From 17670a995c2cf40e94661b1d21c8bbe3ed742913 Mon Sep 17 00:00:00 2001
From: Devang Patel <dpatel@apple.com>
Date: Thu, 7 Apr 2011 17:27:36 +0000
Subject: [PATCH] While hoisting common code from if/else, hoist debug info
 intrinsics if they match.

llvm-svn: 129078
---
 lib/Transforms/Utils/SimplifyCFG.cpp          | 26 ++++++---
 test/Transforms/SimplifyCFG/hoist-dbgvalue.ll | 53 +++++++++++++++++++
 2 files changed, 71 insertions(+), 8 deletions(-)
 create mode 100644 test/Transforms/SimplifyCFG/hoist-dbgvalue.ll

diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp
index 286b1653494..27f77218f4c 100644
--- a/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -807,10 +807,15 @@ static bool HoistThenElseCodeToIf(BranchInst *BI) {
   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++;
+  // Skip debug info if it is not identical.
+  DbgInfoIntrinsic *DBI1 = dyn_cast<DbgInfoIntrinsic>(I1);
+  DbgInfoIntrinsic *DBI2 = dyn_cast<DbgInfoIntrinsic>(I2);
+  if (!DBI1 || !DBI2 || !DBI1->isIdenticalToWhenDefined(DBI2)) {
+    while (isa<DbgInfoIntrinsic>(I1))
+      I1 = BB1_Itr++;
+    while (isa<DbgInfoIntrinsic>(I2))
+      I2 = BB2_Itr++;
+  }
   if (isa<PHINode>(I1) || !I1->isIdenticalToWhenDefined(I2) ||
       (isa<InvokeInst>(I1) && !isSafeToHoistInvoke(BB1, BB2, I1, I2)))
     return false;
@@ -834,11 +839,16 @@ static bool HoistThenElseCodeToIf(BranchInst *BI) {
     I2->eraseFromParent();
 
     I1 = BB1_Itr++;
-    while (isa<DbgInfoIntrinsic>(I1))
-      I1 = BB1_Itr++;
     I2 = BB2_Itr++;
-    while (isa<DbgInfoIntrinsic>(I2))
-      I2 = BB2_Itr++;
+    // Skip debug info if it is not identical.
+    DbgInfoIntrinsic *DBI1 = dyn_cast<DbgInfoIntrinsic>(I1);
+    DbgInfoIntrinsic *DBI2 = dyn_cast<DbgInfoIntrinsic>(I2);
+    if (!DBI1 || !DBI2 || !DBI1->isIdenticalToWhenDefined(DBI2)) {
+      while (isa<DbgInfoIntrinsic>(I1))
+        I1 = BB1_Itr++;
+      while (isa<DbgInfoIntrinsic>(I2))
+        I2 = BB2_Itr++;
+    }
   } while (I1->isIdenticalToWhenDefined(I2));
 
   return true;
diff --git a/test/Transforms/SimplifyCFG/hoist-dbgvalue.ll b/test/Transforms/SimplifyCFG/hoist-dbgvalue.ll
new file mode 100644
index 00000000000..03053f037d0
--- /dev/null
+++ b/test/Transforms/SimplifyCFG/hoist-dbgvalue.ll
@@ -0,0 +1,53 @@
+; RUN: opt -simplifycfg -S < %s | FileCheck %s
+
+define i32 @foo(i32 %i) nounwind ssp {
+  call void @llvm.dbg.value(metadata !{i32 %i}, i64 0, metadata !6), !dbg !7
+  call void @llvm.dbg.value(metadata !8, i64 0, metadata !9), !dbg !11
+  %1 = icmp ne i32 %i, 0, !dbg !12
+;CHECK: call i32 (...)* @bar()
+;CHECK-NEXT: llvm.dbg.value
+  br i1 %1, label %2, label %4, !dbg !12
+
+; <label>:2                                       ; preds = %0
+  %3 = call i32 (...)* @bar(), !dbg !13
+  call void @llvm.dbg.value(metadata !{i32 %3}, i64 0, metadata !9), !dbg !13
+  br label %6, !dbg !15
+
+; <label>:4                                       ; preds = %0
+  %5 = call i32 (...)* @bar(), !dbg !16
+  call void @llvm.dbg.value(metadata !{i32 %5}, i64 0, metadata !9), !dbg !16
+  br label %6, !dbg !18
+
+; <label>:6                                       ; preds = %4, %2
+  %k.0 = phi i32 [ %3, %2 ], [ %5, %4 ]
+  ret i32 %k.0, !dbg !19
+}
+
+declare void @llvm.dbg.declare(metadata, metadata) nounwind readnone
+
+declare i32 @bar(...)
+
+declare void @llvm.dbg.value(metadata, i64, metadata) nounwind readnone
+
+!llvm.dbg.sp = !{!0}
+
+!0 = metadata !{i32 589870, i32 0, metadata !1, metadata !"foo", metadata !"foo", metadata !"", metadata !1, i32 2, metadata !3, i1 false, i1 true, i32 0, i32 0, i32 0, i32 256, i1 false, i32 (i32)* @foo} ; [ DW_TAG_subprogram ]
+!1 = metadata !{i32 589865, metadata !"b.c", metadata !"/private/tmp", metadata !2} ; [ DW_TAG_file_type ]
+!2 = metadata !{i32 589841, i32 0, i32 12, metadata !"b.c", metadata !"/private/tmp", metadata !"clang", i1 true, i1 false, metadata !"", i32 0} ; [ DW_TAG_compile_unit ]
+!3 = metadata !{i32 589845, metadata !1, metadata !"", metadata !1, i32 0, i64 0, i64 0, i32 0, i32 0, i32 0, metadata !4, i32 0, i32 0} ; [ DW_TAG_subroutine_type ]
+!4 = metadata !{metadata !5}
+!5 = metadata !{i32 589860, metadata !2, metadata !"int", null, i32 0, i64 32, i64 32, i64 0, i32 0, i32 5} ; [ DW_TAG_base_type ]
+!6 = metadata !{i32 590081, metadata !0, metadata !"i", metadata !1, i32 16777218, metadata !5, i32 0} ; [ DW_TAG_arg_variable ]
+!7 = metadata !{i32 2, i32 13, metadata !0, null}
+!8 = metadata !{i32 0}
+!9 = metadata !{i32 590080, metadata !10, metadata !"k", metadata !1, i32 3, metadata !5, i32 0} ; [ DW_TAG_auto_variable ]
+!10 = metadata !{i32 589835, metadata !0, i32 2, i32 16, metadata !1, i32 0} ; [ DW_TAG_lexical_block ]
+!11 = metadata !{i32 3, i32 12, metadata !10, null}
+!12 = metadata !{i32 4, i32 3, metadata !10, null}
+!13 = metadata !{i32 5, i32 5, metadata !14, null}
+!14 = metadata !{i32 589835, metadata !10, i32 4, i32 10, metadata !1, i32 1} ; [ DW_TAG_lexical_block ]
+!15 = metadata !{i32 6, i32 3, metadata !14, null}
+!16 = metadata !{i32 7, i32 5, metadata !17, null}
+!17 = metadata !{i32 589835, metadata !10, i32 6, i32 10, metadata !1, i32 2} ; [ DW_TAG_lexical_block ]
+!18 = metadata !{i32 8, i32 3, metadata !17, null}
+!19 = metadata !{i32 9, i32 3, metadata !10, null}