[llvm-commits] [llvm] r71520 - in /llvm/trunk/lib/Target/X86: X86CodeEmitter.cpp X86InstrInfo.cpp

[Evan Cheng]

Author: evancheng
Date: Mon May 11 19:07:35 2009
New Revision: 71520

URL: http://llvm.org/viewvc/llvm-project?rev=71520&view=rev
Log:
Avoid unneeded SIB byte encoding. Patch by Zoltan Varga.

Modified:
    llvm/trunk/lib/Target/X86/X86CodeEmitter.cpp
    llvm/trunk/lib/Target/X86/X86InstrInfo.cpp

Modified: llvm/trunk/lib/Target/X86/X86CodeEmitter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86CodeEmitter.cpp?rev=71520&r1=71519&r2=71520&view=diff

==============================================================================
--- llvm/trunk/lib/Target/X86/X86CodeEmitter.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86CodeEmitter.cpp Mon May 11 19:07:35 2009
@@ -338,7 +338,8 @@
   unsigned BaseReg = Base.getReg();
 
   // Is a SIB byte needed?
-  if ((!Is64BitMode || DispForReloc) && IndexReg.getReg() == 0 &&
+  if ((!Is64BitMode || DispForReloc || BaseReg != 0) &&
+      IndexReg.getReg() == 0 &&
       (BaseReg == 0 || getX86RegNum(BaseReg) != N86::ESP)) {
     if (BaseReg == 0) {  // Just a displacement?
       // Emit special case [disp32] encoding

Modified: llvm/trunk/lib/Target/X86/X86InstrInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86InstrInfo.cpp?rev=71520&r1=71519&r2=71520&view=diff

==============================================================================
--- llvm/trunk/lib/Target/X86/X86InstrInfo.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86InstrInfo.cpp Mon May 11 19:07:35 2009
@@ -2811,7 +2811,8 @@
   unsigned BaseReg = Base.getReg();
 
   // Is a SIB byte needed?
-  if ((!Is64BitMode || DispForReloc) && IndexReg.getReg() == 0 &&
+  if ((!Is64BitMode || DispForReloc || BaseReg != 0) &&
+      IndexReg.getReg() == 0 &&
       (BaseReg == 0 || X86RegisterInfo::getX86RegNum(BaseReg) != N86::ESP)) {      
     if (BaseReg == 0) {  // Just a displacement?
       // Emit special case [disp32] encoding