From 5aee0b97aa46cb25ccfe157a3a5612d155519b28 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Sun, 2 Jan 2005 04:18:17 +0000 Subject: [PATCH] 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 --- lib/Target/X86/X86InstrInfo.cpp | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/lib/Target/X86/X86InstrInfo.cpp b/lib/Target/X86/X86InstrInfo.cpp index d588afe28af..a13498e3ae4 100644 --- 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; -- 2.34.1