Revert r109652, and remove the offending assert in loadRegFromStackSlot instead.

We do sometimes load from a too small stack slot when dealing with x86 arguments
(varargs and smaller-than-32-bit args). It looks like we know what we are doing
in those cases, so I am going to remove the assert instead of artifically
enlarging stack slot sizes.

The assert in storeRegToStackSlot stays in. We don't want to write beyond the
bounds of a stack slot.

llvm-svn: 109764

2 files changed, 1 insertions, 6 deletions

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 81e9750a408..c0f5a403b9f 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -1701,10 +1701,7 @@ X86TargetLowering::LowerFormalArguments(SDValue Chain,
   if (isVarArg) {
     if (Is64Bit || (CallConv != CallingConv::X86_FastCall &&
                     CallConv != CallingConv::X86_ThisCall)) {
-      // The fixed varargs object is created large enough that we can load and
-      // store any register in it.
-      FuncInfo->setVarArgsFrameIndex(MFI->CreateFixedObject(32, StackSize,
-                                                            true));
+      FuncInfo->setVarArgsFrameIndex(MFI->CreateFixedObject(1, StackSize,true));
     }
     if (Is64Bit) {
       unsigned TotalNumIntRegs = 0, TotalNumXMMRegs = 0;
diff --git a/llvm/lib/Target/X86/X86InstrInfo.cpp b/llvm/lib/Target/X86/X86InstrInfo.cpp
index c4613a28ef4..98323fa7b07 100644
--- a/llvm/lib/Target/X86/X86InstrInfo.cpp
+++ b/llvm/lib/Target/X86/X86InstrInfo.cpp
@@ -2033,8 +2033,6 @@ void X86InstrInfo::loadRegFromStackSlot(MachineBasicBlock &MBB,
                                         const TargetRegisterClass *RC,
                                         const TargetRegisterInfo *TRI) const {
   const MachineFunction &MF = *MBB.getParent();
-  assert(MF.getFrameInfo()->getObjectSize(FrameIdx) >= RC->getSize() &&
-         "Stack slot too small for load");
   bool isAligned = (RI.getStackAlignment() >= 16) || RI.canRealignStack(MF);
   unsigned Opc = getLoadRegOpcode(DestReg, RC, isAligned, TM);
   DebugLoc DL = MBB.findDebugLoc(MI);