commit 92569cebd5be392964f9a6e967becfa614f18f67
author Evan Cheng <evan.cheng@apple.com> Tue May 12 00:07:35 2009 +0000
committer Evan Cheng <evan.cheng@apple.com> Tue May 12 00:07:35 2009 +0000
tree 71eb67519d2af9ef5970bcab85289655236472d8
parent dea0ec265e17840423c49ee1608bc8d9d3205037

Avoid unneeded SIB byte encoding. Patch by Zoltan Varga.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71520 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/X86/X86CodeEmitter.cpp

diff --git a/lib/Target/X86/X86CodeEmitter.cpp b/lib/Target/X86/X86CodeEmitter.cpp
index c21eacc..63bf18d 100644
--- a/lib/Target/X86/X86CodeEmitter.cpp
+++ b/lib/Target/X86/X86CodeEmitter.cpp
@@ -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

lib/Target/X86/X86InstrInfo.cpp

diff --git a/lib/Target/X86/X86InstrInfo.cpp b/lib/Target/X86/X86InstrInfo.cpp
index 369c4c6..85756a1 100644
--- a/lib/Target/X86/X86InstrInfo.cpp
+++ b/lib/Target/X86/X86InstrInfo.cpp
@@ -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