[llvm] fbf6c8a - [LoopVersioning] Allow versionLoop to create plain branch inst when no runtime check is specified
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llvm-commits at lists.llvm.org
Thu Dec 16 00:41:35 PST 2021
Author: Yueh-Ting Chen
Date: 2021-12-16T00:41:29-08:00
New Revision: fbf6c8ac1589a4be68ee549257f1d528937ac582
URL: https://github.com/llvm/llvm-project/commit/fbf6c8ac1589a4be68ee549257f1d528937ac582
DIFF: https://github.com/llvm/llvm-project/commit/fbf6c8ac1589a4be68ee549257f1d528937ac582.diff
LOG: [LoopVersioning] Allow versionLoop to create plain branch inst when no runtime check is specified
After this function call, the LLVM IR would look like the following:
```
if (true)
/* NonVersionedLoop */
else
/* VersionedLoop */
```
Reviewed By: Whitney
Differential Revision: https://reviews.llvm.org/D104631
Added:
Modified:
llvm/include/llvm/Transforms/Utils/LoopVersioning.h
llvm/lib/Transforms/Utils/LoopVersioning.cpp
Removed:
################################################################################
diff --git a/llvm/include/llvm/Transforms/Utils/LoopVersioning.h b/llvm/include/llvm/Transforms/Utils/LoopVersioning.h
index 4a8831ed45b25..abf5acc377e4e 100644
--- a/llvm/include/llvm/Transforms/Utils/LoopVersioning.h
+++ b/llvm/include/llvm/Transforms/Utils/LoopVersioning.h
@@ -75,6 +75,12 @@ class LoopVersioning {
/// loop may alias (i.e. one of the memchecks failed).
Loop *getNonVersionedLoop() { return NonVersionedLoop; }
+ /// Returns the basic block that contains the runtime check BranchInst
+ BasicBlock *getRuntimeCheckBB() { return RuntimeCheckBB; }
+
+ /// Returns the runtime check BranchInst
+ BranchInst *getRuntimeCheckBI() { return RuntimeCheckBI; }
+
/// Annotate memory instructions in the versioned loop with no-alias
/// metadata based on the memchecks issued.
///
@@ -115,6 +121,12 @@ class LoopVersioning {
/// loop may alias (memchecks failed).
Loop *NonVersionedLoop;
+ /// The basic Block that stores the BranchInst to Versioned / NonVersioned
+ BasicBlock *RuntimeCheckBB;
+
+ /// The branch instruction to Versioned / NonVersioned
+ BranchInst *RuntimeCheckBI;
+
/// This maps the instructions from VersionedLoop to their counterpart
/// in NonVersionedLoop.
ValueToValueMapTy VMap;
diff --git a/llvm/lib/Transforms/Utils/LoopVersioning.cpp b/llvm/lib/Transforms/Utils/LoopVersioning.cpp
index 771b7d25b0f20..15a40cac8c110 100644
--- a/llvm/lib/Transforms/Utils/LoopVersioning.cpp
+++ b/llvm/lib/Transforms/Utils/LoopVersioning.cpp
@@ -30,6 +30,9 @@
using namespace llvm;
+#define LVER_OPTION "loop-versioning"
+#define DEBUG_TYPE LVER_OPTION
+
static cl::opt<bool>
AnnotateNoAlias("loop-version-annotate-no-alias", cl::init(true),
cl::Hidden,
@@ -84,8 +87,11 @@ void LoopVersioning::versionLoop(
} else
RuntimeCheck = MemRuntimeCheck ? MemRuntimeCheck : SCEVRuntimeCheck;
- assert(RuntimeCheck && "called even though we don't need "
- "any runtime checks");
+ if (!RuntimeCheck) {
+ LLVM_DEBUG(dbgs() << DEBUG_TYPE " No MemRuntimeCheck or SCEVRuntimeCheck found"
+ << ", set RuntimeCheck to False\n");
+ RuntimeCheck = ConstantInt::getFalse(RuntimeCheckBB->getContext());
+ }
// Rename the block to make the IR more readable.
RuntimeCheckBB->setName(VersionedLoop->getHeader()->getName() +
@@ -109,8 +115,8 @@ void LoopVersioning::versionLoop(
// Insert the conditional branch based on the result of the memchecks.
Instruction *OrigTerm = RuntimeCheckBB->getTerminator();
- BranchInst::Create(NonVersionedLoop->getLoopPreheader(),
- VersionedLoop->getLoopPreheader(), RuntimeCheck, OrigTerm);
+ RuntimeCheckBI = BranchInst::Create(NonVersionedLoop->getLoopPreheader(),
+ VersionedLoop->getLoopPreheader(), RuntimeCheck, OrigTerm);
OrigTerm->eraseFromParent();
// The loops merge in the original exit block. This is now dominated by the
@@ -125,6 +131,9 @@ void LoopVersioning::versionLoop(
assert(NonVersionedLoop->isLoopSimplifyForm() &&
VersionedLoop->isLoopSimplifyForm() &&
"The versioned loops should be in simplify form.");
+
+ // RuntimeCheckBB and RuntimeCheckBI is recorded
+ assert(RuntimeCheckBB && RuntimeCheckBI);
}
void LoopVersioning::addPHINodes(
@@ -324,9 +333,6 @@ class LoopVersioningLegacyPass : public FunctionPass {
};
}
-#define LVER_OPTION "loop-versioning"
-#define DEBUG_TYPE LVER_OPTION
-
char LoopVersioningLegacyPass::ID;
static const char LVer_name[] = "Loop Versioning";
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