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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@109764 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 81e9750..c0f5a40 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -1701,10 +1701,7 @@
   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;