llvm-6502/test/Transforms/SCCP/2002-05-02-EdgeFailure.ll
2003-06-28 23:23:34 +00:00

24 lines
817 B
LLVM

; edgefailure - This function illustrates how SCCP is not doing it's job. This
; function should be optimized almost completely away: the loop should be
; analyzed to detect that the body executes exactly once, and thus the branch
; can be eliminated and code becomes trivially dead. This is distilled from a
; real benchmark (mst from Olden benchmark, MakeGraph function). When SCCP is
; fixed, this should be eliminated by a single SCCP application.
;
; RUN: as < %s | opt -sccp | dis | not grep loop
int* %test() {
bb1:
%A = malloc int
br label %bb2
bb2:
%i = phi int [ %i2, %bb2 ], [ 0, %bb1 ] ;; Always 0
%i2 = add int %i, 1 ;; Always 1
store int %i, int *%A
%loop = setle int %i2, 0 ;; Always false
br bool %loop, label %bb2, label %bb3
bb3:
ret int * %A
}