[LCSSA] Perform LCSSA verification only for the current loop nest.
Now LPPassManager will run LCSSA verification only for the top-level loop
which was processed on the current iteration.
Differential Revision: https://reviews.llvm.org/D25873
llvm-svn: 285394
diff --git a/llvm/lib/Transforms/Utils/LCSSA.cpp b/llvm/lib/Transforms/Utils/LCSSA.cpp
index 5d818cc..68c6b74 100644
--- a/llvm/lib/Transforms/Utils/LCSSA.cpp
+++ b/llvm/lib/Transforms/Utils/LCSSA.cpp
@@ -51,6 +51,15 @@
STATISTIC(NumLCSSA, "Number of live out of a loop variables");
+#ifdef EXPENSIVE_CHECKS
+static bool VerifyLoopLCSSA = true;
+#else
+static bool VerifyLoopLCSSA = false;
+#endif
+static cl::opt<bool,true>
+VerifyLoopLCSSAFlag("verify-loop-lcssa", cl::location(VerifyLoopLCSSA),
+ cl::desc("Verify loop lcssa form (time consuming)"));
+
/// Return true if the specified block is in the list.
static bool isExitBlock(BasicBlock *BB,
const SmallVectorImpl<BasicBlock *> &ExitBlocks) {
@@ -322,10 +331,17 @@
bool runOnFunction(Function &F) override;
void verifyAnalysis() const override {
- assert(
- all_of(*LI,
- [&](Loop *L) { return L->isRecursivelyLCSSAForm(*DT, *LI); }) &&
- "LCSSA form is broken!");
+ // This check is very expensive. On the loop intensive compiles it may cause
+ // up to 10x slowdown. Currently it's disabled by default. LPPassManager
+ // always does limited form of the LCSSA verification. Similar reasoning
+ // was used for the LoopInfo verifier.
+ if (VerifyLoopLCSSA) {
+ assert(all_of(*LI,
+ [&](Loop *L) {
+ return L->isRecursivelyLCSSAForm(*DT, *LI);
+ }) &&
+ "LCSSA form is broken!");
+ }
};
/// This transformation requires natural loop information & requires that
@@ -342,6 +358,10 @@
AU.addPreserved<GlobalsAAWrapperPass>();
AU.addPreserved<ScalarEvolutionWrapperPass>();
AU.addPreserved<SCEVAAWrapperPass>();
+
+ // This is needed to perform LCSSA verification inside LPPassManager
+ AU.addRequired<LCSSAVerificationPass>();
+ AU.addPreserved<LCSSAVerificationPass>();
}
};
}
@@ -351,6 +371,7 @@
false, false)
INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(LCSSAVerificationPass)
INITIALIZE_PASS_END(LCSSAWrapperPass, "lcssa", "Loop-Closed SSA Form Pass",
false, false)
diff --git a/llvm/lib/Transforms/Utils/LoopUtils.cpp b/llvm/lib/Transforms/Utils/LoopUtils.cpp
index 8878689..824bc14 100644
--- a/llvm/lib/Transforms/Utils/LoopUtils.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUtils.cpp
@@ -17,6 +17,7 @@
#include "llvm/Analysis/GlobalsModRef.h"
#include "llvm/Analysis/GlobalsModRef.h"
#include "llvm/Analysis/LoopInfo.h"
+#include "llvm/Analysis/LoopPass.h"
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Analysis/ScalarEvolutionAliasAnalysis.h"
#include "llvm/Analysis/ScalarEvolutionExpander.h"
@@ -946,6 +947,10 @@
AU.addPreservedID(LoopSimplifyID);
AU.addRequiredID(LCSSAID);
AU.addPreservedID(LCSSAID);
+ // This is used in the LPPassManager to perform LCSSA verification on passes
+ // which preserve lcssa form
+ AU.addRequired<LCSSAVerificationPass>();
+ AU.addPreserved<LCSSAVerificationPass>();
// Loop passes are designed to run inside of a loop pass manager which means
// that any function analyses they require must be required by the first loop