freebsd-dev/contrib/llvm/patches/patch-04-add-llvm-gvn-option.diff

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Add an llvm option to enable/disable running the global value numbering
optimization pass. Disabling this pass helps to minimize the size of
boot2.
Introduced here: http://svnweb.freebsd.org/changeset/base/274968
Index: lib/Transforms/IPO/PassManagerBuilder.cpp
===================================================================
--- lib/Transforms/IPO/PassManagerBuilder.cpp
+++ lib/Transforms/IPO/PassManagerBuilder.cpp
@@ -78,6 +78,10 @@ static cl::opt<bool>
EnableMLSM("mlsm", cl::init(true), cl::Hidden,
cl::desc("Enable motion of merged load and store"));
+static cl::opt<bool> EnableGVN("enable-gvn",
+ cl::init(true), cl::Hidden,
+ cl::desc("Run the global value numbering pass"));
+
PassManagerBuilder::PassManagerBuilder() {
OptLevel = 2;
SizeLevel = 0;
@@ -244,7 +248,8 @@ void PassManagerBuilder::populateModulePassManager
if (OptLevel > 1) {
if (EnableMLSM)
MPM.add(createMergedLoadStoreMotionPass()); // Merge ld/st in diamonds
- MPM.add(createGVNPass(DisableGVNLoadPRE)); // Remove redundancies
+ if (EnableGVN)
+ MPM.add(createGVNPass(DisableGVNLoadPRE)); // Remove redundancies
}
MPM.add(createMemCpyOptPass()); // Remove memcpy / form memset
MPM.add(createSCCPPass()); // Constant prop with SCCP