From e982de7be9e190cc2b0ef70a58bceb87d34b511e Mon Sep 17 00:00:00 2001
From: Nuno Lopes <nunoplopes@sapo.pt>
Date: Fri, 27 Jul 2012 18:21:15 +0000
Subject: [PATCH] fix PR13390: do not loop forever with self-referencing self
 instructions

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160876 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Analysis/MemoryBuiltins.cpp        |  8 ++++++++
 test/Transforms/InstCombine/objsize.ll | 19 +++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/lib/Analysis/MemoryBuiltins.cpp b/lib/Analysis/MemoryBuiltins.cpp
index 4833b5212be..c0cc27b6ec5 100644
--- a/lib/Analysis/MemoryBuiltins.cpp
+++ b/lib/Analysis/MemoryBuiltins.cpp
@@ -506,6 +506,10 @@ SizeOffsetType ObjectSizeOffsetVisitor::visitPHINode(PHINode&) {
 }
 
 SizeOffsetType ObjectSizeOffsetVisitor::visitSelectInst(SelectInst &I) {
+  // ignore malformed self-looping selects
+  if (I.getTrueValue() == &I || I.getFalseValue() == &I)
+    return unknown();
+
   SizeOffsetType TrueSide  = compute(I.getTrueValue());
   SizeOffsetType FalseSide = compute(I.getFalseValue());
   if (bothKnown(TrueSide) && bothKnown(FalseSide) && TrueSide == FalseSide)
@@ -711,6 +715,10 @@ SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitPHINode(PHINode &PHI) {
 }
 
 SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitSelectInst(SelectInst &I) {
+  // ignore malformed self-looping selects
+  if (I.getTrueValue() == &I || I.getFalseValue() == &I)
+    return unknown();
+
   SizeOffsetEvalType TrueSide  = compute_(I.getTrueValue());
   SizeOffsetEvalType FalseSide = compute_(I.getFalseValue());
 
diff --git a/test/Transforms/InstCombine/objsize.ll b/test/Transforms/InstCombine/objsize.ll
index 1818d8978dc..dbb0ffcd674 100644
--- a/test/Transforms/InstCombine/objsize.ll
+++ b/test/Transforms/InstCombine/objsize.ll
@@ -219,3 +219,22 @@ define i32 @test13(i8** %esc) {
 ; CHECK: ret i32 8
   ret i32 %1
 }
+
+; CHECK: @PR13390
+define i32 @PR13390(i1 %bool, i8* %a) {
+entry:
+  %cond = or i1 %bool, true
+  br i1 %cond, label %return, label %xpto
+
+xpto:
+  %select = select i1 %bool, i8* %select, i8* %a
+  %select2 = select i1 %bool, i8* %a, i8* %select2
+  %0 = tail call i32 @llvm.objectsize.i32(i8* %select, i1 true)
+  %1 = tail call i32 @llvm.objectsize.i32(i8* %select2, i1 true)
+  %2 = add i32 %0, %1
+; CHECK: ret i32 undef
+  ret i32 %2
+
+return:
+  ret i32 42
+}
-- 
2.34.1