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-rw-r--r--llvm/lib/Transforms/Utils/LCSSA.cpp11
-rw-r--r--llvm/lib/Transforms/Utils/LoopSimplify.cpp62
-rw-r--r--llvm/test/Transforms/LCSSA/pr28424.ll87
-rw-r--r--llvm/test/Transforms/LoopSimplify/pr28272.ll76
4 files changed, 13 insertions, 223 deletions
diff --git a/llvm/lib/Transforms/Utils/LCSSA.cpp b/llvm/lib/Transforms/Utils/LCSSA.cpp
index bee6e24d25a..9658966779b 100644
--- a/llvm/lib/Transforms/Utils/LCSSA.cpp
+++ b/llvm/lib/Transforms/Utils/LCSSA.cpp
@@ -115,8 +115,7 @@ bool llvm::formLCSSAForInstructions(SmallVectorImpl<Instruction *> &Worklist,
SmallVector<PHINode *, 16> AddedPHIs;
SmallVector<PHINode *, 8> PostProcessPHIs;
- SmallVector<PHINode *, 4> InsertedPHIs;
- SSAUpdater SSAUpdate(&InsertedPHIs);
+ SSAUpdater SSAUpdate;
SSAUpdate.Initialize(I->getType(), I->getName());
// Insert the LCSSA phi's into all of the exit blocks dominated by the
@@ -185,14 +184,6 @@ bool llvm::formLCSSAForInstructions(SmallVectorImpl<Instruction *> &Worklist,
// Otherwise, do full PHI insertion.
SSAUpdate.RewriteUse(*UseToRewrite);
-
- // SSAUpdater might have inserted phi-nodes inside other loops. We'll need
- // to post-process them to keep LCSSA form.
- for (PHINode *InsertedPN : InsertedPHIs) {
- if (auto *OtherLoop = LI.getLoopFor(InsertedPN->getParent()))
- if (!L->contains(OtherLoop))
- PostProcessPHIs.push_back(InsertedPN);
- }
}
// Post process PHI instructions that were inserted into another disjoint
diff --git a/llvm/lib/Transforms/Utils/LoopSimplify.cpp b/llvm/lib/Transforms/Utils/LoopSimplify.cpp
index 2846e8f235b..b3a928bf775 100644
--- a/llvm/lib/Transforms/Utils/LoopSimplify.cpp
+++ b/llvm/lib/Transforms/Utils/LoopSimplify.cpp
@@ -327,8 +327,6 @@ static Loop *separateNestedLoop(Loop *L, BasicBlock *Preheader,
else
NewOuter->addChildLoop(L->removeChildLoop(SubLoops.begin() + I));
- SmallVector<BasicBlock *, 8> OuterLoopBlocks;
- OuterLoopBlocks.push_back(NewBB);
// Now that we know which blocks are in L and which need to be moved to
// OuterLoop, move any blocks that need it.
for (unsigned i = 0; i != L->getBlocks().size(); ++i) {
@@ -336,53 +334,12 @@ static Loop *separateNestedLoop(Loop *L, BasicBlock *Preheader,
if (!BlocksInL.count(BB)) {
// Move this block to the parent, updating the exit blocks sets
L->removeBlockFromLoop(BB);
- if ((*LI)[BB] == L) {
+ if ((*LI)[BB] == L)
LI->changeLoopFor(BB, NewOuter);
- OuterLoopBlocks.push_back(BB);
- }
--i;
}
}
- // Split edges to exit blocks from the inner loop, if they emerged in the
- // process of separating the outer one.
- SmallVector<BasicBlock *, 8> ExitBlocks;
- L->getExitBlocks(ExitBlocks);
- SmallSetVector<BasicBlock *, 8> ExitBlockSet(ExitBlocks.begin(),
- ExitBlocks.end());
- for (BasicBlock *ExitBlock : ExitBlockSet) {
- if (any_of(predecessors(ExitBlock),
- [L](BasicBlock *BB) { return !L->contains(BB); })) {
- rewriteLoopExitBlock(L, ExitBlock, DT, LI, PreserveLCSSA);
- }
- }
-
- if (PreserveLCSSA) {
- // Fix LCSSA form for L. Some values, which previously were only used inside
- // L, can now be used in NewOuter loop. We need to insert phi-nodes for them
- // in corresponding exit blocks.
-
- // Go through all instructions in OuterLoopBlocks and check if they are
- // using operands from the inner loop. In this case we'll need to fix LCSSA
- // for these instructions.
- SmallSetVector<Instruction *, 8> WorklistSet;
- for (BasicBlock *OuterBB: OuterLoopBlocks) {
- for (Instruction &I : *OuterBB) {
- for (Value *Op : I.operands()) {
- Instruction *OpI = dyn_cast<Instruction>(Op);
- if (!OpI || !L->contains(OpI))
- continue;
- WorklistSet.insert(OpI);
- }
- }
- }
- SmallVector<Instruction *, 8> Worklist(WorklistSet.begin(),
- WorklistSet.end());
- formLCSSAForInstructions(Worklist, *DT, *LI);
- assert(NewOuter->isRecursivelyLCSSAForm(*DT) &&
- "LCSSA is broken after separating nested loops!");
- }
-
return NewOuter;
}
@@ -584,12 +541,17 @@ ReprocessLoop:
SmallSetVector<BasicBlock *, 8> ExitBlockSet(ExitBlocks.begin(),
ExitBlocks.end());
for (BasicBlock *ExitBlock : ExitBlockSet) {
- if (any_of(predecessors(ExitBlock),
- [L](BasicBlock *BB) { return !L->contains(BB); })) {
- rewriteLoopExitBlock(L, ExitBlock, DT, LI, PreserveLCSSA);
- ++NumInserted;
- Changed = true;
- }
+ for (pred_iterator PI = pred_begin(ExitBlock), PE = pred_end(ExitBlock);
+ PI != PE; ++PI)
+ // Must be exactly this loop: no subloops, parent loops, or non-loop preds
+ // allowed.
+ if (!L->contains(*PI)) {
+ if (rewriteLoopExitBlock(L, ExitBlock, DT, LI, PreserveLCSSA)) {
+ ++NumInserted;
+ Changed = true;
+ }
+ break;
+ }
}
// If the header has more than two predecessors at this point (from the
diff --git a/llvm/test/Transforms/LCSSA/pr28424.ll b/llvm/test/Transforms/LCSSA/pr28424.ll
deleted file mode 100644
index cd7969009fb..00000000000
--- a/llvm/test/Transforms/LCSSA/pr28424.ll
+++ /dev/null
@@ -1,87 +0,0 @@
-; RUN: opt < %s -lcssa -S -o - | FileCheck %s
-target triple = "x86_64-unknown-linux-gnu"
-
-; PR28424
-; Here LCSSA adds phi-nodes for %x into the loop exits. Then, SSAUpdater needs
-; to insert phi-nodes to merge these values. That creates a new def, which in
-; its turn needs another LCCSA phi-node, and this test ensures that we insert
-; it.
-
-; CHECK-LABEL: @foo1
-define internal i32 @foo1() {
-entry:
- br label %header
-
-header:
- %x = add i32 0, 1
- br i1 undef, label %if, label %loopexit1
-
-if:
- br i1 undef, label %latch, label %loopexit2
-
-latch:
- br i1 undef, label %header, label %loopexit3
-
-; CHECK: loopexit1:
-; CHECK: %x.lcssa = phi i32 [ %x, %header ]
-loopexit1:
- br label %loop_with_insert_point
-
-; CHECK: loopexit2:
-; CHECK: %x.lcssa1 = phi i32 [ %x, %if ]
-loopexit2:
- br label %exit
-
-; CHECK: loopexit3:
-; CHECK: %x.lcssa2 = phi i32 [ %x, %latch ]
-loopexit3:
- br label %loop_with_insert_point
-
-; CHECK: loop_with_insert_point:
-; CHECK: %x4 = phi i32 [ %x4, %loop_with_insert_point ], [ %x.lcssa2, %loopexit3 ], [ %x.lcssa, %loopexit1 ]
-loop_with_insert_point:
- br i1 undef, label %loop_with_insert_point, label %bb
-
-; CHECK: bb:
-; CHECK: %x4.lcssa = phi i32 [ %x4, %loop_with_insert_point ]
-bb:
- br label %exit
-
-; CHECK: exit:
-; CHECK: %x3 = phi i32 [ %x4.lcssa, %bb ], [ %x.lcssa1, %loopexit2 ]
-exit:
- ret i32 %x
-}
-
-; CHECK-LABEL: @foo2
-define internal i32 @foo2() {
-entry:
- br label %header
-
-header:
- %x = add i32 0, 1
- br i1 undef, label %latch, label %loopexit1
-
-latch:
- br i1 undef, label %header, label %loopexit2
-
-; CHECK: loopexit1:
-; CHECK: %x.lcssa = phi i32 [ %x, %header ]
-loopexit1:
- br label %loop_with_insert_point
-
-; CHECK: loopexit2:
-; CHECK: %x.lcssa1 = phi i32 [ %x, %latch ]
-loopexit2:
- br label %loop_with_insert_point
-
-; CHECK: loop_with_insert_point:
-; CHECK: %x2 = phi i32 [ %x2, %loop_with_insert_point ], [ %x.lcssa1, %loopexit2 ], [ %x.lcssa, %loopexit1 ]
-loop_with_insert_point:
- br i1 undef, label %loop_with_insert_point, label %exit
-
-; CHECK: exit:
-; CHECK: %x2.lcssa = phi i32 [ %x2, %loop_with_insert_point ]
-exit:
- ret i32 %x
-}
diff --git a/llvm/test/Transforms/LoopSimplify/pr28272.ll b/llvm/test/Transforms/LoopSimplify/pr28272.ll
deleted file mode 100644
index 49990f92cab..00000000000
--- a/llvm/test/Transforms/LoopSimplify/pr28272.ll
+++ /dev/null
@@ -1,76 +0,0 @@
-; RUN: opt < %s -lcssa -loop-unroll -S | FileCheck %s
-target triple = "x86_64-unknown-linux-gnu"
-
-; PR28272
-; When LoopSimplify separates nested loops, it might break LCSSA form: values
-; from the original loop might be used in the outer loop. This test invokes
-; loop-unroll, which calls loop-simplify before itself. If LCSSA is broken
-; after loop-simplify, we crash on assertion.
-
-; CHECK-LABEL: @foo
-define void @foo() {
-entry:
- br label %header
-
-header:
- br label %loop1
-
-loop1:
- br i1 true, label %loop1, label %bb43
-
-bb43:
- %a = phi i32 [ undef, %loop1 ], [ 0, %bb45 ], [ %a, %bb54 ]
- %b = phi i32 [ 0, %loop1 ], [ 1, %bb54 ], [ %c, %bb45 ]
- br i1 true, label %bb114, label %header
-
-bb114:
- %c = add i32 0, 1
- %d = add i32 0, 1
- br i1 true, label %bb45, label %bb54
-
-bb45:
- %x = add i32 %d, 0
- br label %bb43
-
-bb54:
- br label %bb43
-}
-
-; CHECK-LABEL: @foo2
-define void @foo2() {
-entry:
- br label %outer
-
-outer.loopexit:
- br label %outer
-
-outer:
- br label %loop1
-
-loop1:
- br i1 true, label %loop1, label %loop2.preheader
-
-loop2.preheader:
- %a.ph = phi i32 [ undef, %loop1 ]
- %b.ph = phi i32 [ 0, %loop1 ]
- br label %loop2
-
-loop2:
- %a = phi i32 [ 0, %loop2.if.true ], [ %a, %loop2.if.false ], [ %a.ph, %loop2.preheader ], [0, %bb]
- %b = phi i32 [ 1, %loop2.if.false ], [ %c, %loop2.if.true ], [ %b.ph, %loop2.preheader ], [%c, %bb]
- br i1 true, label %loop2.if, label %outer.loopexit
-
-loop2.if:
- %c = add i32 0, 1
- switch i32 undef, label %loop2.if.false [i32 0, label %loop2.if.true
- i32 1, label %bb]
-
-loop2.if.true:
- br i1 undef, label %loop2, label %bb
-
-loop2.if.false:
- br label %loop2
-
-bb:
- br label %loop2
-}
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