Disable 2->3 address promotion of add and inc instructions to LEA's. In

addition to being three address, LEA's don't set the flags.

This fixes 186.crafty.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19251 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/X86InstrInfo.cpp b/lib/Target/X86/X86InstrInfo.cpp
index d588afe28af5dd445c766b3f4fd2a23e1b4815ab..a13498e3ae4b9561dedc1629225345fd3febd138 100644 (file)
--- a/lib/Target/X86/X86InstrInfo.cpp
+++ b/lib/Target/X86/X86InstrInfo.cpp
@@ -55,6 +55,11 @@ MachineInstr *X86InstrInfo::convertToThreeAddress(MachineInstr *MI) const {
   unsigned Dest = MI->getOperand(0).getReg();
   unsigned Src = MI->getOperand(1).getReg();
 
+  // FIXME: None of these instructions are promotable to LEAs without 
+  // additional information.  In particular, LEA doesn't set the flags that 
+  // add and inc do.  :(
+  return 0;
+
   // FIXME: 16-bit LEA's are really slow on Athlons, but not bad on P4's.  When
   // we have subtarget support, enable the 16-bit LEA generation here.
   bool DisableLEA16 = true;