llvm/test/Transforms/SCCP/2002-05-02-EdgeFailure.ll

29 lines
872 B
LLVM
Raw Normal View History

; 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: if as < %s | opt -sccp | dis | grep loop
; RUN: then exit 1
; RUN: else exit 0
; RUN: fi
int *"test"()
begin
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
end