llvm-6502/test/Transforms/SimplifyCFG/switch_thread.ll
Chris Lattner d802347a2e new testcase for a simple optimization that simplifycfg is about to do.
All CFG edges to DEAD should be eliminated.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@20299 91177308-0d34-0410-b5e6-96231b3b80d8
2005-02-24 06:15:27 +00:00

79 lines
1.6 KiB
LLVM

; RUN: llvm-as < %s | opt -simplifycfg | llvm-dis | not grep 'call void %DEAD'
; Test that we can thread a simple known condition through switch statements.
declare void %foo1()
declare void %foo2()
declare void %DEAD()
void %test1(uint %V) {
switch uint %V, label %A [
uint 4, label %T
uint 17, label %Done
uint 1234, label %A
]
T: ;; V == 4 if we get here.
call void %foo1()
;; This switch is always statically determined.
switch uint %V, label %A2 [
uint 4, label %B
uint 17, label %C
uint 42, label %C
]
A2:
call void %DEAD()
call void %DEAD()
%cond2 = seteq uint %V, 4 ;; always false
br bool %cond2, label %Done, label %C
A:
call void %foo1()
%cond = setne uint %V, 4 ;; always true
br bool %cond, label %Done, label %C
Done:
ret void
B:
call void %foo2()
%cond3 = seteq uint %V, 4 ;; always true
br bool %cond3, label %Done, label %C
C:
call void %DEAD()
ret void
}
void %test2(uint %V) {
switch uint %V, label %A [
uint 4, label %T
uint 17, label %D
uint 1234, label %E
]
A: ;; V != 4, 17, 1234 here.
call void %foo1()
;; This switch is always statically determined.
switch uint %V, label %E [
uint 4, label %C
uint 17, label %C
uint 42, label %D
]
C:
call void %DEAD() ;; unreacahble.
ret void
T:
call void %foo1()
call void %foo1()
ret void
D:
call void %foo1()
ret void
E:
ret void
}