[MemorySSA & LoopPassManager] Enable MemorySSA as loop dependency. Update tests.

Summary:
I'm not planning to check this in at the moment, but feedback is very welcome, in particular how this affects performance.
The feedback obtains here will guide the next steps towards enabling this.

This patch enables the use of MemorySSA in the loop pass manager.

Passes that currently use MemorySSA:
 - EarlyCSE
Passes that use MemorySSA after this patch:
 - EarlyCSE
 - LICM
 - SimpleLoopUnswitch
Loop passes that update MemorySSA (and do not use it yet, but could use it after this patch):
 - LoopInstSimplify
 - LoopSimplifyCFG
 - LoopUnswitch
 - LoopRotate
 - LoopSimplify
 - LCSSA
Loop passes that do *not* update MemorySSA:
 - IndVarSimplify
 - LoopDelete
 - LoopIdiom
 - LoopSink
 - LoopUnroll
 - LoopInterchange
 - LoopUnrollAndJam
 - LoopVectorize
 - LoopReroll
 - IRCE

Reviewers: chandlerc, george.burgess.iv, davide, sanjoy, gberry

Subscribers: jlebar, Prazek, dmgreen, jdoerfert, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D58311

llvm-svn: 370384

6 files changed, 53 insertions, 38 deletions

diff --git a/llvm/lib/Analysis/MemorySSA.cpp b/llvm/lib/Analysis/MemorySSA.cpp
index 91b2f1d03a1..61aa13cde13 100644
--- a/llvm/lib/Analysis/MemorySSA.cpp
+++ b/llvm/lib/Analysis/MemorySSA.cpp
@@ -84,7 +84,7 @@ bool llvm::VerifyMemorySSA = false;
 #endif
 /// Enables memory ssa as a dependency for loop passes in legacy pass manager.
 cl::opt<bool> llvm::EnableMSSALoopDependency(
-    "enable-mssa-loop-dependency", cl::Hidden, cl::init(false),
+    "enable-mssa-loop-dependency", cl::Hidden, cl::init(true),
     cl::desc("Enable MemorySSA dependency for loop pass manager"));
 
 static cl::opt<bool, true>
diff --git a/llvm/lib/Transforms/Utils/LoopUtils.cpp b/llvm/lib/Transforms/Utils/LoopUtils.cpp
index 4c6c2edc385..b4d7f35d2d9 100644
--- a/llvm/lib/Transforms/Utils/LoopUtils.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUtils.cpp
@@ -19,6 +19,7 @@
 #include "llvm/Analysis/InstructionSimplify.h"
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/Analysis/LoopPass.h"
+#include "llvm/Analysis/MemorySSA.h"
 #include "llvm/Analysis/MemorySSAUpdater.h"
 #include "llvm/Analysis/MustExecute.h"
 #include "llvm/Analysis/ScalarEvolution.h"
@@ -170,6 +171,8 @@ void llvm::getLoopAnalysisUsage(AnalysisUsage &AU) {
   AU.addPreserved<SCEVAAWrapperPass>();
   AU.addRequired<ScalarEvolutionWrapperPass>();
   AU.addPreserved<ScalarEvolutionWrapperPass>();
+  // FIXME: When all loop passes preserve MemorySSA, it can be required and
+  // preserved here instead of the individual handling in each pass.
 }
 
 /// Manually defined generic "LoopPass" dependency initialization. This is used
@@ -190,6 +193,7 @@ void llvm::initializeLoopPassPass(PassRegistry &Registry) {
   INITIALIZE_PASS_DEPENDENCY(GlobalsAAWrapperPass)
   INITIALIZE_PASS_DEPENDENCY(SCEVAAWrapperPass)
   INITIALIZE_PASS_DEPENDENCY(ScalarEvolutionWrapperPass)
+  INITIALIZE_PASS_DEPENDENCY(MemorySSAWrapperPass)
 }
 
 /// Create MDNode for input string.
diff --git a/llvm/test/CodeGen/PowerPC/sms-grp-order.ll b/llvm/test/CodeGen/PowerPC/sms-grp-order.ll
index a3e6de1c593..c462e18d9f9 100644
--- a/llvm/test/CodeGen/PowerPC/sms-grp-order.ll
+++ b/llvm/test/CodeGen/PowerPC/sms-grp-order.ll
@@ -4,25 +4,24 @@
 
 define void @lame_encode_buffer_interleaved() local_unnamed_addr {
 ; CHECK-LABEL: lame_encode_buffer_interleaved:
-; CHECK:       # %bb.0:
-; CHECK-NEXT:    lhz 3, 0(0)
-; CHECK-NEXT:    li 5, 1
-; CHECK-NEXT:    sldi 5, 5, 62
-; CHECK-NEXT:    lhz 4, 0(3)
-; CHECK-NEXT:    mtctr 5
-; CHECK-NEXT:    .p2align 5
-; CHECK-NEXT:  .LBB0_1: #
-; CHECK-NEXT:    extsh 3, 3
-; CHECK-NEXT:    extsh 4, 4
-; CHECK-NEXT:    srawi 3, 3, 1
-; CHECK-NEXT:    addze 3, 3
-; CHECK-NEXT:    srawi 4, 4, 1
-; CHECK-NEXT:    addze 4, 4
-; CHECK-NEXT:    bdnz .LBB0_1
-; CHECK-NEXT:  # %bb.2:
-; CHECK-NEXT:    sth 3, 0(0)
-; CHECK-NEXT:    sth 4, 0(3)
-; CHECK-NEXT:    blr
+; CHECK:      # %bb.0:
+; CHECK-NEXT:   lha 3, 0(3)
+; CHECK-NEXT:   li 5, 1
+; CHECK-NEXT:   sldi 5, 5, 62
+; CHECK-NEXT:   lhz 4, 0(0)
+; CHECK-NEXT:   mtctr 5
+; CHECK-NEXT:   srawi 3, 3, 1
+; CHECK-NEXT:   addze 3, 3
+; CHECK-NEXT:   .p2align 4
+; CHECK-NEXT: .LBB0_1:
+; CHECK-NEXT:   extsh 4, 4
+; CHECK-NEXT:   srawi 4, 4, 1
+; CHECK-NEXT:   addze 4, 4
+; CHECK-NEXT:   bdnz .LBB0_1
+; CHECK-NEXT: # %bb.2:
+; CHECK-NEXT:   sth 4, 0(0)
+; CHECK-NEXT:   sth 3, 0(3)
+; CHECK-NEXT:   blr
   br label %1
 
 1:                                                ; preds = %1, %0
diff --git a/llvm/test/Other/opt-O2-pipeline.ll b/llvm/test/Other/opt-O2-pipeline.ll
index ecd6b7c8a35..b4acce3cb8b 100644
--- a/llvm/test/Other/opt-O2-pipeline.ll
+++ b/llvm/test/Other/opt-O2-pipeline.ll
@@ -93,12 +93,13 @@
 ; CHECK-NEXT:         Simplify the CFG
 ; CHECK-NEXT:         Reassociate expressions
 ; CHECK-NEXT:         Dominator Tree Construction
+; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:         Function Alias Analysis Results
+; CHECK-NEXT:         Memory SSA
 ; CHECK-NEXT:         Natural Loop Information
 ; CHECK-NEXT:         Canonicalize natural loops
 ; CHECK-NEXT:         LCSSA Verifier
 ; CHECK-NEXT:         Loop-Closed SSA Form Pass
-; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
-; CHECK-NEXT:         Function Alias Analysis Results
 ; CHECK-NEXT:         Scalar Evolution Analysis
 ; CHECK-NEXT:         Loop Pass Manager
 ; CHECK-NEXT:           Rotate Loops
@@ -153,12 +154,13 @@
 ; CHECK-NEXT:         Phi Values Analysis
 ; CHECK-NEXT:         Memory Dependence Analysis
 ; CHECK-NEXT:         Dead Store Elimination
+; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:         Function Alias Analysis Results
+; CHECK-NEXT:         Memory SSA
 ; CHECK-NEXT:         Natural Loop Information
 ; CHECK-NEXT:         Canonicalize natural loops
 ; CHECK-NEXT:         LCSSA Verifier
 ; CHECK-NEXT:         Loop-Closed SSA Form Pass
-; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
-; CHECK-NEXT:         Function Alias Analysis Results
 ; CHECK-NEXT:         Scalar Evolution Analysis
 ; CHECK-NEXT:         Loop Pass Manager
 ; CHECK-NEXT:           Loop Invariant Code Motion
@@ -185,12 +187,13 @@
 ; CHECK-NEXT:     FunctionPass Manager
 ; CHECK-NEXT:       Float to int
 ; CHECK-NEXT:       Dominator Tree Construction
+; CHECK-NEXT:       Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:       Function Alias Analysis Results
+; CHECK-NEXT:       Memory SSA
 ; CHECK-NEXT:       Natural Loop Information
 ; CHECK-NEXT:       Canonicalize natural loops
 ; CHECK-NEXT:       LCSSA Verifier
 ; CHECK-NEXT:       Loop-Closed SSA Form Pass
-; CHECK-NEXT:       Basic Alias Analysis (stateless AA impl)
-; CHECK-NEXT:       Function Alias Analysis Results
 ; CHECK-NEXT:       Scalar Evolution Analysis
 ; CHECK-NEXT:       Loop Pass Manager
 ; CHECK-NEXT:         Rotate Loops
@@ -246,6 +249,7 @@
 ; CHECK-NEXT:       Lazy Block Frequency Analysis
 ; CHECK-NEXT:       Optimization Remark Emitter
 ; CHECK-NEXT:       Combine redundant instructions
+; CHECK-NEXT:       Memory SSA
 ; CHECK-NEXT:       Canonicalize natural loops
 ; CHECK-NEXT:       LCSSA Verifier
 ; CHECK-NEXT:       Loop-Closed SSA Form Pass
diff --git a/llvm/test/Other/opt-O3-pipeline.ll b/llvm/test/Other/opt-O3-pipeline.ll
index ee5e55f0d37..b1f68aed302 100644
--- a/llvm/test/Other/opt-O3-pipeline.ll
+++ b/llvm/test/Other/opt-O3-pipeline.ll
@@ -98,12 +98,13 @@
 ; CHECK-NEXT:         Simplify the CFG
 ; CHECK-NEXT:         Reassociate expressions
 ; CHECK-NEXT:         Dominator Tree Construction
+; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:         Function Alias Analysis Results
+; CHECK-NEXT:         Memory SSA
 ; CHECK-NEXT:         Natural Loop Information
 ; CHECK-NEXT:         Canonicalize natural loops
 ; CHECK-NEXT:         LCSSA Verifier
 ; CHECK-NEXT:         Loop-Closed SSA Form Pass
-; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
-; CHECK-NEXT:         Function Alias Analysis Results
 ; CHECK-NEXT:         Scalar Evolution Analysis
 ; CHECK-NEXT:         Loop Pass Manager
 ; CHECK-NEXT:           Rotate Loops
@@ -158,12 +159,13 @@
 ; CHECK-NEXT:         Phi Values Analysis
 ; CHECK-NEXT:         Memory Dependence Analysis
 ; CHECK-NEXT:         Dead Store Elimination
+; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:         Function Alias Analysis Results
+; CHECK-NEXT:         Memory SSA
 ; CHECK-NEXT:         Natural Loop Information
 ; CHECK-NEXT:         Canonicalize natural loops
 ; CHECK-NEXT:         LCSSA Verifier
 ; CHECK-NEXT:         Loop-Closed SSA Form Pass
-; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
-; CHECK-NEXT:         Function Alias Analysis Results
 ; CHECK-NEXT:         Scalar Evolution Analysis
 ; CHECK-NEXT:         Loop Pass Manager
 ; CHECK-NEXT:           Loop Invariant Code Motion
@@ -190,12 +192,13 @@
 ; CHECK-NEXT:     FunctionPass Manager
 ; CHECK-NEXT:       Float to int
 ; CHECK-NEXT:       Dominator Tree Construction
+; CHECK-NEXT:       Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:       Function Alias Analysis Results
+; CHECK-NEXT:       Memory SSA
 ; CHECK-NEXT:       Natural Loop Information
 ; CHECK-NEXT:       Canonicalize natural loops
 ; CHECK-NEXT:       LCSSA Verifier
 ; CHECK-NEXT:       Loop-Closed SSA Form Pass
-; CHECK-NEXT:       Basic Alias Analysis (stateless AA impl)
-; CHECK-NEXT:       Function Alias Analysis Results
 ; CHECK-NEXT:       Scalar Evolution Analysis
 ; CHECK-NEXT:       Loop Pass Manager
 ; CHECK-NEXT:         Rotate Loops
@@ -251,6 +254,7 @@
 ; CHECK-NEXT:       Lazy Block Frequency Analysis
 ; CHECK-NEXT:       Optimization Remark Emitter
 ; CHECK-NEXT:       Combine redundant instructions
+; CHECK-NEXT:       Memory SSA
 ; CHECK-NEXT:       Canonicalize natural loops
 ; CHECK-NEXT:       LCSSA Verifier
 ; CHECK-NEXT:       Loop-Closed SSA Form Pass
diff --git a/llvm/test/Other/opt-Os-pipeline.ll b/llvm/test/Other/opt-Os-pipeline.ll
index 069d198c7a1..b9902685b88 100644
--- a/llvm/test/Other/opt-Os-pipeline.ll
+++ b/llvm/test/Other/opt-Os-pipeline.ll
@@ -80,12 +80,13 @@
 ; CHECK-NEXT:         Simplify the CFG
 ; CHECK-NEXT:         Reassociate expressions
 ; CHECK-NEXT:         Dominator Tree Construction
+; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:         Function Alias Analysis Results
+; CHECK-NEXT:         Memory SSA
 ; CHECK-NEXT:         Natural Loop Information
 ; CHECK-NEXT:         Canonicalize natural loops
 ; CHECK-NEXT:         LCSSA Verifier
 ; CHECK-NEXT:         Loop-Closed SSA Form Pass
-; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
-; CHECK-NEXT:         Function Alias Analysis Results
 ; CHECK-NEXT:         Scalar Evolution Analysis
 ; CHECK-NEXT:         Loop Pass Manager
 ; CHECK-NEXT:           Rotate Loops
@@ -140,12 +141,13 @@
 ; CHECK-NEXT:         Phi Values Analysis
 ; CHECK-NEXT:         Memory Dependence Analysis
 ; CHECK-NEXT:         Dead Store Elimination
+; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:         Function Alias Analysis Results
+; CHECK-NEXT:         Memory SSA
 ; CHECK-NEXT:         Natural Loop Information
 ; CHECK-NEXT:         Canonicalize natural loops
 ; CHECK-NEXT:         LCSSA Verifier
 ; CHECK-NEXT:         Loop-Closed SSA Form Pass
-; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
-; CHECK-NEXT:         Function Alias Analysis Results
 ; CHECK-NEXT:         Scalar Evolution Analysis
 ; CHECK-NEXT:         Loop Pass Manager
 ; CHECK-NEXT:           Loop Invariant Code Motion
@@ -172,12 +174,13 @@
 ; CHECK-NEXT:     FunctionPass Manager
 ; CHECK-NEXT:       Float to int
 ; CHECK-NEXT:       Dominator Tree Construction
+; CHECK-NEXT:       Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:       Function Alias Analysis Results
+; CHECK-NEXT:       Memory SSA
 ; CHECK-NEXT:       Natural Loop Information
 ; CHECK-NEXT:       Canonicalize natural loops
 ; CHECK-NEXT:       LCSSA Verifier
 ; CHECK-NEXT:       Loop-Closed SSA Form Pass
-; CHECK-NEXT:       Basic Alias Analysis (stateless AA impl)
-; CHECK-NEXT:       Function Alias Analysis Results
 ; CHECK-NEXT:       Scalar Evolution Analysis
 ; CHECK-NEXT:       Loop Pass Manager
 ; CHECK-NEXT:         Rotate Loops
@@ -233,6 +236,7 @@
 ; CHECK-NEXT:       Lazy Block Frequency Analysis
 ; CHECK-NEXT:       Optimization Remark Emitter
 ; CHECK-NEXT:       Combine redundant instructions
+; CHECK-NEXT:       Memory SSA
 ; CHECK-NEXT:       Canonicalize natural loops
 ; CHECK-NEXT:       LCSSA Verifier
 ; CHECK-NEXT:       Loop-Closed SSA Form Pass