[llvm] r175641 - [ms-inline asm] Make the comment a bit more verbose.

[Chad Rosier]

Author: mcrosier
Date: Wed Feb 20 12:03:44 2013
New Revision: 175641

URL: http://llvm.org/viewvc/llvm-project?rev=175641&view=rev
Log:
[ms-inline asm] Make the comment a bit more verbose.

Modified:
    llvm/trunk/lib/Target/X86/X86RegisterInfo.cpp

Modified: llvm/trunk/lib/Target/X86/X86RegisterInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86RegisterInfo.cpp?rev=175641&r1=175640&r2=175641&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86RegisterInfo.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86RegisterInfo.cpp Wed Feb 20 12:03:44 2013
@@ -389,8 +389,12 @@ bool X86RegisterInfo::hasBasePointer(con
      return false;
 
    // When we need stack realignment and there are dynamic allocas, we can't
-   // reference off of the stack pointer, so we reserve a base pointer.  This
-   // is also true if the function contain MS-style inline assembly.
+   // reference off of the stack pointer, so we reserve a base pointer.
+   //
+   // This is also true if the function contain MS-style inline assembly.  We
+   // do this because if any stack changes occur in the inline assembly, e.g.,
+   // "pusha", then any C local variable or C argument references in the
+   // inline assembly will be wrong because the SP is not properly tracked.
    if ((needsStackRealignment(MF) && MFI->hasVarSizedObjects()) ||
        MF.hasMSInlineAsm())
      return true;