Fix the GCC test suite issue exposed by r127477, which was caused by stack

protector insertion not working correctly with unreachable code. Since that
revision was rolled out, this test doesn't actual fail before this fix.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127497 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/StackProtector.cpp b/lib/CodeGen/StackProtector.cpp
index fcaee4208ba3255fe6b36ccdcfea8fa0820521f5..02d8fd6dea9611509ca136084618f9321989c33b 100644 (file)
--- a/lib/CodeGen/StackProtector.cpp
+++ b/lib/CodeGen/StackProtector.cpp
@@ -219,8 +219,8 @@ bool StackProtector::InsertStackProtectors() {
 
     // Split the basic block before the return instruction.
     BasicBlock *NewBB = BB->splitBasicBlock(RI, "SP_return");
-    if (DT) {
-      DT->addNewBlock(NewBB, DT->isReachableFromEntry(BB) ? BB : 0);
+    if (DT && DT->isReachableFromEntry(BB)) {
+      DT->addNewBlock(NewBB, BB);
       FailBBDom = DT->findNearestCommonDominator(FailBBDom, BB);
     }
 
@@ -242,7 +242,7 @@ bool StackProtector::InsertStackProtectors() {
   // statements in the function.
   if (!FailBB) return false;
 
-  if (DT)
+  if (DT && FailBBDom)
     DT->addNewBlock(FailBB, FailBBDom);
 
   return true;

diff --git a/test/CodeGen/X86/unreachable-stack-protector.ll b/test/CodeGen/X86/unreachable-stack-protector.ll
new file mode 100644 (file)
index 0000000..eeebcee
--- /dev/null
+++ b/test/CodeGen/X86/unreachable-stack-protector.ll
@@ -0,0 +1,19 @@
+; RUN: llc < %s | FileCheck %s
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
+target triple = "x86_64-apple-darwin10.0.0"
+
+declare i64 @llvm.objectsize.i64(i8*, i1) nounwind readnone
+
+define void @test5() nounwind optsize noinline ssp {
+entry:
+; CHECK: movq ___stack_chk_guard@GOTPCREL(%rip)
+  %buf = alloca [64 x i8], align 16
+  %0 = call i64 @llvm.objectsize.i64(i8* undef, i1 false)
+  br i1 false, label %if.end, label %if.then
+
+if.then:                                          ; preds = %entry
+  unreachable
+
+if.end:                                           ; preds = %entry
+  ret void
+}