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Addd (shl x, 1) ==> (shl x, x) peepholes. 

llvm-svn: 25123
This commit is contained in:
Evan Cheng 2006-01-06 02:31:59 +00:00
parent 46634d21e3
commit 53dd0ac226
1 changed files with 10 additions and 1 deletions
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11
llvm/lib/Target/X86/X86InstrInfo.td
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@ -1343,7 +1343,6 @@ let isTwoAddress = 0 in {
}
// Shift instructions
// FIXME: provide shorter instructions when imm8 == 1
def SHL8rCL : I<0xD2, MRM4r, (ops R8 :$dst, R8 :$src),
"shl{b} {%cl, $dst|$dst, %CL}",
[(set R8:$dst, (shl R8:$src, CL))]>, Imp<[CL],[]>;
@ -2756,3 +2755,13 @@ def FLDCW16m : I<0xD9, MRM5m, // X87 control world = [mem16]
//===----------------------------------------------------------------------===//
def RDTSC : I<0x31, RawFrm, (ops), "rdtsc", []>, TB, Imp<[],[EAX,EDX]>;
//===----------------------------------------------------------------------===//
// Some peepholes
//===----------------------------------------------------------------------===//
// (shl x, 1) ==> (add x, x)
def : Pat<(shl R8 :$src1, (i8 1)), (ADD8rr R8 :$src1, R8 :$src1)>;
def : Pat<(shl R16:$src1, (i8 1)), (ADD16rr R16:$src1, R16:$src1)>;
def : Pat<(shl R32:$src1, (i8 1)), (ADD32rr R32:$src1, R32:$src1)>;