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llvm-mirror/test/Transforms/InstCombine/phi.ll
Duncan Sands 825c7d7f79 In which I discover the existence of loops. Threading an operation
over a phi node by applying it to each operand may be wrong if the
operation and the phi node are mutually interdependent (the testcase
has a simple example of this).  So only do this transform if it would
be correct to perform the operation in each predecessor of the block
containing the phi, i.e. if the other operands all dominate the phi.
This should fix the FFMPEG snow.c regression reported by İsmail Dönmez.

llvm-svn: 119347
2010-11-16 12:16:38 +00:00

506 lines
12 KiB
LLVM

; This test makes sure that these instructions are properly eliminated.
;
; RUN: opt < %s -instcombine -S | FileCheck %s
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128:n8:16:32:64"
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: @test9
; CHECK: bb2:
; CHECK-NEXT: phi i32* [ %B, %bb ], [ %A, %bb1 ]
; CHECK-NEXT: %E = load i32* %{{[^,]*}}, align 1
; CHECK-NEXT: ret i32 %E
}
define i32 @test10(i32* %A, i32* %B) {
entry:
%c = icmp eq i32* %A, null
br i1 %c, label %bb1, label %bb
bb:
%C = load i32* %B, align 16
br label %bb2
bb1:
%D = load i32* %A, align 32
br label %bb2
bb2:
%E = phi i32 [ %C, %bb ], [ %D, %bb1 ]
ret i32 %E
; CHECK: @test10
; CHECK: bb2:
; CHECK-NEXT: phi i32* [ %B, %bb ], [ %A, %bb1 ]
; CHECK-NEXT: %E = load i32* %{{[^,]*}}, align 16
; CHECK-NEXT: ret i32 %E
}
; PR1777
declare i1 @test11a()
define i1 @test11() {
entry:
%a = alloca i32
%i = ptrtoint i32* %a to i32
%b = call i1 @test11a()
br i1 %b, label %one, label %two
one:
%x = phi i32 [%i, %entry], [%y, %two]
%c = call i1 @test11a()
br i1 %c, label %two, label %end
two:
%y = phi i32 [%i, %entry], [%x, %one]
%d = call i1 @test11a()
br i1 %d, label %one, label %end
end:
%f = phi i32 [ %x, %one], [%y, %two]
; Change the %f to %i, and the optimizer suddenly becomes a lot smarter
; even though %f must equal %i at this point
%g = inttoptr i32 %f to i32*
store i32 10, i32* %g
%z = call i1 @test11a()
ret i1 %z
; CHECK: @test11
; CHECK-NOT: phi i32
; CHECK: ret i1 %z
}
define i64 @test12(i1 %cond, i8* %Ptr, i64 %Val) {
entry:
%tmp41 = ptrtoint i8* %Ptr to i64
%tmp42 = zext i64 %tmp41 to i128
br i1 %cond, label %end, label %two
two:
%tmp36 = zext i64 %Val to i128 ; <i128> [#uses=1]
%tmp37 = shl i128 %tmp36, 64 ; <i128> [#uses=1]
%ins39 = or i128 %tmp42, %tmp37 ; <i128> [#uses=1]
br label %end
end:
%tmp869.0 = phi i128 [ %tmp42, %entry ], [ %ins39, %two ]
%tmp32 = trunc i128 %tmp869.0 to i64 ; <i64> [#uses=1]
%tmp29 = lshr i128 %tmp869.0, 64 ; <i128> [#uses=1]
%tmp30 = trunc i128 %tmp29 to i64 ; <i64> [#uses=1]
%tmp2 = add i64 %tmp32, %tmp30
ret i64 %tmp2
; CHECK: @test12
; CHECK-NOT: zext
; CHECK: end:
; CHECK-NEXT: phi i64 [ 0, %entry ], [ %Val, %two ]
; CHECK-NOT: phi
; CHECK: ret i64
}
declare void @test13f(double, i32)
define void @test13(i1 %cond, i32 %V1, double %Vald) {
entry:
%tmp42 = zext i32 %V1 to i128
br i1 %cond, label %end, label %two
two:
%Val = bitcast double %Vald to i64
%tmp36 = zext i64 %Val to i128 ; <i128> [#uses=1]
%tmp37 = shl i128 %tmp36, 64 ; <i128> [#uses=1]
%ins39 = or i128 %tmp42, %tmp37 ; <i128> [#uses=1]
br label %end
end:
%tmp869.0 = phi i128 [ %tmp42, %entry ], [ %ins39, %two ]
%tmp32 = trunc i128 %tmp869.0 to i32
%tmp29 = lshr i128 %tmp869.0, 64 ; <i128> [#uses=1]
%tmp30 = trunc i128 %tmp29 to i64 ; <i64> [#uses=1]
%tmp31 = bitcast i64 %tmp30 to double
call void @test13f(double %tmp31, i32 %tmp32)
ret void
; CHECK: @test13
; CHECK-NOT: zext
; CHECK: end:
; CHECK-NEXT: phi double [ 0.000000e+00, %entry ], [ %Vald, %two ]
; CHECK-NEXT: call void @test13f(double {{[^,]*}}, i32 %V1)
; CHECK: ret void
}
define i640 @test14a(i320 %A, i320 %B, i1 %b1) {
BB0:
%a = zext i320 %A to i640
%b = zext i320 %B to i640
br label %Loop
Loop:
%C = phi i640 [ %a, %BB0 ], [ %b, %Loop ]
br i1 %b1, label %Loop, label %Exit
Exit: ; preds = %Loop
ret i640 %C
; CHECK: @test14a
; CHECK: Loop:
; CHECK-NEXT: phi i320
}
define i160 @test14b(i320 %A, i320 %B, i1 %b1) {
BB0:
%a = trunc i320 %A to i160
%b = trunc i320 %B to i160
br label %Loop
Loop:
%C = phi i160 [ %a, %BB0 ], [ %b, %Loop ]
br i1 %b1, label %Loop, label %Exit
Exit: ; preds = %Loop
ret i160 %C
; CHECK: @test14b
; CHECK: Loop:
; CHECK-NEXT: phi i160
}
declare i64 @test15a(i64)
define i64 @test15b(i64 %A, i1 %b) {
; CHECK: @test15b
entry:
%i0 = zext i64 %A to i128
%i1 = shl i128 %i0, 64
%i = or i128 %i1, %i0
br i1 %b, label %one, label %two
; CHECK: entry:
; CHECK-NEXT: br i1 %b
one:
%x = phi i128 [%i, %entry], [%y, %two]
%x1 = lshr i128 %x, 64
%x2 = trunc i128 %x1 to i64
%c = call i64 @test15a(i64 %x2)
%c1 = zext i64 %c to i128
br label %two
; CHECK: one:
; CHECK-NEXT: phi i64
; CHECK-NEXT: %c = call i64 @test15a
two:
%y = phi i128 [%i, %entry], [%c1, %one]
%y1 = lshr i128 %y, 64
%y2 = trunc i128 %y1 to i64
%d = call i64 @test15a(i64 %y2)
%d1 = trunc i64 %d to i1
br i1 %d1, label %one, label %end
; CHECK: two:
; CHECK-NEXT: phi i64
; CHECK-NEXT: phi i64
; CHECK-NEXT: %d = call i64 @test15a
end:
%g = trunc i128 %y to i64
ret i64 %g
; CHECK: end:
; CHECK-NEXT: ret i64
}
; PR6512 - Shouldn't merge loads from different addr spaces.
define i32 @test16(i32 addrspace(1)* %pointer1, i32 %flag, i32* %pointer2)
nounwind {
entry:
%retval = alloca i32, align 4 ; <i32*> [#uses=2]
%pointer1.addr = alloca i32 addrspace(1)*, align 4 ; <i32 addrspace(1)**>
%flag.addr = alloca i32, align 4 ; <i32*> [#uses=2]
%pointer2.addr = alloca i32*, align 4 ; <i32**> [#uses=2]
%res = alloca i32, align 4 ; <i32*> [#uses=4]
store i32 addrspace(1)* %pointer1, i32 addrspace(1)** %pointer1.addr
store i32 %flag, i32* %flag.addr
store i32* %pointer2, i32** %pointer2.addr
store i32 10, i32* %res
%tmp = load i32* %flag.addr ; <i32> [#uses=1]
%tobool = icmp ne i32 %tmp, 0 ; <i1> [#uses=1]
br i1 %tobool, label %if.then, label %if.else
return: ; preds = %if.end
%tmp7 = load i32* %retval ; <i32> [#uses=1]
ret i32 %tmp7
if.end: ; preds = %if.else, %if.then
%tmp6 = load i32* %res ; <i32> [#uses=1]
store i32 %tmp6, i32* %retval
br label %return
if.then: ; preds = %entry
%tmp1 = load i32 addrspace(1)** %pointer1.addr ; <i32 addrspace(1)*>
%arrayidx = getelementptr i32 addrspace(1)* %tmp1, i32 0 ; <i32 addrspace(1)*> [#uses=1]
%tmp2 = load i32 addrspace(1)* %arrayidx ; <i32> [#uses=1]
store i32 %tmp2, i32* %res
br label %if.end
if.else: ; preds = %entry
%tmp3 = load i32** %pointer2.addr ; <i32*> [#uses=1]
%arrayidx4 = getelementptr i32* %tmp3, i32 0 ; <i32*> [#uses=1]
%tmp5 = load i32* %arrayidx4 ; <i32> [#uses=1]
store i32 %tmp5, i32* %res
br label %if.end
}
; PR4413
declare i32 @ext()
; CHECK: @test17
define i32 @test17(i1 %a) {
entry:
br i1 %a, label %bb1, label %bb2
bb1: ; preds = %entry
%0 = tail call i32 @ext() ; <i32> [#uses=1]
br label %bb2
bb2: ; preds = %bb1, %entry
%cond = phi i1 [ true, %bb1 ], [ false, %entry ] ; <i1> [#uses=1]
; CHECK-NOT: %val = phi i32 [ %0, %bb1 ], [ 0, %entry ]
%val = phi i32 [ %0, %bb1 ], [ 0, %entry ] ; <i32> [#uses=1]
%res = select i1 %cond, i32 %val, i32 0 ; <i32> [#uses=1]
; CHECK: ret i32 %cond
ret i32 %res
}
define i1 @test18(i1 %cond) {
%zero = alloca i32
%one = alloca i32
br i1 %cond, label %true, label %false
true:
br label %ret
false:
br label %ret
ret:
%ptr = phi i32* [ %zero, %true ] , [ %one, %false ]
%isnull = icmp eq i32* %ptr, null
ret i1 %isnull
; CHECK: @test18
; CHECK: ret i1 false
}
define i1 @test19(i1 %cond, double %x) {
br i1 %cond, label %true, label %false
true:
br label %ret
false:
br label %ret
ret:
%p = phi double [ %x, %true ], [ 0x7FF0000000000000, %false ]; RHS = +infty
%cmp = fcmp ule double %x, %p
ret i1 %cmp
; CHECK: @test19
; CHECK: ret i1 true
}
define i1 @test20(i1 %cond) {
%a = alloca i32
%b = alloca i32
%c = alloca i32
br i1 %cond, label %true, label %false
true:
br label %ret
false:
br label %ret
ret:
%p = phi i32* [ %a, %true ], [ %b, %false ]
%r = icmp eq i32* %p, %c
ret i1 %r
; CHECK: @test20
; CHECK: ret i1 false
}
define i1 @test21(i1 %c1, i1 %c2) {
%a = alloca i32
%b = alloca i32
%c = alloca i32
br i1 %c1, label %true, label %false
true:
br label %loop
false:
br label %loop
loop:
%p = phi i32* [ %a, %true ], [ %b, %false ], [ %p, %loop ]
%r = icmp eq i32* %p, %c
br i1 %c2, label %ret, label %loop
ret:
ret i1 %r
; CHECK: @test21
; CHECK: ret i1 false
}
define void @test22() {
; CHECK: @test22
entry:
br label %loop
loop:
%phi = phi i32 [ 0, %entry ], [ %y, %loop ]
%y = add i32 %phi, 1
%o = or i32 %y, %phi
%e = icmp eq i32 %o, %y
br i1 %e, label %loop, label %ret
; CHECK: br i1 %e
ret:
ret void
}