llvm-project/llvm/test/Transforms/SCCP/sccptest.ll

35 lines
731 B
LLVM

; This is the test case taken from appel's book that illustrates a hard case
; that SCCP gets right. BB3 should be completely eliminated.
;
; RUN: llvm-upgrade < %s | llvm-as | opt -sccp -constprop -dce -cfgsimplify | llvm-dis | not grep BB3
int %testfunction(int %i0, int %j0) {
BB1:
br label %BB2
BB2:
%j2 = phi int [%j4, %BB7], [1, %BB1]
%k2 = phi int [%k4, %BB7], [0, %BB1]
%kcond = setlt int %k2, 100
br bool %kcond, label %BB3, label %BB4
BB3:
%jcond = setlt int %j2, 20
br bool %jcond, label %BB5, label %BB6
BB4:
ret int %j2
BB5:
%k3 = add int %k2, 1
br label %BB7
BB6:
%k5 = add int %k2, 1
br label %BB7
BB7:
%j4 = phi int [1, %BB5], [%k2, %BB6]
%k4 = phi int [%k3, %BB5], [%k5, %BB6]
br label %BB2
}