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llvm-6502/test/Transforms/JumpThreading/basic.ll
Chris Lattner 2249a0b1bd Teach jump threading to duplicate small blocks when the branch 
condition is a xor with a phi node.  This eliminates nonsense
like this from 176.gcc in several places:

 LBB166_84:
        testl   %eax, %eax
-       setne   %al
-       xorb    %cl, %al
-       notb    %al
-       testb   $1, %al
-       je      LBB166_85
+       je      LBB166_69
+       jmp     LBB166_85

This is rdar://7391699



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93221 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-12 02:07:17 +00:00

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; RUN: opt %s -jump-threading -S -enable-jump-threading-lvi | FileCheck %s
declare i32 @f1()
declare i32 @f2()
declare void @f3()
define i32 @test1(i1 %cond) {
; CHECK: @test1
br i1 %cond, label %T1, label %F1
T1:
%v1 = call i32 @f1()
br label %Merge
F1:
%v2 = call i32 @f2()
br label %Merge
Merge:
%A = phi i1 [true, %T1], [false, %F1]
%B = phi i32 [%v1, %T1], [%v2, %F1]
br i1 %A, label %T2, label %F2
T2:
; CHECK: T2:
; CHECK: ret i32 %v1
call void @f3()
ret i32 %B
F2:
; CHECK: F2:
; CHECK: ret i32 %v2
ret i32 %B
}
;; cond is known false on Entry -> F1 edge!
define i32 @test2(i1 %cond) {
; CHECK: @test2
Entry:
br i1 %cond, label %T1, label %F1
T1:
; CHECK: %v1 = call i32 @f1()
; CHECK: ret i32 47
%v1 = call i32 @f1()
br label %Merge
F1:
br i1 %cond, label %Merge, label %F2
Merge:
%B = phi i32 [47, %T1], [192, %F1]
ret i32 %B
F2:
call void @f3()
ret i32 12
}
; Undef handling.
define i32 @test3(i1 %cond) {
; CHECK: @test3
; CHECK-NEXT: T1:
; CHECK-NEXT: ret i32 42
br i1 undef, label %T1, label %F1
T1:
ret i32 42
F1:
ret i32 17
}
define i32 @test4(i1 %cond, i1 %cond2) {
; CHECK: @test4
br i1 %cond, label %T1, label %F1
T1:
; CHECK: %v1 = call i32 @f1()
; CHECK-NEXT: br label %T
%v1 = call i32 @f1()
br label %Merge
F1:
%v2 = call i32 @f2()
; CHECK: %v2 = call i32 @f2()
; CHECK-NEXT: br i1 %cond2,
br label %Merge
Merge:
%A = phi i1 [undef, %T1], [%cond2, %F1]
%B = phi i32 [%v1, %T1], [%v2, %F1]
br i1 %A, label %T2, label %F2
T2:
call void @f3()
ret i32 %B
F2:
ret i32 %B
}
;; This tests that the branch in 'merge' can be cloned up into T1.
define i32 @test5(i1 %cond, i1 %cond2) {
; CHECK: @test5
br i1 %cond, label %T1, label %F1
T1:
; CHECK: T1:
; CHECK-NEXT: %v1 = call i32 @f1()
; CHECK-NEXT: %cond3 = icmp eq i32 %v1, 412
; CHECK-NEXT: br i1 %cond3, label %T2, label %F2
%v1 = call i32 @f1()
%cond3 = icmp eq i32 %v1, 412
br label %Merge
F1:
%v2 = call i32 @f2()
br label %Merge
Merge:
%A = phi i1 [%cond3, %T1], [%cond2, %F1]
%B = phi i32 [%v1, %T1], [%v2, %F1]
br i1 %A, label %T2, label %F2
T2:
call void @f3()
ret i32 %B
F2:
ret i32 %B
}
;; Lexically duplicated conditionals should be threaded.
define i32 @test6(i32 %A) {
; CHECK: @test6
%tmp455 = icmp eq i32 %A, 42
br i1 %tmp455, label %BB1, label %BB2
BB2:
; CHECK: call i32 @f1()
; CHECK-NEXT: call void @f3()
; CHECK-NEXT: ret i32 4
call i32 @f1()
br label %BB1
BB1:
%tmp459 = icmp eq i32 %A, 42
br i1 %tmp459, label %BB3, label %BB4
BB3:
call i32 @f2()
ret i32 3
BB4:
call void @f3()
ret i32 4
}
;; This tests that the branch in 'merge' can be cloned up into T1.
;; rdar://7367025
define i32 @test7(i1 %cond, i1 %cond2) {
Entry:
; CHECK: @test7
%v1 = call i32 @f1()
br i1 %cond, label %Merge, label %F1
F1:
%v2 = call i32 @f2()
br label %Merge
Merge:
%B = phi i32 [%v1, %Entry], [%v2, %F1]
%M = icmp ne i32 %B, %v1
%N = icmp eq i32 %B, 47
%O = and i1 %M, %N
br i1 %O, label %T2, label %F2
; CHECK: Merge:
; CHECK-NOT: phi
; CHECK-NEXT: %v2 = call i32 @f2()
T2:
call void @f3()
ret i32 %B
F2:
ret i32 %B
; CHECK: F2:
; CHECK-NEXT: phi i32
}
declare i1 @test8a()
define i32 @test8b(i1 %cond, i1 %cond2) {
; CHECK: @test8b
T0:
%A = call i1 @test8a()
br i1 %A, label %T1, label %F1
; CHECK: T0:
; CHECK-NEXT: call
; CHECK-NEXT: br i1 %A, label %T1, label %Y
T1:
%B = call i1 @test8a()
br i1 %B, label %T2, label %F1
; CHECK: T1:
; CHECK-NEXT: call
; CHECK-NEXT: br i1 %B, label %T2, label %Y
T2:
%C = call i1 @test8a()
br i1 %cond, label %T3, label %F1
; CHECK: T2:
; CHECK-NEXT: call
; CHECK-NEXT: br i1 %cond, label %T3, label %Y
T3:
ret i32 0
F1:
%D = phi i32 [0, %T0], [0, %T1], [1, %T2]
%E = icmp eq i32 %D, 1
%F = and i1 %E, %cond
br i1 %F, label %X, label %Y
X:
call i1 @test8a()
ret i32 1
Y:
ret i32 2
}
;;; Verify that we can handle constraint propagation through "xor x, 1".
define i32 @test9(i1 %cond, i1 %cond2) {
Entry:
; CHECK: @test9
%v1 = call i32 @f1()
br i1 %cond, label %Merge, label %F1
; CHECK: Entry:
; CHECK-NEXT: %v1 = call i32 @f1()
; CHECK-NEXT: br i1 %cond, label %F2, label %Merge
F1:
%v2 = call i32 @f2()
br label %Merge
Merge:
%B = phi i32 [%v1, %Entry], [%v2, %F1]
%M = icmp eq i32 %B, %v1
%M1 = xor i1 %M, 1
%N = icmp eq i32 %B, 47
%O = and i1 %M1, %N
br i1 %O, label %T2, label %F2
; CHECK: Merge:
; CHECK-NOT: phi
; CHECK-NEXT: %v2 = call i32 @f2()
T2:
%Q = zext i1 %M to i32
ret i32 %Q
F2:
ret i32 %B
; CHECK: F2:
; CHECK-NEXT: phi i32
}
; CHECK: @test10
declare i32 @test10f1()
declare i32 @test10f2()
declare void @test10f3()
;; Non-local condition threading.
define i32 @test10g(i1 %cond) {
; CHECK: @test10g
; CHECK-NEXT: br i1 %cond, label %T2, label %F2
br i1 %cond, label %T1, label %F1
T1:
%v1 = call i32 @test10f1()
br label %Merge
; CHECK: %v1 = call i32 @test10f1()
; CHECK-NEXT: call void @f3()
; CHECK-NEXT: ret i32 %v1
F1:
%v2 = call i32 @test10f2()
br label %Merge
Merge:
%B = phi i32 [%v1, %T1], [%v2, %F1]
br i1 %cond, label %T2, label %F2
T2:
call void @f3()
ret i32 %B
F2:
ret i32 %B
}
; Impossible conditional constraints should get threaded. BB3 is dead here.
define i32 @test11(i32 %A) {
; CHECK: @test11
; CHECK-NEXT: icmp
; CHECK-NEXT: br i1 %tmp455, label %BB4, label %BB2
%tmp455 = icmp eq i32 %A, 42
br i1 %tmp455, label %BB1, label %BB2
BB2:
; CHECK: call i32 @f1()
; CHECK-NEXT: ret i32 %C
%C = call i32 @f1()
ret i32 %C
BB1:
%tmp459 = icmp eq i32 %A, 43
br i1 %tmp459, label %BB3, label %BB4
BB3:
call i32 @f2()
ret i32 3
BB4:
call void @f3()
ret i32 4
}
;; Correlated value through boolean expression. GCC PR18046.
define void @test12(i32 %A) {
; CHECK: @test12
entry:
%cond = icmp eq i32 %A, 0
br i1 %cond, label %bb, label %bb1
; Should branch to the return block instead of through BB1.
; CHECK: entry:
; CHECK-NEXT: %cond = icmp eq i32 %A, 0
; CHECK-NEXT: br i1 %cond, label %bb1, label %return
bb:
%B = call i32 @test10f2()
br label %bb1
bb1:
%C = phi i32 [ %A, %entry ], [ %B, %bb ]
%cond4 = icmp eq i32 %C, 0
br i1 %cond4, label %bb2, label %return
; CHECK: bb1:
; CHECK-NEXT: %B = call i32 @test10f2()
; CHECK-NEXT: %cond4 = icmp eq i32 %B, 0
; CHECK-NEXT: br i1 %cond4, label %bb2, label %return
bb2:
%D = call i32 @test10f2()
ret void
return:
ret void
}
;; Duplicate condition to avoid xor of cond.
;; rdar://7391699
define i32 @test13(i1 %cond, i1 %cond2) {
Entry:
; CHECK: @test13
%v1 = call i32 @f1()
br i1 %cond, label %Merge, label %F1
F1:
br label %Merge
Merge:
%B = phi i1 [true, %Entry], [%cond2, %F1]
%C = phi i32 [192, %Entry], [%v1, %F1]
%M = icmp eq i32 %C, 192
%N = xor i1 %B, %M
br i1 %N, label %T2, label %F2
T2:
ret i32 123
F2:
ret i32 %v1
;; FIXME: CONSTANT FOLD on clone and when phi gets eliminated.
; CHECK: Entry.Merge_crit_edge:
; CHECK-NEXT: %M1 = icmp eq i32 192, 192
; CHECK-NEXT: %N2 = xor i1 true, %M1
; CHECK-NEXT: br i1 %N2, label %T2, label %F2
; CHECK: Merge:
; CHECK-NEXT: %M = icmp eq i32 %v1, 192
; CHECK-NEXT: %N = xor i1 %cond2, %M
; CHECK-NEXT: br i1 %N, label %T2, label %F2
}
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