Remove README entry which no longer compiles to something sane.

llvm-svn: 105376

llvm/lib/Target/X86/README-SSE.txt

@@ -36,62 +36,6 @@ The pattern isel got this one right.
 
 //===---------------------------------------------------------------------===//
 
-SSE doesn't have [mem] op= reg instructions.  If we have an SSE instruction
-like this:
-
-  X += y
-
-and the register allocator decides to spill X, it is cheaper to emit this as:
-
-Y += [xslot]
-store Y -> [xslot]
-
-than as:
-
-tmp = [xslot]
-tmp += y
-store tmp -> [xslot]
-
-..and this uses one fewer register (so this should be done at load folding
-time, not at spiller time).  *Note* however that this can only be done
-if Y is dead.  Here's a testcase:
-
-@.str_3 = external global [15 x i8]
-declare void @printf(i32, ...)
-define void @main() {
-build_tree.exit:
-	br label %no_exit.i7
-
-no_exit.i7:		; preds = %no_exit.i7, %build_tree.exit
-	%tmp.0.1.0.i9 = phi double [ 0.000000e+00, %build_tree.exit ],
-                                   [ %tmp.34.i18, %no_exit.i7 ]
-	%tmp.0.0.0.i10 = phi double [ 0.000000e+00, %build_tree.exit ],
-                                    [ %tmp.28.i16, %no_exit.i7 ]
-	%tmp.28.i16 = fadd double %tmp.0.0.0.i10, 0.000000e+00
-	%tmp.34.i18 = fadd double %tmp.0.1.0.i9, 0.000000e+00
-	br i1 false, label %Compute_Tree.exit23, label %no_exit.i7
-
-Compute_Tree.exit23:		; preds = %no_exit.i7
-	tail call void (i32, ...)* @printf( i32 0 )
-	store double %tmp.34.i18, double* null
-	ret void
-}
-
-We currently emit:
-
-.BBmain_1:
-        xorpd %XMM1, %XMM1
-        addsd %XMM0, %XMM1
-***     movsd %XMM2, QWORD PTR [%ESP + 8]
-***     addsd %XMM2, %XMM1
-***     movsd QWORD PTR [%ESP + 8], %XMM2
-        jmp .BBmain_1   # no_exit.i7
-
-This is a bugpoint reduced testcase, which is why the testcase doesn't make
-much sense (e.g. its an infinite loop). :)
-
-//===---------------------------------------------------------------------===//
-
 SSE should implement 'select_cc' using 'emulated conditional moves' that use
 pcmp/pand/pandn/por to do a selection instead of a conditional branch: