[llvm] r293124 - [LoopUnroll] Properly update loopinfo for runtime unrolling by 2
Michael Kuperstein via llvm-commits
llvm-commits at lists.llvm.org
Wed Jan 25 17:04:12 PST 2017
Author: mkuper
Date: Wed Jan 25 19:04:11 2017
New Revision: 293124
URL: http://llvm.org/viewvc/llvm-project?rev=293124&view=rev
Log:
[LoopUnroll] Properly update loopinfo for runtime unrolling by 2
Even when we don't create a remainder loop (that is, when we unroll by 2), we
may duplicate nested loops into the remainder. This is complicated by the fact
the remainder may itself be either inserted into an outer loop, or at the top
level. In the latter case, we may need to create new top-level loops.
Differential Revision: https://reviews.llvm.org/D29156
Added:
llvm/trunk/test/Transforms/LoopUnroll/runtime-li.ll
Modified:
llvm/trunk/lib/Transforms/Scalar/LoopUnrollPass.cpp
llvm/trunk/lib/Transforms/Utils/LoopUnroll.cpp
llvm/trunk/lib/Transforms/Utils/LoopUnrollRuntime.cpp
llvm/trunk/test/Transforms/LoopUnroll/revisit.ll
Modified: llvm/trunk/lib/Transforms/Scalar/LoopUnrollPass.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LoopUnrollPass.cpp?rev=293124&r1=293123&r2=293124&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LoopUnrollPass.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LoopUnrollPass.cpp Wed Jan 25 19:04:11 2017
@@ -1160,7 +1160,8 @@ PreservedAnalyses LoopUnrollPass::run(Lo
#endif
// Unrolling can do several things to introduce new loops into a loop nest:
- // - Partial unrolling clones child loops within the current loop.
+ // - Partial unrolling clones child loops within the current loop. If it
+ // uses a remainder, then it can also create any number of sibling loops.
// - Full unrolling clones child loops within the current loop but then
// removes the current loop making all of the children appear to be new
// sibling loops.
Modified: llvm/trunk/lib/Transforms/Utils/LoopUnroll.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/LoopUnroll.cpp?rev=293124&r1=293123&r2=293124&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/LoopUnroll.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/LoopUnroll.cpp Wed Jan 25 19:04:11 2017
@@ -199,11 +199,14 @@ const Loop* llvm::addClonedBlockToLoopIn
assert(OriginalBB == OldLoop->getHeader() &&
"Header should be first in RPO");
+ NewLoop = new Loop();
Loop *NewLoopParent = NewLoops.lookup(OldLoop->getParentLoop());
- assert(NewLoopParent &&
- "Expected parent loop before sub-loop in RPO");
- NewLoop = new Loop;
- NewLoopParent->addChildLoop(NewLoop);
+
+ if (NewLoopParent)
+ NewLoopParent->addChildLoop(NewLoop);
+ else
+ LI->addTopLevelLoop(NewLoop);
+
NewLoop->addBasicBlockToLoop(ClonedBB, *LI);
return OldLoop;
} else {
Modified: llvm/trunk/lib/Transforms/Utils/LoopUnrollRuntime.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/LoopUnrollRuntime.cpp?rev=293124&r1=293123&r2=293124&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/LoopUnrollRuntime.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/LoopUnrollRuntime.cpp Wed Jan 25 19:04:11 2017
@@ -311,17 +311,22 @@ static void CloneLoopBlocks(Loop *L, Val
}
NewLoopsMap NewLoops;
- NewLoops[L] = NewLoop;
+ if (NewLoop)
+ NewLoops[L] = NewLoop;
+ else if (ParentLoop)
+ NewLoops[L] = ParentLoop;
+
// For each block in the original loop, create a new copy,
// and update the value map with the newly created values.
for (LoopBlocksDFS::RPOIterator BB = BlockBegin; BB != BlockEnd; ++BB) {
BasicBlock *NewBB = CloneBasicBlock(*BB, VMap, "." + suffix, F);
NewBlocks.push_back(NewBB);
-
- if (NewLoop) {
+
+ // If we're unrolling the outermost loop, there's no remainder loop,
+ // and this block isn't in a nested loop, then the new block is not
+ // in any loop. Otherwise, add it to loopinfo.
+ if (CreateRemainderLoop || LI->getLoopFor(*BB) != L || ParentLoop)
addClonedBlockToLoopInfo(*BB, NewBB, LI, NewLoops);
- } else if (ParentLoop)
- ParentLoop->addBasicBlockToLoop(NewBB, *LI);
VMap[*BB] = NewBB;
if (Header == *BB) {
Modified: llvm/trunk/test/Transforms/LoopUnroll/revisit.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/revisit.ll?rev=293124&r1=293123&r2=293124&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/LoopUnroll/revisit.ll (original)
+++ llvm/trunk/test/Transforms/LoopUnroll/revisit.ll Wed Jan 25 19:04:11 2017
@@ -123,7 +123,7 @@ l0.0.latch:
; CHECK: LoopUnrollPass on Loop at depth 2 containing: %l0.0
; CHECK-NOT: LoopUnrollPass
;
-; Partial unrolling occurs which introduces new child loops but not new sibling
+; Partial unrolling occurs which introduces both new child loops and new sibling
; loops. We only visit the child loops in a special mode, not by default.
; CHECK-CHILDREN: LoopUnrollPass on Loop at depth 3 containing: %l0.0.0<header>
; CHECK-CHILDREN-NOT: LoopUnrollPass
@@ -137,7 +137,13 @@ l0.0.latch:
; When we revisit children, we also revisit the current loop.
; CHECK-CHILDREN: LoopUnrollPass on Loop at depth 2 containing: %l0.0<header>
; CHECK-CHILDREN-NOT: LoopUnrollPass
-
+;
+; Revisit the children of the outer loop that are part of the prologue.
+;
+; CHECK: LoopUnrollPass on Loop at depth 2 containing: %l0.0.0.prol<header>
+; CHECK-NOT: LoopUnrollPass
+; CHECK: LoopUnrollPass on Loop at depth 2 containing: %l0.0.1.prol<header>
+; CHECK-NOT: LoopUnrollPass
l0.latch:
br label %l0
; CHECK: LoopUnrollPass on Loop at depth 1 containing: %l0<header>
Added: llvm/trunk/test/Transforms/LoopUnroll/runtime-li.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/runtime-li.ll?rev=293124&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/LoopUnroll/runtime-li.ll (added)
+++ llvm/trunk/test/Transforms/LoopUnroll/runtime-li.ll Wed Jan 25 19:04:11 2017
@@ -0,0 +1,36 @@
+; RUN: opt -S -loop-unroll -unroll-runtime -unroll-count=2 -verify-loop-info -pass-remarks=loop-unroll < %s 2>&1 | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Verify that runtime-unrolling a top-level loop that has nested loops does not
+; make the unroller produce invalid loop-info.
+; CHECK: remark: {{.*}}: unrolled loop by a factor of 2 with run-time trip count
+; CHECK: @widget
+; CHECK: ret void
+define void @widget(double* %arg, double* %arg1, double* %p, i64* %q1, i64* %q2) local_unnamed_addr {
+entry:
+ br label %header.outer
+
+header.outer: ; preds = %latch.outer, %entry
+ %tmp = phi double* [ %tmp8, %latch.outer ], [ %arg, %entry ]
+ br label %header.inner
+
+header.inner: ; preds = %latch.inner, %header.outer
+ br i1 undef, label %latch.inner, label %latch.outer
+
+latch.inner: ; preds = %header.inner
+ %tmp5 = load i64, i64* %q1, align 8
+ store i64 %tmp5, i64* %q2, align 8
+ %tmp6 = icmp eq double* %p, %arg
+ br label %header.inner
+
+latch.outer: ; preds = %header.inner
+ store double 0.0, double* %p, align 8
+ %tmp8 = getelementptr inbounds double, double* %tmp, i64 1
+ %tmp9 = icmp eq double* %tmp8, %arg1
+ br i1 %tmp9, label %exit, label %header.outer
+
+exit: ; preds = %latch.outer
+ ret void
+}
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