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      1 ; This test makes sure that these instructions are properly eliminated.
      2 ;
      3 ; RUN: opt < %s -instcombine -S | FileCheck %s
      4 
      5 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"
      6 
      7 define i32 @test1(i32 %A, i1 %b) {
      8 BB0:
      9         br i1 %b, label %BB1, label %BB2
     10 
     11 BB1:
     12         ; Combine away one argument PHI nodes
     13         %B = phi i32 [ %A, %BB0 ]               
     14         ret i32 %B
     15 
     16 BB2:
     17         ret i32 %A
     18 ; CHECK-LABEL: @test1(
     19 ; CHECK: BB1:
     20 ; CHECK-NEXT: ret i32 %A
     21 }
     22 
     23 define i32 @test2(i32 %A, i1 %b) {
     24 BB0:
     25         br i1 %b, label %BB1, label %BB2
     26 
     27 BB1:
     28         br label %BB2
     29 
     30 BB2:
     31         ; Combine away PHI nodes with same values
     32         %B = phi i32 [ %A, %BB0 ], [ %A, %BB1 ]         
     33         ret i32 %B
     34 ; CHECK-LABEL: @test2(
     35 ; CHECK: BB2:
     36 ; CHECK-NEXT: ret i32 %A
     37 }
     38 
     39 define i32 @test3(i32 %A, i1 %b) {
     40 BB0:
     41         br label %Loop
     42 
     43 Loop:
     44         ; PHI has same value always.
     45         %B = phi i32 [ %A, %BB0 ], [ %B, %Loop ]
     46         br i1 %b, label %Loop, label %Exit
     47 
     48 Exit:
     49         ret i32 %B
     50 ; CHECK-LABEL: @test3(
     51 ; CHECK: Exit:
     52 ; CHECK-NEXT: ret i32 %A
     53 }
     54 
     55 define i32 @test4(i1 %b) {
     56 BB0:
     57         ; Loop is unreachable
     58         ret i32 7
     59 
     60 Loop:           ; preds = %L2, %Loop
     61         ; PHI has same value always.
     62         %B = phi i32 [ %B, %L2 ], [ %B, %Loop ]         
     63         br i1 %b, label %L2, label %Loop
     64 
     65 L2:             ; preds = %Loop
     66         br label %Loop
     67 ; CHECK-LABEL: @test4(
     68 ; CHECK: Loop:
     69 ; CHECK-NEXT: br i1 %b
     70 }
     71 
     72 define i32 @test5(i32 %A, i1 %b) {
     73 BB0:
     74         br label %Loop
     75 
     76 Loop:           ; preds = %Loop, %BB0
     77         ; PHI has same value always.
     78         %B = phi i32 [ %A, %BB0 ], [ undef, %Loop ]             
     79         br i1 %b, label %Loop, label %Exit
     80 
     81 Exit:           ; preds = %Loop
     82         ret i32 %B
     83 ; CHECK-LABEL: @test5(
     84 ; CHECK: Loop:
     85 ; CHECK-NEXT: br i1 %b
     86 ; CHECK: Exit:
     87 ; CHECK-NEXT: ret i32 %A
     88 }
     89 
     90 define i32 @test6(i16 %A, i1 %b) {
     91 BB0:
     92         %X = zext i16 %A to i32              
     93         br i1 %b, label %BB1, label %BB2
     94 
     95 BB1:           
     96         %Y = zext i16 %A to i32              
     97         br label %BB2
     98 
     99 BB2:           
    100         ;; Suck casts into phi
    101         %B = phi i32 [ %X, %BB0 ], [ %Y, %BB1 ]         
    102         ret i32 %B
    103 ; CHECK-LABEL: @test6(
    104 ; CHECK: BB2:
    105 ; CHECK: zext i16 %A to i32
    106 ; CHECK-NEXT: ret i32
    107 }
    108 
    109 define i32 @test7(i32 %A, i1 %b) {
    110 BB0:
    111         br label %Loop
    112 
    113 Loop:           ; preds = %Loop, %BB0
    114         ; PHI is dead.
    115         %B = phi i32 [ %A, %BB0 ], [ %C, %Loop ]                
    116         %C = add i32 %B, 123            
    117         br i1 %b, label %Loop, label %Exit
    118 
    119 Exit:           ; preds = %Loop
    120         ret i32 0
    121 ; CHECK-LABEL: @test7(
    122 ; CHECK: Loop:
    123 ; CHECK-NEXT: br i1 %b
    124 }
    125 
    126 define i32* @test8({ i32, i32 } *%A, i1 %b) {
    127 BB0:
    128         %X = getelementptr inbounds { i32, i32 } *%A, i32 0, i32 1
    129         br i1 %b, label %BB1, label %BB2
    130 
    131 BB1:
    132         %Y = getelementptr { i32, i32 } *%A, i32 0, i32 1
    133         br label %BB2
    134 
    135 BB2:
    136         ;; Suck GEPs into phi
    137         %B = phi i32* [ %X, %BB0 ], [ %Y, %BB1 ]
    138         ret i32* %B
    139 ; CHECK-LABEL: @test8(
    140 ; CHECK-NOT: phi
    141 ; CHECK: BB2:
    142 ; CHECK-NEXT: %B = getelementptr { i32, i32 }* %A 
    143 ; CHECK-NEXT: ret i32* %B
    144 }
    145 
    146 define i32 @test9(i32* %A, i32* %B) {
    147 entry:
    148   %c = icmp eq i32* %A, null
    149   br i1 %c, label %bb1, label %bb
    150 
    151 bb:
    152   %C = load i32* %B, align 1
    153   br label %bb2
    154 
    155 bb1:
    156   %D = load i32* %A, align 1
    157   br label %bb2
    158 
    159 bb2:
    160   %E = phi i32 [ %C, %bb ], [ %D, %bb1 ]
    161   ret i32 %E
    162 ; CHECK-LABEL: @test9(
    163 ; CHECK:       bb2:
    164 ; CHECK-NEXT:        phi i32* [ %B, %bb ], [ %A, %bb1 ]
    165 ; CHECK-NEXT:   %E = load i32* %{{[^,]*}}, align 1
    166 ; CHECK-NEXT:   ret i32 %E
    167 
    168 }
    169 
    170 define i32 @test10(i32* %A, i32* %B) {
    171 entry:
    172   %c = icmp eq i32* %A, null
    173   br i1 %c, label %bb1, label %bb
    174 
    175 bb:
    176   %C = load i32* %B, align 16
    177   br label %bb2
    178 
    179 bb1:
    180   %D = load i32* %A, align 32
    181   br label %bb2
    182 
    183 bb2:
    184   %E = phi i32 [ %C, %bb ], [ %D, %bb1 ]
    185   ret i32 %E
    186 ; CHECK-LABEL: @test10(
    187 ; CHECK:       bb2:
    188 ; CHECK-NEXT:        phi i32* [ %B, %bb ], [ %A, %bb1 ]
    189 ; CHECK-NEXT:   %E = load i32* %{{[^,]*}}, align 16
    190 ; CHECK-NEXT:   ret i32 %E
    191 }
    192 
    193 
    194 ; PR1777
    195 declare i1 @test11a()
    196 
    197 define i1 @test11() {
    198 entry:
    199   %a = alloca i32
    200   %i = ptrtoint i32* %a to i64
    201   %b = call i1 @test11a()
    202   br i1 %b, label %one, label %two
    203 
    204 one:
    205   %x = phi i64 [%i, %entry], [%y, %two]
    206   %c = call i1 @test11a()
    207   br i1 %c, label %two, label %end
    208 
    209 two:
    210   %y = phi i64 [%i, %entry], [%x, %one]
    211   %d = call i1 @test11a()
    212   br i1 %d, label %one, label %end
    213 
    214 end:
    215   %f = phi i64 [ %x, %one], [%y, %two]
    216   ; Change the %f to %i, and the optimizer suddenly becomes a lot smarter
    217   ; even though %f must equal %i at this point
    218   %g = inttoptr i64 %f to i32*
    219   store i32 10, i32* %g
    220   %z = call i1 @test11a()
    221   ret i1 %z
    222 ; CHECK-LABEL: @test11(
    223 ; CHECK-NOT: phi i32
    224 ; CHECK: ret i1 %z
    225 }
    226 
    227 
    228 define i64 @test12(i1 %cond, i8* %Ptr, i64 %Val) {
    229 entry:
    230   %tmp41 = ptrtoint i8* %Ptr to i64
    231   %tmp42 = zext i64 %tmp41 to i128
    232   br i1 %cond, label %end, label %two
    233 
    234 two:
    235   %tmp36 = zext i64 %Val to i128            ; <i128> [#uses=1]
    236   %tmp37 = shl i128 %tmp36, 64                    ; <i128> [#uses=1]
    237   %ins39 = or i128 %tmp42, %tmp37                 ; <i128> [#uses=1]
    238   br label %end
    239 
    240 end:
    241   %tmp869.0 = phi i128 [ %tmp42, %entry ], [ %ins39, %two ]
    242   %tmp32 = trunc i128 %tmp869.0 to i64            ; <i64> [#uses=1]
    243   %tmp29 = lshr i128 %tmp869.0, 64                ; <i128> [#uses=1]
    244   %tmp30 = trunc i128 %tmp29 to i64               ; <i64> [#uses=1]
    245 
    246   %tmp2 = add i64 %tmp32, %tmp30
    247   ret i64 %tmp2
    248 ; CHECK-LABEL: @test12(
    249 ; CHECK-NOT: zext
    250 ; CHECK: end:
    251 ; CHECK-NEXT: phi i64 [ 0, %entry ], [ %Val, %two ]
    252 ; CHECK-NOT: phi
    253 ; CHECK: ret i64
    254 }
    255 
    256 declare void @test13f(double, i32)
    257 
    258 define void @test13(i1 %cond, i32 %V1, double %Vald) {
    259 entry:
    260   %tmp42 = zext i32 %V1 to i128
    261   br i1 %cond, label %end, label %two
    262 
    263 two:
    264   %Val = bitcast double %Vald to i64
    265   %tmp36 = zext i64 %Val to i128            ; <i128> [#uses=1]
    266   %tmp37 = shl i128 %tmp36, 64                    ; <i128> [#uses=1]
    267   %ins39 = or i128 %tmp42, %tmp37                 ; <i128> [#uses=1]
    268   br label %end
    269 
    270 end:
    271   %tmp869.0 = phi i128 [ %tmp42, %entry ], [ %ins39, %two ]
    272   %tmp32 = trunc i128 %tmp869.0 to i32
    273   %tmp29 = lshr i128 %tmp869.0, 64                ; <i128> [#uses=1]
    274   %tmp30 = trunc i128 %tmp29 to i64               ; <i64> [#uses=1]
    275   %tmp31 = bitcast i64 %tmp30 to double
    276   
    277   call void @test13f(double %tmp31, i32 %tmp32)
    278   ret void
    279 ; CHECK-LABEL: @test13(
    280 ; CHECK-NOT: zext
    281 ; CHECK: end:
    282 ; CHECK-NEXT: phi double [ 0.000000e+00, %entry ], [ %Vald, %two ]
    283 ; CHECK-NEXT: call void @test13f(double {{[^,]*}}, i32 %V1)
    284 ; CHECK: ret void
    285 }
    286 
    287 define i640 @test14a(i320 %A, i320 %B, i1 %b1) {
    288 BB0:
    289         %a = zext i320 %A to i640
    290         %b = zext i320 %B to i640
    291         br label %Loop
    292 
    293 Loop:
    294         %C = phi i640 [ %a, %BB0 ], [ %b, %Loop ]             
    295         br i1 %b1, label %Loop, label %Exit
    296 
    297 Exit:           ; preds = %Loop
    298         ret i640 %C
    299 ; CHECK-LABEL: @test14a(
    300 ; CHECK: Loop:
    301 ; CHECK-NEXT: phi i320
    302 }
    303 
    304 define i160 @test14b(i320 %A, i320 %B, i1 %b1) {
    305 BB0:
    306         %a = trunc i320 %A to i160
    307         %b = trunc i320 %B to i160
    308         br label %Loop
    309 
    310 Loop:
    311         %C = phi i160 [ %a, %BB0 ], [ %b, %Loop ]             
    312         br i1 %b1, label %Loop, label %Exit
    313 
    314 Exit:           ; preds = %Loop
    315         ret i160 %C
    316 ; CHECK-LABEL: @test14b(
    317 ; CHECK: Loop:
    318 ; CHECK-NEXT: phi i160
    319 }
    320 
    321 declare i64 @test15a(i64)
    322 
    323 define i64 @test15b(i64 %A, i1 %b) {
    324 ; CHECK-LABEL: @test15b(
    325 entry:
    326   %i0 = zext i64 %A to i128
    327   %i1 = shl i128 %i0, 64
    328   %i = or i128 %i1, %i0
    329   br i1 %b, label %one, label %two
    330 ; CHECK: entry:
    331 ; CHECK-NEXT: br i1 %b
    332 
    333 one:
    334   %x = phi i128 [%i, %entry], [%y, %two]
    335   %x1 = lshr i128 %x, 64
    336   %x2 = trunc i128 %x1 to i64
    337   %c = call i64 @test15a(i64 %x2)
    338   %c1 = zext i64 %c to i128
    339   br label %two
    340 
    341 ; CHECK: one:
    342 ; CHECK-NEXT: phi i64
    343 ; CHECK-NEXT: %c = call i64 @test15a
    344 
    345 two:
    346   %y = phi i128 [%i, %entry], [%c1, %one]
    347   %y1 = lshr i128 %y, 64
    348   %y2 = trunc i128 %y1 to i64
    349   %d = call i64 @test15a(i64 %y2)
    350   %d1 = trunc i64 %d to i1
    351   br i1 %d1, label %one, label %end
    352 
    353 ; CHECK: two:
    354 ; CHECK-NEXT: phi i64
    355 ; CHECK-NEXT: phi i64
    356 ; CHECK-NEXT: %d = call i64 @test15a
    357 
    358 end:
    359   %g = trunc i128 %y to i64
    360   ret i64 %g
    361 ; CHECK: end: 
    362 ; CHECK-NEXT: ret i64
    363 }
    364 
    365 ; PR6512 - Shouldn't merge loads from different addr spaces.
    366 define i32 @test16(i32 addrspace(1)* %pointer1, i32 %flag, i32* %pointer2)
    367 nounwind {
    368 entry:
    369   %retval = alloca i32, align 4                   ; <i32*> [#uses=2]
    370   %pointer1.addr = alloca i32 addrspace(1)*, align 4 ; <i32 addrspace(1)**>
    371   %flag.addr = alloca i32, align 4                ; <i32*> [#uses=2]
    372   %pointer2.addr = alloca i32*, align 4           ; <i32**> [#uses=2]
    373   %res = alloca i32, align 4                      ; <i32*> [#uses=4]
    374   store i32 addrspace(1)* %pointer1, i32 addrspace(1)** %pointer1.addr
    375   store i32 %flag, i32* %flag.addr
    376   store i32* %pointer2, i32** %pointer2.addr
    377   store i32 10, i32* %res
    378   %tmp = load i32* %flag.addr                     ; <i32> [#uses=1]
    379   %tobool = icmp ne i32 %tmp, 0                   ; <i1> [#uses=1]
    380   br i1 %tobool, label %if.then, label %if.else
    381 
    382 return:                                           ; preds = %if.end
    383   %tmp7 = load i32* %retval                       ; <i32> [#uses=1]
    384   ret i32 %tmp7
    385 
    386 if.end:                                           ; preds = %if.else, %if.then
    387   %tmp6 = load i32* %res                          ; <i32> [#uses=1]
    388   store i32 %tmp6, i32* %retval
    389   br label %return
    390 
    391 if.then:                                          ; preds = %entry
    392   %tmp1 = load i32 addrspace(1)** %pointer1.addr  ; <i32 addrspace(1)*>
    393   %arrayidx = getelementptr i32 addrspace(1)* %tmp1, i32 0 ; <i32 addrspace(1)*> [#uses=1]
    394   %tmp2 = load i32 addrspace(1)* %arrayidx        ; <i32> [#uses=1]
    395   store i32 %tmp2, i32* %res
    396   br label %if.end
    397 
    398 if.else:                                          ; preds = %entry
    399   %tmp3 = load i32** %pointer2.addr               ; <i32*> [#uses=1]
    400   %arrayidx4 = getelementptr i32* %tmp3, i32 0    ; <i32*> [#uses=1]
    401   %tmp5 = load i32* %arrayidx4                    ; <i32> [#uses=1]
    402   store i32 %tmp5, i32* %res
    403   br label %if.end
    404 }
    405 
    406 ; PR4413
    407 declare i32 @ext()
    408 ; CHECK-LABEL: @test17(
    409 define i32 @test17(i1 %a) {
    410 entry:
    411     br i1 %a, label %bb1, label %bb2
    412 
    413 bb1:        ; preds = %entry
    414     %0 = tail call i32 @ext()        ; <i32> [#uses=1]
    415     br label %bb2
    416 
    417 bb2:        ; preds = %bb1, %entry
    418     %cond = phi i1 [ true, %bb1 ], [ false, %entry ]        ; <i1> [#uses=1]
    419 ; CHECK-NOT: %val = phi i32 [ %0, %bb1 ], [ 0, %entry ]
    420     %val = phi i32 [ %0, %bb1 ], [ 0, %entry ]        ; <i32> [#uses=1]
    421     %res = select i1 %cond, i32 %val, i32 0        ; <i32> [#uses=1]
    422 ; CHECK: ret i32 %cond
    423     ret i32 %res
    424 }
    425 
    426 define i1 @test18(i1 %cond) {
    427   %zero = alloca i32
    428   %one = alloca i32
    429   br i1 %cond, label %true, label %false
    430 true:
    431   br label %ret
    432 false:
    433   br label %ret
    434 ret:
    435   %ptr = phi i32* [ %zero, %true ] , [ %one, %false ]
    436   %isnull = icmp eq i32* %ptr, null
    437   ret i1 %isnull
    438 ; CHECK-LABEL: @test18(
    439 ; CHECK: ret i1 false
    440 }
    441 
    442 define i1 @test19(i1 %cond, double %x) {
    443   br i1 %cond, label %true, label %false
    444 true:
    445   br label %ret
    446 false:
    447   br label %ret
    448 ret:
    449   %p = phi double [ %x, %true ], [ 0x7FF0000000000000, %false ]; RHS = +infty
    450   %cmp = fcmp ule double %x, %p
    451   ret i1 %cmp
    452 ; CHECK-LABEL: @test19(
    453 ; CHECK: ret i1 true
    454 }
    455 
    456 define i1 @test20(i1 %cond) {
    457   %a = alloca i32
    458   %b = alloca i32
    459   %c = alloca i32
    460   br i1 %cond, label %true, label %false
    461 true:
    462   br label %ret
    463 false:
    464   br label %ret
    465 ret:
    466   %p = phi i32* [ %a, %true ], [ %b, %false ]
    467   %r = icmp eq i32* %p, %c
    468   ret i1 %r
    469 ; CHECK-LABEL: @test20(
    470 ; CHECK: ret i1 false
    471 }
    472 
    473 define i1 @test21(i1 %c1, i1 %c2) {
    474   %a = alloca i32
    475   %b = alloca i32
    476   %c = alloca i32
    477   br i1 %c1, label %true, label %false
    478 true:
    479   br label %loop
    480 false:
    481   br label %loop
    482 loop:
    483   %p = phi i32* [ %a, %true ], [ %b, %false ], [ %p, %loop ]
    484   %r = icmp eq i32* %p, %c
    485   br i1 %c2, label %ret, label %loop
    486 ret:
    487   ret i1 %r
    488 ; CHECK-LABEL: @test21(
    489 ; CHECK: ret i1 false
    490 }
    491 
    492 define void @test22() {
    493 ; CHECK-LABEL: @test22(
    494 entry:
    495   br label %loop
    496 loop:
    497   %phi = phi i32 [ 0, %entry ], [ %y, %loop ]
    498   %y = add i32 %phi, 1
    499   %o = or i32 %y, %phi
    500   %e = icmp eq i32 %o, %y
    501   br i1 %e, label %loop, label %ret
    502 ; CHECK: br i1 %e
    503 ret:
    504   ret void
    505 }
    506 
    507 define i32 @test23(i32 %A, i1 %b, i32 * %P) {
    508 BB0:
    509         br label %Loop
    510 
    511 Loop:           ; preds = %Loop, %BB0
    512         ; PHI has same value always.
    513         %B = phi i32 [ %A, %BB0 ], [ 42, %Loop ]
    514         %D = add i32 %B, 19
    515         store i32 %D, i32* %P
    516         br i1 %b, label %Loop, label %Exit
    517 
    518 Exit:           ; preds = %Loop
    519         %E = add i32 %B, 19
    520         ret i32 %E
    521 ; CHECK-LABEL: @test23(
    522 ; CHECK: %phitmp = add i32 %A, 19
    523 ; CHECK: Loop:
    524 ; CHECK-NEXT: %B = phi i32 [ %phitmp, %BB0 ], [ 61, %Loop ]
    525 ; CHECK: Exit:
    526 ; CHECK-NEXT: ret i32 %B
    527 }
    528 
    529 define i32 @test24(i32 %A, i1 %cond) {
    530 BB0:
    531         %X = add nuw nsw i32 %A, 1
    532         br i1 %cond, label %BB1, label %BB2
    533 
    534 BB1:
    535         %Y = add nuw i32 %A, 1
    536         br label %BB2
    537 
    538 BB2:
    539         %C = phi i32 [ %X, %BB0 ], [ %Y, %BB1 ]
    540         ret i32 %C
    541 ; CHECK-LABEL: @test24(
    542 ; CHECK-NOT: phi
    543 ; CHECK: BB2:
    544 ; CHECK-NEXT: %C = add nuw i32 %A, 1
    545 ; CHECK-NEXT: ret i32 %C
    546 }
    547 
    548 ; Same as test11, but used to be missed due to a bug.
    549 declare i1 @test25a()
    550 
    551 define i1 @test25() {
    552 entry:
    553   %a = alloca i32
    554   %i = ptrtoint i32* %a to i64
    555   %b = call i1 @test25a()
    556   br i1 %b, label %one, label %two
    557 
    558 one:
    559   %x = phi i64 [%y, %two], [%i, %entry]
    560   %c = call i1 @test25a()
    561   br i1 %c, label %two, label %end
    562 
    563 two:
    564   %y = phi i64 [%x, %one], [%i, %entry]
    565   %d = call i1 @test25a()
    566   br i1 %d, label %one, label %end
    567 
    568 end:
    569   %f = phi i64 [ %x, %one], [%y, %two]
    570   ; Change the %f to %i, and the optimizer suddenly becomes a lot smarter
    571   ; even though %f must equal %i at this point
    572   %g = inttoptr i64 %f to i32*
    573   store i32 10, i32* %g
    574   %z = call i1 @test25a()
    575   ret i1 %z
    576 ; CHECK-LABEL: @test25(
    577 ; CHECK-NOT: phi i32
    578 ; CHECK: ret i1 %z
    579 }
    580 
    581 declare i1 @test26a()
    582 
    583 define i1 @test26(i32 %n) {
    584 entry:
    585   %a = alloca i32
    586   %i = ptrtoint i32* %a to i64
    587   %b = call i1 @test26a()
    588   br label %one
    589 
    590 one:
    591   %x = phi i64 [%y, %two], [%w, %three], [%i, %entry]
    592   %c = call i1 @test26a()
    593   switch i32 %n, label %end [
    594           i32 2, label %two
    595           i32 3, label %three
    596   ]
    597 
    598 two:
    599   %y = phi i64 [%x, %one], [%w, %three]
    600   %d = call i1 @test26a()
    601   switch i32 %n, label %end [
    602           i32 10, label %one
    603           i32 30, label %three
    604   ]
    605 
    606 three:
    607   %w = phi i64 [%y, %two], [%x, %one]
    608   %e = call i1 @test26a()
    609   br i1 %e, label %one, label %two
    610 
    611 end:
    612   %f = phi i64 [ %x, %one], [%y, %two]
    613   ; Change the %f to %i, and the optimizer suddenly becomes a lot smarter
    614   ; even though %f must equal %i at this point
    615   %g = inttoptr i64 %f to i32*
    616   store i32 10, i32* %g
    617   %z = call i1 @test26a()
    618   ret i1 %z
    619 ; CHECK-LABEL: @test26(
    620 ; CHECK-NOT: phi i32
    621 ; CHECK: ret i1 %z
    622 }
    623 
    624 ; CHECK-LABEL: @test27(
    625 ; CHECK: ret i32 undef
    626 define i32 @test27(i1 %b) {
    627 entry:
    628   br label %done
    629 done:
    630   %y = phi i32 [ undef, %entry ]
    631   ret i32 %y
    632 }
    633