Meinersbur created this revision.
Meinersbur added reviewers: hfinkel, jdoerfert.
getLoopID has different control flow for two cases: If there is a single loop
latch and for any other number of loop latches (0 and more than one). The
latter case should return the same result if there is a single latch. We can
save an iteration over the loop's basic blocks (which is what getLoopLatch
does) by handling both cases with the same code.
Repository:
rC Clang
https://reviews.llvm.org/D52118
Files:
lib/Analysis/LoopInfo.cpp
Index: lib/Analysis/LoopInfo.cpp
===================================================================
--- lib/Analysis/LoopInfo.cpp
+++ lib/Analysis/LoopInfo.cpp
@@ -213,26 +213,21 @@
MDNode *Loop::getLoopID() const {
MDNode *LoopID = nullptr;
- if (BasicBlock *Latch = getLoopLatch()) {
- LoopID = Latch->getTerminator()->getMetadata(LLVMContext::MD_loop);
- } else {
- assert(!getLoopLatch() &&
- "The loop should have no single latch at this point");
- // Go through the latch blocks and check the terminator for the metadata.
- SmallVector<BasicBlock *, 4> LatchesBlocks;
- getLoopLatches(LatchesBlocks);
- for (BasicBlock *BB : LatchesBlocks) {
- TerminatorInst *TI = BB->getTerminator();
- MDNode *MD = TI->getMetadata(LLVMContext::MD_loop);
-
- if (!MD)
- return nullptr;
-
- if (!LoopID)
- LoopID = MD;
- else if (MD != LoopID)
- return nullptr;
- }
+
+ // Go through the latch blocks and check the terminator for the metadata.
+ SmallVector<BasicBlock *, 4> LatchesBlocks;
+ getLoopLatches(LatchesBlocks);
+ for (BasicBlock *BB : LatchesBlocks) {
+ TerminatorInst *TI = BB->getTerminator();
+ MDNode *MD = TI->getMetadata(LLVMContext::MD_loop);
+
+ if (!MD)
+ return nullptr;
+
+ if (!LoopID)
+ LoopID = MD;
+ else if (MD != LoopID)
+ return nullptr;
}
if (!LoopID || LoopID->getNumOperands() == 0 ||
LoopID->getOperand(0) != LoopID)
Index: lib/Analysis/LoopInfo.cpp
===================================================================
--- lib/Analysis/LoopInfo.cpp
+++ lib/Analysis/LoopInfo.cpp
@@ -213,26 +213,21 @@
MDNode *Loop::getLoopID() const {
MDNode *LoopID = nullptr;
- if (BasicBlock *Latch = getLoopLatch()) {
- LoopID = Latch->getTerminator()->getMetadata(LLVMContext::MD_loop);
- } else {
- assert(!getLoopLatch() &&
- "The loop should have no single latch at this point");
- // Go through the latch blocks and check the terminator for the metadata.
- SmallVector<BasicBlock *, 4> LatchesBlocks;
- getLoopLatches(LatchesBlocks);
- for (BasicBlock *BB : LatchesBlocks) {
- TerminatorInst *TI = BB->getTerminator();
- MDNode *MD = TI->getMetadata(LLVMContext::MD_loop);
-
- if (!MD)
- return nullptr;
-
- if (!LoopID)
- LoopID = MD;
- else if (MD != LoopID)
- return nullptr;
- }
+
+ // Go through the latch blocks and check the terminator for the metadata.
+ SmallVector<BasicBlock *, 4> LatchesBlocks;
+ getLoopLatches(LatchesBlocks);
+ for (BasicBlock *BB : LatchesBlocks) {
+ TerminatorInst *TI = BB->getTerminator();
+ MDNode *MD = TI->getMetadata(LLVMContext::MD_loop);
+
+ if (!MD)
+ return nullptr;
+
+ if (!LoopID)
+ LoopID = MD;
+ else if (MD != LoopID)
+ return nullptr;
}
if (!LoopID || LoopID->getNumOperands() == 0 ||
LoopID->getOperand(0) != LoopID)
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