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llvm-project/llvm/test/Transforms/JumpThreading/basic.ll

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simplify some run lines, convert a test to filecheck. llvm-svn: 83750
2009-10-11 11:54:21 +08:00
; RUN: opt < %s -jump-threading -S | FileCheck %s
add a basic testcase. llvm-svn: 50093
2008-04-22 14:35:14 +08:00
declare i32 @f1()
declare i32 @f2()
declare void @f3()
merge two tests. llvm-svn: 83751
2009-10-11 11:55:30 +08:00
define i32 @test1(i1 %cond) {
; CHECK: @test1
add a basic testcase. llvm-svn: 50093
2008-04-22 14:35:14 +08:00
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:
simplify some run lines, convert a test to filecheck. llvm-svn: 83750
2009-10-11 11:54:21 +08:00
; CHECK: T2:
; CHECK: ret i32 %v1
add a basic testcase. llvm-svn: 50093
2008-04-22 14:35:14 +08:00
call void @f3()
ret i32 %B
F2:
simplify some run lines, convert a test to filecheck. llvm-svn: 83750
2009-10-11 11:54:21 +08:00
; CHECK: F2:
; CHECK: ret i32 %v2
add a basic testcase. llvm-svn: 50093
2008-04-22 14:35:14 +08:00
ret i32 %B
}
Teach jump threading some more simple tricks: 1) have it fold "br undef", which does occur with surprising frequency as jump threading iterates. 2) teach j-t to delete dead blocks. This removes the successor edges, reducing the in-edges of other blocks, allowing recursive simplification. 3) Fold things like: br COND, BBX, BBY BBX: br COND, BBZ, BBW which also happens because jump threading iterates. llvm-svn: 60470
2008-12-03 15:48:08 +08:00
;; cond is known false on Entry -> F1 edge!
define i32 @test2(i1 %cond) {
merge two tests. llvm-svn: 83751
2009-10-11 11:55:30 +08:00
; CHECK: @test2
Teach jump threading some more simple tricks: 1) have it fold "br undef", which does occur with surprising frequency as jump threading iterates. 2) teach j-t to delete dead blocks. This removes the successor edges, reducing the in-edges of other blocks, allowing recursive simplification. 3) Fold things like: br COND, BBX, BBY BBX: br COND, BBZ, BBW which also happens because jump threading iterates. llvm-svn: 60470
2008-12-03 15:48:08 +08:00
Entry:
br i1 %cond, label %T1, label %F1
T1:
simplify some run lines, convert a test to filecheck. llvm-svn: 83750
2009-10-11 11:54:21 +08:00
; CHECK: %v1 = call i32 @f1()
; CHECK: ret i32 47
Teach jump threading some more simple tricks: 1) have it fold "br undef", which does occur with surprising frequency as jump threading iterates. 2) teach j-t to delete dead blocks. This removes the successor edges, reducing the in-edges of other blocks, allowing recursive simplification. 3) Fold things like: br COND, BBX, BBY BBX: br COND, BBZ, BBW which also happens because jump threading iterates. llvm-svn: 60470
2008-12-03 15:48:08 +08:00
%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
}
merge two tests. llvm-svn: 83751
2009-10-11 11:55:30 +08:00
; 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
}
make jump threading on a phi with undef inputs happen. llvm-svn: 83754
2009-10-11 12:18:15 +08:00
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
}
implement a transformation in jump threading that is currently done by condprop, but do it in a much more general form. The basic idea is that we can do a limited form of tail duplication in the case when we have a branch on a phi. Moving the branch up in to the predecessor block makes instruction selection much easier and encourages chained jump threadings. llvm-svn: 83759
2009-10-11 15:24:57 +08:00
;; 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
}
when folding duplicate conditions, delete the now-probably-dead instruction tree feeding it. llvm-svn: 83778
2009-10-12 02:39:58 +08:00
;; 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
}