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; This test makes sure that these instructions are properly eliminated.
;
; RUN: opt < %s -instcombine -S | FileCheck %s
define i32 @test1(i32 %A, i1 %b) {
BB0:
br i1 %b, label %BB1, label %BB2
BB1:
; Combine away one argument PHI nodes
%B = phi i32 [ %A, %BB0 ]
ret i32 %B
BB2:
ret i32 %A
; CHECK: @test1
; CHECK: BB1:
; CHECK-NEXT: ret i32 %A
}
define i32 @test2(i32 %A, i1 %b) {
BB0:
br i1 %b, label %BB1, label %BB2
BB1:
br label %BB2
BB2:
; Combine away PHI nodes with same values
%B = phi i32 [ %A, %BB0 ], [ %A, %BB1 ]
ret i32 %B
; CHECK: @test2
; CHECK: BB2:
; CHECK-NEXT: ret i32 %A
}
define i32 @test3(i32 %A, i1 %b) {
BB0:
br label %Loop
Loop:
; PHI has same value always.
%B = phi i32 [ %A, %BB0 ], [ %B, %Loop ]
br i1 %b, label %Loop, label %Exit
Exit:
ret i32 %B
; CHECK: @test3
; CHECK: Exit:
; CHECK-NEXT: ret i32 %A
}
define i32 @test4(i1 %b) {
BB0:
; Loop is unreachable
ret i32 7
Loop: ; preds = %L2, %Loop
; PHI has same value always.
%B = phi i32 [ %B, %L2 ], [ %B, %Loop ]
br i1 %b, label %L2, label %Loop
L2: ; preds = %Loop
br label %Loop
; CHECK: @test4
; CHECK: Loop:
; CHECK-NEXT: br i1 %b
}
define i32 @test5(i32 %A, i1 %b) {
BB0:
br label %Loop
Loop: ; preds = %Loop, %BB0
; PHI has same value always.
%B = phi i32 [ %A, %BB0 ], [ undef, %Loop ]
br i1 %b, label %Loop, label %Exit
Exit: ; preds = %Loop
ret i32 %B
; CHECK: @test5
; CHECK: Loop:
; CHECK-NEXT: br i1 %b
; CHECK: Exit:
; CHECK-NEXT: ret i32 %A
}
define i32 @test6(i16 %A, i1 %b) {
BB0:
%X = zext i16 %A to i32
br i1 %b, label %BB1, label %BB2
BB1:
%Y = zext i16 %A to i32
br label %BB2
BB2:
;; Suck casts into phi
%B = phi i32 [ %X, %BB0 ], [ %Y, %BB1 ]
ret i32 %B
; CHECK: @test6
; CHECK: BB2:
; CHECK: zext i16 %A to i32
; CHECK-NEXT: ret i32
}
define i32 @test7(i32 %A, i1 %b) {
BB0:
br label %Loop
Loop: ; preds = %Loop, %BB0
; PHI is dead.
%B = phi i32 [ %A, %BB0 ], [ %C, %Loop ]
%C = add i32 %B, 123
br i1 %b, label %Loop, label %Exit
Exit: ; preds = %Loop
ret i32 0
; CHECK: @test7
; CHECK: Loop:
; CHECK-NEXT: br i1 %b
}
define i32* @test8({ i32, i32 } *%A, i1 %b) {
BB0:
%X = getelementptr { i32, i32 } *%A, i32 0, i32 1
br i1 %b, label %BB1, label %BB2
BB1:
%Y = getelementptr { i32, i32 } *%A, i32 0, i32 1
br label %BB2
BB2:
;; Suck GEPs into phi
%B = phi i32* [ %X, %BB0 ], [ %Y, %BB1 ]
ret i32* %B
; CHECK: @test8
; CHECK-NOT: phi
; CHECK: BB2:
; CHECK-NEXT: %B = getelementptr
; CHECK-NEXT: ret i32* %B
}
define i32 @test9(i32* %A, i32* %B) {
entry:
%c = icmp eq i32* %A, null
br i1 %c, label %bb1, label %bb
bb:
%C = load i32* %B, align 1
br label %bb2
bb1:
%D = load i32* %A, align 1
br label %bb2
bb2:
%E = phi i32 [ %C, %bb ], [ %D, %bb1 ]
ret i32 %E
; CHECK: bb2:
; CHECK-NEXT: phi i32* [ %B, %bb ], [ %A, %bb1 ]
; CHECK-NEXT: %E = load i32* %{{[^,]*}}, align 1
; CHECK-NEXT: ret i32 %E
}
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