[PATCH] D56848: [LCSSA] Skip blocks in sub-loops when scanning for uses.
Florian Hahn via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Fri Jan 18 09:40:23 PST 2019
This revision was automatically updated to reflect the committed changes.
Closed by commit rL351567: [LCSSA] Skip blocks in sub-loops when scanning for uses. (authored by fhahn, committed by ).
Changed prior to commit:
https://reviews.llvm.org/D56848?vs=182381&id=182543#toc
Repository:
rL LLVM
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D56848/new/
https://reviews.llvm.org/D56848
Files:
llvm/trunk/include/llvm/Transforms/Utils/LoopUtils.h
llvm/trunk/lib/Transforms/Utils/LCSSA.cpp
Index: llvm/trunk/lib/Transforms/Utils/LCSSA.cpp
===================================================================
--- llvm/trunk/lib/Transforms/Utils/LCSSA.cpp
+++ llvm/trunk/lib/Transforms/Utils/LCSSA.cpp
@@ -325,6 +325,10 @@
// Look at all the instructions in the loop, checking to see if they have uses
// outside the loop. If so, put them into the worklist to rewrite those uses.
for (BasicBlock *BB : BlocksDominatingExits) {
+ // Skip blocks that are part of any sub-loops, they must be in LCSSA
+ // already.
+ if (LI->getLoopFor(BB) != &L)
+ continue;
for (Instruction &I : *BB) {
// Reject two common cases fast: instructions with no uses (like stores)
// and instructions with one use that is in the same block as this.
Index: llvm/trunk/include/llvm/Transforms/Utils/LoopUtils.h
===================================================================
--- llvm/trunk/include/llvm/Transforms/Utils/LoopUtils.h
+++ llvm/trunk/include/llvm/Transforms/Utils/LoopUtils.h
@@ -79,7 +79,8 @@
///
/// Looks at all instructions in the loop which have uses outside of the
/// current loop. For each, an LCSSA PHI node is inserted and the uses outside
-/// the loop are rewritten to use this node.
+/// the loop are rewritten to use this node. Sub-loops must be in LCSSA form
+/// already.
///
/// LoopInfo and DominatorTree are required and preserved.
///
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