[llvm] r201377 - [X86] Don't mark movabsq as cheap-as-move - it isn't that cheap.

[Juergen Ributzka]

Author: ributzka
Date: Thu Feb 13 18:51:13 2014
New Revision: 201377

URL: http://llvm.org/viewvc/llvm-project?rev=201377&view=rev
Log:
[X86] Don't mark movabsq as cheap-as-move - it isn't that cheap.

A simple register copy on X86 is just 3 bytes, whereas movabsq is a 10 byte
instruction. Marking movabsq as not beeing cheap will allow LICM to move it
out of the loop and it also prevents unnecessary rematerializations if the
value is needed in more than one register.

Modified:
    llvm/trunk/lib/Target/X86/X86InstrInfo.td

Modified: llvm/trunk/lib/Target/X86/X86InstrInfo.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86InstrInfo.td?rev=201377&r1=201376&r2=201377&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86InstrInfo.td (original)
+++ llvm/trunk/lib/Target/X86/X86InstrInfo.td Thu Feb 13 18:51:13 2014
@@ -1203,13 +1203,15 @@ def MOV16ri : Ii16<0xB8, AddRegFrm, (out
 def MOV32ri : Ii32<0xB8, AddRegFrm, (outs GR32:$dst), (ins i32imm:$src),
                    "mov{l}\t{$src, $dst|$dst, $src}",
                    [(set GR32:$dst, imm:$src)], IIC_MOV>, OpSize32;
-def MOV64ri : RIi64<0xB8, AddRegFrm, (outs GR64:$dst), (ins i64imm:$src),
-                    "movabs{q}\t{$src, $dst|$dst, $src}",
-                    [(set GR64:$dst, imm:$src)], IIC_MOV>;
 def MOV64ri32 : RIi32S<0xC7, MRM0r, (outs GR64:$dst), (ins i64i32imm:$src),
                        "mov{q}\t{$src, $dst|$dst, $src}",
                        [(set GR64:$dst, i64immSExt32:$src)], IIC_MOV>;
 }
+let isReMaterializable = 1 in {
+def MOV64ri : RIi64<0xB8, AddRegFrm, (outs GR64:$dst), (ins i64imm:$src),
+                    "movabs{q}\t{$src, $dst|$dst, $src}",
+                    [(set GR64:$dst, imm:$src)], IIC_MOV>;
+}
 } // SchedRW
 
 let SchedRW = [WriteStore] in {