From 6419f6461cfc8e741fb9b79971d961d1c07986f3 Mon Sep 17 00:00:00 2001
From: Sanjoy Das <sanjoy@playingwithpointers.com>
Date: Wed, 4 Oct 2017 22:02:27 +0000
Subject: [PATCH] Do not call Loop::getName on possibly dead loops

This fixes PR34832.

llvm-svn: 314938
---
 lib/Analysis/LoopAnalysisManager.cpp |  6 ++++--
 test/Other/loop-pm-invalidation.ll   | 16 ++++++++--------
 2 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/lib/Analysis/LoopAnalysisManager.cpp b/lib/Analysis/LoopAnalysisManager.cpp
index 84a891c3f4f..7647f85019d 100644
--- a/lib/Analysis/LoopAnalysisManager.cpp
+++ b/lib/Analysis/LoopAnalysisManager.cpp
@@ -56,8 +56,10 @@ bool LoopAnalysisManagerFunctionProxy::Result::invalidate(
     // analysis manager's cache. So we just walk the keys and forcibly clear
     // those results. Note that the order doesn't matter here as this will just
     // directly destroy the results without calling methods on them.
-    for (Loop *L : PreOrderLoops)
-      InnerAM->clear(*L, L->getName());
+    for (Loop *L : PreOrderLoops) {
+      // NB! `L` may not be in a good enough state to run Loop::getName.
+      InnerAM->clear(*L, "<possibly invalidated loop>");
+    }
 
     // We also need to null out the inner AM so that when the object gets
     // destroyed as invalid we don't try to clear the inner AM again. At that
diff --git a/test/Other/loop-pm-invalidation.ll b/test/Other/loop-pm-invalidation.ll
index d2a0e23a720..9a4f74e1d00 100644
--- a/test/Other/loop-pm-invalidation.ll
+++ b/test/Other/loop-pm-invalidation.ll
@@ -57,7 +57,7 @@ define void @one_loop(i1* %ptr) {
 ; CHECK-LOOP-INV-NEXT: Finished {{.*}}Loop pass manager run.
 ; CHECK-LOOP-INV-NEXT: Running pass: InvalidateAnalysisPass<{{.*}}LoopAnalysis
 ; CHECK-LOOP-INV-NEXT: Invalidating all non-preserved analyses
-; CHECK-LOOP-INV-NEXT: Clearing all analysis results for: l0.header
+; CHECK-LOOP-INV-NEXT: Clearing all analysis results for: <possibly invalidated loop>
 ; CHECK-LOOP-INV-NEXT: Invalidating analysis: LoopAnalysis
 ; CHECK-LOOP-INV-NEXT: Invalidating analysis: ScalarEvolutionAnalysis
 ; CHECK-LOOP-INV-NEXT: Invalidating analysis: InnerAnalysisManagerProxy<{{.*}}Loop
@@ -84,7 +84,7 @@ define void @one_loop(i1* %ptr) {
 ; CHECK-SCEV-INV-NEXT: Finished {{.*}}Loop pass manager run.
 ; CHECK-SCEV-INV-NEXT: Running pass: InvalidateAnalysisPass<{{.*}}ScalarEvolutionAnalysis
 ; CHECK-SCEV-INV-NEXT: Invalidating all non-preserved analyses
-; CHECK-SCEV-INV-NEXT: Clearing all analysis results for: l0.header
+; CHECK-SCEV-INV-NEXT: Clearing all analysis results for: <possibly invalidated loop>
 ; CHECK-SCEV-INV-NEXT: Invalidating analysis: ScalarEvolutionAnalysis
 ; CHECK-SCEV-INV-NEXT: Invalidating analysis: InnerAnalysisManagerProxy<{{.*}}Loop
 ; CHECK-SCEV-INV-NEXT: Running pass: FunctionToLoopPassAdaptor<{{.*}}> on one_loop
@@ -124,8 +124,8 @@ define void @nested_loops(i1* %ptr) {
 ; CHECK-LOOP-INV: Finished {{.*}}Loop pass manager run.
 ; CHECK-LOOP-INV-NEXT: Running pass: InvalidateAnalysisPass<{{.*}}LoopAnalysis
 ; CHECK-LOOP-INV-NEXT: Invalidating all non-preserved analyses
-; CHECK-LOOP-INV-NEXT: Clearing all analysis results for: l.0.header
-; CHECK-LOOP-INV-NEXT: Clearing all analysis results for: l.0.0.header
+; CHECK-LOOP-INV-NEXT: Clearing all analysis results for: <possibly invalidated loop>
+; CHECK-LOOP-INV-NEXT: Clearing all analysis results for: <possibly invalidated loop>
 ; CHECK-LOOP-INV-NEXT: Invalidating analysis: LoopAnalysis
 ; CHECK-LOOP-INV-NEXT: Invalidating analysis: ScalarEvolutionAnalysis
 ; CHECK-LOOP-INV-NEXT: Invalidating analysis: InnerAnalysisManagerProxy<{{.*}}Loop
@@ -158,8 +158,8 @@ define void @nested_loops(i1* %ptr) {
 ; CHECK-SCEV-INV: Finished {{.*}}Loop pass manager run.
 ; CHECK-SCEV-INV-NEXT: Running pass: InvalidateAnalysisPass<{{.*}}ScalarEvolutionAnalysis
 ; CHECK-SCEV-INV-NEXT: Invalidating all non-preserved analyses
-; CHECK-SCEV-INV-NEXT: Clearing all analysis results for: l.0.header
-; CHECK-SCEV-INV-NEXT: Clearing all analysis results for: l.0.0.header
+; CHECK-SCEV-INV-NEXT: Clearing all analysis results for: <possibly invalidated loop>
+; CHECK-SCEV-INV-NEXT: Clearing all analysis results for: <possibly invalidated loop>
 ; CHECK-SCEV-INV-NEXT: Invalidating analysis: ScalarEvolutionAnalysis
 ; CHECK-SCEV-INV-NEXT: Invalidating analysis: InnerAnalysisManagerProxy<{{.*}}Loop
 ; CHECK-SCEV-INV-NEXT: Running pass: FunctionToLoopPassAdaptor<{{.*}}> on nested_loops
@@ -206,7 +206,7 @@ define void @dead_loop() {
 ; CHECK-LOOP-INV-NEXT: Finished {{.*}}Loop pass manager run.
 ; CHECK-LOOP-INV-NEXT: Running pass: InvalidateAnalysisPass<{{.*}}LoopAnalysis
 ; CHECK-LOOP-INV-NEXT: Invalidating all non-preserved analyses
-; CHECK-LOOP-INV-NEXT: Clearing all analysis results for: l0.header
+; CHECK-LOOP-INV-NEXT: Clearing all analysis results for: <possibly invalidated loop>
 ; CHECK-LOOP-INV-NEXT: Invalidating analysis: LoopAnalysis
 ; CHECK-LOOP-INV-NEXT: Invalidating analysis: ScalarEvolutionAnalysis
 ; CHECK-LOOP-INV-NEXT: Invalidating analysis: InnerAnalysisManagerProxy<{{.*}}Loop
@@ -233,7 +233,7 @@ define void @dead_loop() {
 ; CHECK-SCEV-INV-NEXT: Finished {{.*}}Loop pass manager run.
 ; CHECK-SCEV-INV-NEXT: Running pass: InvalidateAnalysisPass<{{.*}}ScalarEvolutionAnalysis
 ; CHECK-SCEV-INV-NEXT: Invalidating all non-preserved analyses
-; CHECK-SCEV-INV-NEXT: Clearing all analysis results for: l0.header
+; CHECK-SCEV-INV-NEXT: Clearing all analysis results for: <possibly invalidated loop>
 ; CHECK-SCEV-INV-NEXT: Invalidating analysis: ScalarEvolutionAnalysis
 ; CHECK-SCEV-INV-NEXT: Invalidating analysis: InnerAnalysisManagerProxy<{{.*}}Loop
 ; CHECK-SCEV-INV-NEXT: Running pass: FunctionToLoopPassAdaptor<{{.*}}> on dead_loop