.disable";
bool llvm::formDedicatedExitBlocks(Loop *L, DominatorTree *DT, LoopInfo *LI,
MemorySSAUpdater *MSSAU,
@@ -379,6 +380,10 @@
return getBooleanLoopAttribute(L, LLVMLoopDisableNonforced);
}
+bool llvm::hasDisableLICMTransformsHint(const Loop *L) {
+ return getBooleanLoopAttribute(L, LLVMLoopDisableLICM);
+}
+
TransformationMode llvm::hasUnrollTransformation(Loop *L) {
if (getBooleanLoopAttribute(L, "llvm.loop.unroll.disable"))
return TM_SuppressedByUser;