[llvm] r310910 - [LV] Minor savings to Sink casts to unravel first order recurrence
Ayal Zaks via llvm-commits
llvm-commits at lists.llvm.org
Tue Aug 15 01:33:00 PDT 2017
Author: ayalz
Date: Tue Aug 15 01:32:59 2017
New Revision: 310910
URL: http://llvm.org/viewvc/llvm-project?rev=310910&view=rev
Log:
[LV] Minor savings to Sink casts to unravel first order recurrence
Two minor savings: avoid copying the SinkAfter map and avoid moving a cast if it
is not needed.
Differential Revision: https://reviews.llvm.org/D36408
Modified:
llvm/trunk/lib/Transforms/Utils/LoopUtils.cpp
llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp
llvm/trunk/test/Transforms/LoopVectorize/first-order-recurrence.ll
Modified: llvm/trunk/lib/Transforms/Utils/LoopUtils.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/LoopUtils.cpp?rev=310910&r1=310909&r2=310910&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/LoopUtils.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/LoopUtils.cpp Tue Aug 15 01:32:59 2017
@@ -565,7 +565,8 @@ bool RecurrenceDescriptor::isFirstOrderR
auto *I = Phi->user_back();
if (I->isCast() && (I->getParent() == Phi->getParent()) && I->hasOneUse() &&
DT->dominates(Previous, I->user_back())) {
- SinkAfter[I] = Previous;
+ if (!DT->dominates(Previous, I)) // Otherwise we're good w/o sinking.
+ SinkAfter[I] = Previous;
return true;
}
}
Modified: llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp?rev=310910&r1=310909&r2=310910&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp (original)
+++ llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp Tue Aug 15 01:32:59 2017
@@ -7655,7 +7655,7 @@ void LoopVectorizationPlanner::executePl
// 2. Copy and widen instructions from the old loop into the new loop.
// Move instructions to handle first-order recurrences.
- DenseMap<Instruction *, Instruction *> SinkAfter = Legal->getSinkAfter();
+ DenseMap<Instruction *, Instruction *> &SinkAfter = Legal->getSinkAfter();
for (auto &Entry : SinkAfter) {
Entry.first->removeFromParent();
Entry.first->insertAfter(Entry.second);
Modified: llvm/trunk/test/Transforms/LoopVectorize/first-order-recurrence.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopVectorize/first-order-recurrence.ll?rev=310910&r1=310909&r2=310910&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/LoopVectorize/first-order-recurrence.ll (original)
+++ llvm/trunk/test/Transforms/LoopVectorize/first-order-recurrence.ll Tue Aug 15 01:32:59 2017
@@ -140,7 +140,10 @@ scalar.body:
; CHECK: vector.body:
; CHECK: %vector.recur = phi <4 x i16> [ %vector.recur.init, %vector.ph ], [ [[L1:%[a-zA-Z0-9.]+]], %vector.body ]
; CHECK: [[L1]] = load <4 x i16>
-; CHECK: {{.*}} = shufflevector <4 x i16> %vector.recur, <4 x i16> [[L1]], <4 x i32> <i32 3, i32 4, i32 5, i32 6>
+; CHECK: [[SHUF:%[a-zA-Z0-9.]+]] = shufflevector <4 x i16> %vector.recur, <4 x i16> [[L1]], <4 x i32> <i32 3, i32 4, i32 5, i32 6>
+; Check also that the casts were not moved needlessly.
+; CHECK: sitofp <4 x i16> [[L1]] to <4 x double>
+; CHECK: sitofp <4 x i16> [[SHUF]] to <4 x double>
; CHECK: middle.block:
; CHECK: %vector.recur.extract = extractelement <4 x i16> [[L1]], i32 3
; CHECK: scalar.ph:
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