From 7a9adc7562c103cc9f501bfc017b5c3b92ef0a06 Mon Sep 17 00:00:00 2001
From: Petar Jovanovic <petar.jovanovic@imgtec.com>
Date: Tue, 1 Mar 2016 16:50:08 +0000
Subject: [PATCH] Revert "calculate builtin_object_size if argument is a
 removable pointer"

Revert r262337 as "check-llvm ubsan" step failed on
sanitizer-x86_64-linux-fast buildbot.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@262349 91177308-0d34-0410-b5e6-96231b3b80d8
---
 .../InstCombine/InstructionCombining.cpp           | 25 ++++------------
 .../InstCombine/builtin-object-size-ptr.ll         | 34 ----------------------
 2 files changed, 6 insertions(+), 53 deletions(-)
 delete mode 100644 test/Transforms/InstCombine/builtin-object-size-ptr.ll

diff --git a/lib/Transforms/InstCombine/InstructionCombining.cpp b/lib/Transforms/InstCombine/InstructionCombining.cpp
index de4dfb5caeb..1b95e9334c1 100644
--- a/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -1942,25 +1942,6 @@ Instruction *InstCombiner::visitAllocSite(Instruction &MI) {
   SmallVector<WeakVH, 64> Users;
   if (isAllocSiteRemovable(&MI, Users, TLI)) {
     for (unsigned i = 0, e = Users.size(); i != e; ++i) {
-      // Lowering all @llvm.objectsize calls first because they may
-      // use a bitcast/GEP of the alloca we are removing.
-      Instruction *I = cast_or_null<Instruction>(&*Users[i]);
-      if (!I) continue;
-
-      if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
-        if (II->getIntrinsicID() == Intrinsic::objectsize) {
-          uint64_t Size;
-          if (!getObjectSize(II->getArgOperand(0), Size, DL, TLI)) {
-            ConstantInt *CI = cast<ConstantInt>(II->getArgOperand(1));
-            Size = CI->isZero() ? -1ULL : 0;
-          }
-          replaceInstUsesWith(*I, ConstantInt::get(I->getType(), Size));
-          eraseInstFromFunction(*I);
-          Users[i] = nullptr; // Skip examining in the next loop.
-        }
-      }
-    }
-    for (unsigned i = 0, e = Users.size(); i != e; ++i) {
       Instruction *I = cast_or_null<Instruction>(&*Users[i]);
       if (!I) continue;
 
@@ -1970,6 +1951,12 @@ Instruction *InstCombiner::visitAllocSite(Instruction &MI) {
                                              C->isFalseWhenEqual()));
       } else if (isa<BitCastInst>(I) || isa<GetElementPtrInst>(I)) {
         replaceInstUsesWith(*I, UndefValue::get(I->getType()));
+      } else if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
+        if (II->getIntrinsicID() == Intrinsic::objectsize) {
+          ConstantInt *CI = cast<ConstantInt>(II->getArgOperand(1));
+          uint64_t DontKnow = CI->isZero() ? -1ULL : 0;
+          replaceInstUsesWith(*I, ConstantInt::get(I->getType(), DontKnow));
+        }
       }
       eraseInstFromFunction(*I);
     }
diff --git a/test/Transforms/InstCombine/builtin-object-size-ptr.ll b/test/Transforms/InstCombine/builtin-object-size-ptr.ll
deleted file mode 100644
index b38513999dc..00000000000
--- a/test/Transforms/InstCombine/builtin-object-size-ptr.ll
+++ /dev/null
@@ -1,34 +0,0 @@
-; RUN: opt -instcombine -S < %s | FileCheck %s
-
-; int foo() {
-; struct V { char buf1[10];
-;            int b;
-;            char buf2[10];
-;           } var;
-;
-;           char *p = &var.buf1[1];
-;           return __builtin_object_size (p, 0);
-; }
-
-%struct.V = type { [10 x i8], i32, [10 x i8] }
-
-define i32 @foo() #0 {
-entry:
-  %var = alloca %struct.V, align 4
-  %0 = bitcast %struct.V* %var to i8*
-  call void @llvm.lifetime.start(i64 28, i8* %0) #3
-  %buf1 = getelementptr inbounds %struct.V, %struct.V* %var, i32 0, i32 0
-  %arrayidx = getelementptr inbounds [10 x i8], [10 x i8]* %buf1, i64 0, i64 1
-  %1 = call i64 @llvm.objectsize.i64.p0i8(i8* %arrayidx, i1 false)
-  %conv = trunc i64 %1 to i32
-  call void @llvm.lifetime.end(i64 28, i8* %0) #3
-  ret i32 %conv
-; CHECK: ret i32 27
-; CHECK-NOT: ret i32 -1
-}
-
-declare void @llvm.lifetime.start(i64, i8* nocapture) #1
-
-declare i64 @llvm.objectsize.i64.p0i8(i8*, i1) #2
-
-declare void @llvm.lifetime.end(i64, i8* nocapture) #1
-- 
2.11.0