Throw an error when stack realignment stuff fails instead of silent

code miscompilation

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86463 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 7 insertions, 3 deletions

diff --git a/lib/Target/X86/X86RegisterInfo.cpp b/lib/Target/X86/X86RegisterInfo.cpp
index c5ff525bdb..63d2821809 100644
--- a/lib/Target/X86/X86RegisterInfo.cpp
+++ b/lib/Target/X86/X86RegisterInfo.cpp
@@ -450,12 +450,16 @@ bool X86RegisterInfo::hasFP(const MachineFunction &MF) const {
 
 bool X86RegisterInfo::needsStackRealignment(const MachineFunction &MF) const {
   const MachineFrameInfo *MFI = MF.getFrameInfo();
+  bool requiresRealignment =
+    RealignStack && (MFI->getMaxAlignment() > StackAlign);
 
   // FIXME: Currently we don't support stack realignment for functions with
   //        variable-sized allocas
-  return (RealignStack &&
-          (MFI->getMaxAlignment() > StackAlign &&
-           !MFI->hasVarSizedObjects()));
+  if (requiresRealignment && MFI->hasVarSizedObjects())
+    llvm_report_error(
+      "Stack realignment in presense of dynamic allocas is not supported");
+
+  return requiresRealignment;
 }
 
 bool X86RegisterInfo::hasReservedCallFrame(MachineFunction &MF) const {