[ms-inline asm] Force the use of a base pointer if the MachineFunction includes

MS-style inline assembly.

This is a follow-on to r175334.  Forcing a FP to be emitted doesn't ensure it
will be used.  Therefore, force the base pointer as well.  We now treat MS
inline assembly in the same way we treat functions with dynamic stack
realignment and VLAs.  This guarantees the BP will be used to reference 
parameters and locals.
rdar://13218191

llvm-svn: 175576

2 files changed, 6 insertions, 4 deletions

diff --git a/llvm/lib/Target/X86/X86RegisterInfo.cpp b/llvm/lib/Target/X86/X86RegisterInfo.cpp
index 401eefb16af..fbe6331e845 100644
--- a/llvm/lib/Target/X86/X86RegisterInfo.cpp
+++ b/llvm/lib/Target/X86/X86RegisterInfo.cpp
@@ -389,8 +389,10 @@ bool X86RegisterInfo::hasBasePointer(const MachineFunction &MF) const {
      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.
-   if (needsStackRealignment(MF) && MFI->hasVarSizedObjects())
+   // reference off of the stack pointer, so we reserve a base pointer.  This
+   // is also true if the function contain MS-style inline assembly.
+   if ((needsStackRealignment(MF) && MFI->hasVarSizedObjects()) ||
+       MF.hasMSInlineAsm())
      return true;
 
    return false;
diff --git a/llvm/test/CodeGen/X86/ms-inline-asm.ll b/llvm/test/CodeGen/X86/ms-inline-asm.ll
index eca174610da..5048a93ad30 100644
--- a/llvm/test/CodeGen/X86/ms-inline-asm.ll
+++ b/llvm/test/CodeGen/X86/ms-inline-asm.ll
@@ -103,8 +103,8 @@ entry:
 ; CHECK: {{## InlineAsm End|#NO_APP}}
 ; CHECK: {{## InlineAsm Start|#APP}}
 ; CHECK: .intel_syntax
-; CHECK: mov dword ptr [ebp - 8], edi
+; CHECK: mov dword ptr [esi], edi
 ; CHECK: .att_syntax
 ; CHECK: {{## InlineAsm End|#NO_APP}}
-; CHECK: movl -8(%ebp), %eax
+; CHECK: movl (%esi), %eax
 }