From 65085cf7b3470b7b087f5fd7b0497879b90b32ba Mon Sep 17 00:00:00 2001
From: Devang Patel <dpatel@apple.com>
Date: Wed, 4 Feb 2009 00:03:08 +0000
Subject: [PATCH] Ignore dbg intrinsics while hoisting common code in the two
 blocks up into the branch block.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63687 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Utils/SimplifyCFG.cpp          | 17 ++++++++--
 .../SimplifyCFG/hoist-common-code.dbg.ll      | 33 +++++++++++++++++++
 2 files changed, 47 insertions(+), 3 deletions(-)
 create mode 100644 test/Transforms/SimplifyCFG/hoist-common-code.dbg.ll

diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp
index 9f5df98fc0f..ea68abe22d9 100644
--- a/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -853,7 +853,14 @@ static bool HoistThenElseCodeToIf(BranchInst *BI) {
   BasicBlock *BB1 = BI->getSuccessor(0);  // The true destination.
   BasicBlock *BB2 = BI->getSuccessor(1);  // The false destination
 
-  Instruction *I1 = BB1->begin(), *I2 = BB2->begin();
+  BasicBlock::iterator BB1_Itr = BB1->begin();
+  BasicBlock::iterator BB2_Itr = BB2->begin();
+
+  Instruction *I1 = BB1_Itr++, *I2 = BB2_Itr++;
+  while (isa<DbgInfoIntrinsic>(I1))
+    I1 = BB1_Itr++;
+  while (isa<DbgInfoIntrinsic>(I2))
+    I2 = BB2_Itr++;
   if (I1->getOpcode() != I2->getOpcode() || isa<PHINode>(I1) || 
       isa<InvokeInst>(I1) || !I1->isIdenticalTo(I2))
     return false;
@@ -875,8 +882,12 @@ static bool HoistThenElseCodeToIf(BranchInst *BI) {
       I2->replaceAllUsesWith(I1);
     BB2->getInstList().erase(I2);
 
-    I1 = BB1->begin();
-    I2 = BB2->begin();
+    I1 = BB1_Itr++;
+    while (isa<DbgInfoIntrinsic>(I1))
+      I1 = BB1_Itr++;
+    I2 = BB2_Itr++;
+    while (isa<DbgInfoIntrinsic>(I2))
+      I2 = BB2_Itr++;
   } while (I1->getOpcode() == I2->getOpcode() && I1->isIdenticalTo(I2));
 
   return true;
diff --git a/test/Transforms/SimplifyCFG/hoist-common-code.dbg.ll b/test/Transforms/SimplifyCFG/hoist-common-code.dbg.ll
new file mode 100644
index 00000000000..ad5cd938aba
--- /dev/null
+++ b/test/Transforms/SimplifyCFG/hoist-common-code.dbg.ll
@@ -0,0 +1,33 @@
+; RUN: llvm-as < %s | opt -simplifycfg | llvm-dis | not grep br
+
+
+        %llvm.dbg.anchor.type = type { i32, i32 }
+        %llvm.dbg.compile_unit.type = type { i32, { }*, i32, i8*, i8*, i8*, i1, i1, i8* }
+
+@llvm.dbg.compile_units = linkonce constant %llvm.dbg.anchor.type { i32 458752, i32 17 }, section "llvm.metadata"		; 
+
+@.str = internal constant [4 x i8] c"a.c\00", section "llvm.metadata"		; <[4 x i8]*> [#uses=1]
+@.str1 = internal constant [6 x i8] c"/tmp/\00", section "llvm.metadata"	; <[6 x i8]*> [#uses=1]
+@.str2 = internal constant [55 x i8] c"4.2.1 (Based on Apple Inc. build 5636) (LLVM build 00)\00", section "llvm.metadata"		; <[55 x i8]*> [#uses=1]
+@llvm.dbg.compile_unit = internal constant %llvm.dbg.compile_unit.type { i32 458769, { }* bitcast (%llvm.dbg.anchor.type* @llvm.dbg.compile_units to { }*), i32 1, i8* getelementptr ([4 x i8]* @.str, i32 0, i32 0), i8* getelementptr ([6 x i8]* @.str1, i32 0, i32 0), i8* getelementptr ([55 x i8]* @.str2, i32 0, i32 0), i1 true, i1 false, i8* null }, section "llvm.metadata"		; <%llvm.dbg.compile_unit.type*> [#uses=1]
+
+declare void @llvm.dbg.stoppoint(i32, i32, { }*) nounwind
+
+declare void @bar(i32)
+
+define void @test(i1 %P, i32* %Q) {
+        br i1 %P, label %T, label %F
+T:              ; preds = %0
+call void @llvm.dbg.stoppoint(i32 5, i32 0, { }* bitcast (%llvm.dbg.compile_unit.type* @llvm.dbg.compile_unit to { }*))
+        store i32 1, i32* %Q
+        %A = load i32* %Q               ; <i32> [#uses=1]
+        call void @bar( i32 %A )
+        ret void
+F:              ; preds = %0
+        store i32 1, i32* %Q
+call void @llvm.dbg.stoppoint(i32 5, i32 0, { }* bitcast (%llvm.dbg.compile_unit.type* @llvm.dbg.compile_unit to { }*))
+        %B = load i32* %Q               ; <i32> [#uses=1]
+        call void @bar( i32 %B )
+        ret void
+}
+