If there are two consecutive llvm.dbg.stoppoint calls then

it is likely that the optimizer deleted code in between these
two intrinsics. Keep only the last llvm.dbg.stoppoint in this case.

llvm-svn: 59657

2 files changed, 60 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
index e2cc8972764..e7d596773f7 100644
--- a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -11966,7 +11966,8 @@ static void AddReachableCodeToWorklist(BasicBlock *BB,
     
     // We have now visited this block!  If we've already been here, ignore it.
     if (!Visited.insert(BB)) continue;
-    
+
+    DbgInfoIntrinsic *DBI_Prev = NULL;
     for (BasicBlock::iterator BBI = BB->begin(), E = BB->end(); BBI != E; ) {
       Instruction *Inst = BBI++;
       
@@ -11987,6 +11988,20 @@ static void AddReachableCodeToWorklist(BasicBlock *BB,
         continue;
       }
      
+      // If there are two consecutive llvm.dbg.stoppoint calls then
+      // it is likely that the optimizer deleted code in between these
+      // two intrinsics. 
+      DbgInfoIntrinsic *DBI_Next = dyn_cast<DbgInfoIntrinsic>(Inst);
+      if (DBI_Next) {
+        if (DBI_Prev
+            && DBI_Prev->getIntrinsicID() == llvm::Intrinsic::dbg_stoppoint
+            && DBI_Next->getIntrinsicID() == llvm::Intrinsic::dbg_stoppoint) {
+          IC.RemoveFromWorkList(DBI_Prev);
+          DBI_Prev->eraseFromParent();
+        }
+        DBI_Prev = DBI_Next;
+      }
+
       IC.AddToWorkList(Inst);
     }
 
diff --git a/llvm/test/DebugInfo/2008-11-19-InstCombine.ll b/llvm/test/DebugInfo/2008-11-19-InstCombine.ll
new file mode 100644
index 00000000000..f99b964ba66
--- /dev/null
+++ b/llvm/test/DebugInfo/2008-11-19-InstCombine.ll
@@ -0,0 +1,44 @@
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep stoppoint | count 3
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
+target triple = "i386-apple-darwin9.5"
+	%llvm.dbg.anchor.type = type { i32, i32 }
+	%llvm.dbg.basictype.type = type { i32, { }*, i8*, { }*, i32, i64, i64, i64, i32, i32 }
+	%llvm.dbg.compile_unit.type = type { i32, { }*, i32, i8*, i8*, i8* }
+	%llvm.dbg.subprogram.type = type { i32, { }*, { }*, i8*, i8*, i8*, { }*, i32, { }*, i1, i1 }
+	%llvm.dbg.variable.type = type { i32, { }*, i8*, { }*, i32, { }* }
+@llvm.dbg.subprogram = internal constant %llvm.dbg.subprogram.type { i32 393262, { }* bitcast (%llvm.dbg.anchor.type* @llvm.dbg.subprograms to { }*), { }* bitcast (%llvm.dbg.compile_unit.type* @llvm.dbg.compile_unit to { }*), i8* getelementptr ([4 x i8]* @.str3, i32 0, i32 0), i8* getelementptr ([4 x i8]* @.str3, i32 0, i32 0), i8* null, { }* bitcast (%llvm.dbg.compile_unit.type* @llvm.dbg.compile_unit to { }*), i32 2, { }* bitcast (%llvm.dbg.basictype.type* @llvm.dbg.basictype to { }*), i1 false, i1 true }, section "llvm.metadata"		; <%llvm.dbg.subprogram.type*> [#uses=1]
+@llvm.dbg.subprograms = linkonce constant %llvm.dbg.anchor.type { i32 393216, i32 46 }, section "llvm.metadata"		; <%llvm.dbg.anchor.type*> [#uses=1]
+@llvm.dbg.compile_unit = internal constant %llvm.dbg.compile_unit.type { i32 393233, { }* bitcast (%llvm.dbg.anchor.type* @llvm.dbg.compile_units to { }*), i32 1, i8* getelementptr ([7 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) }, section "llvm.metadata"		; <%llvm.dbg.compile_unit.type*> [#uses=1]
+@llvm.dbg.compile_units = linkonce constant %llvm.dbg.anchor.type { i32 393216, i32 17 }, section "llvm.metadata"		; <%llvm.dbg.anchor.type*> [#uses=1]
+@.str = internal constant [7 x i8] c"adce.c\00", section "llvm.metadata"		; <[7 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 5623) (LLVM build 00)\00", section "llvm.metadata"		; <[55 x i8]*> [#uses=1]
+@.str3 = internal constant [4 x i8] c"foo\00", section "llvm.metadata"		; <[4 x i8]*> [#uses=1]
+@llvm.dbg.basictype = internal constant %llvm.dbg.basictype.type { i32 393252, { }* bitcast (%llvm.dbg.compile_unit.type* @llvm.dbg.compile_unit to { }*), i8* getelementptr ([4 x i8]* @.str4, i32 0, i32 0), { }* null, i32 0, i64 32, i64 32, i64 0, i32 0, i32 5 }, section "llvm.metadata"		; <%llvm.dbg.basictype.type*> [#uses=1]
+@.str4 = internal constant [4 x i8] c"int\00", section "llvm.metadata"		; <[4 x i8]*> [#uses=1]
+@llvm.dbg.variable = internal constant %llvm.dbg.variable.type { i32 393472, { }* bitcast (%llvm.dbg.subprogram.type* @llvm.dbg.subprogram to { }*), i8* getelementptr ([2 x i8]* @.str5, i32 0, i32 0), { }* bitcast (%llvm.dbg.compile_unit.type* @llvm.dbg.compile_unit to { }*), i32 3, { }* bitcast (%llvm.dbg.basictype.type* @llvm.dbg.basictype to { }*) }, section "llvm.metadata"		; <%llvm.dbg.variable.type*> [#uses=0]
+@.str5 = internal constant [2 x i8] c"i\00", section "llvm.metadata"		; <[2 x i8]*> [#uses=1]
+
+define i32 @foo() nounwind {
+entry:
+	%"alloca point" = bitcast i32 0 to i32		; <i32> [#uses=0]
+	call void @llvm.dbg.func.start({ }* bitcast (%llvm.dbg.subprogram.type* @llvm.dbg.subprogram to { }*))
+	call void @llvm.dbg.stoppoint(i32 3, i32 0, { }* bitcast (%llvm.dbg.compile_unit.type* @llvm.dbg.compile_unit to { }*))
+	call void @llvm.dbg.stoppoint(i32 4, i32 0, { }* bitcast (%llvm.dbg.compile_unit.type* @llvm.dbg.compile_unit to { }*))
+	%0 = mul i32 4, 84		; <i32> [#uses=0]
+	call void @llvm.dbg.stoppoint(i32 5, i32 0, { }* bitcast (%llvm.dbg.compile_unit.type* @llvm.dbg.compile_unit to { }*))
+	br label %return
+
+return:		; preds = %entry
+	call void @llvm.dbg.stoppoint(i32 5, i32 0, { }* bitcast (%llvm.dbg.compile_unit.type* @llvm.dbg.compile_unit to { }*))
+	call void @llvm.dbg.region.end({ }* bitcast (%llvm.dbg.subprogram.type* @llvm.dbg.subprogram to { }*))
+	ret i32 42
+}
+
+declare void @llvm.dbg.func.start({ }*) nounwind
+
+declare void @llvm.dbg.declare({ }*, { }*) nounwind
+
+declare void @llvm.dbg.stoppoint(i32, i32, { }*) nounwind
+
+declare void @llvm.dbg.region.end({ }*) nounwind