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      1 ; RUN: opt < %s -basicaa -gvn -dse -S | FileCheck %s
      2 target datalayout = "E-p:64:64:64-a0:0:8-f32:32:32-f64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-v64:64:64-v128:128:128"
      3 
      4 declare void @llvm.lifetime.end(i64, i8* nocapture)
      5 
      6 declare void @external(i32*) 
      7 
      8 define i32 @test0(i8* %P) {
      9   %A = alloca i32
     10   call void @external(i32* %A)
     11   
     12   store i32 0, i32* %A
     13   
     14   call void @llvm.memset.p0i8.i32(i8* %P, i8 0, i32 42, i32 1, i1 false)
     15   
     16   %B = load i32* %A
     17   ret i32 %B
     18   
     19 ; CHECK: @test0
     20 ; CHECK: ret i32 0
     21 }
     22 
     23 define i8 @test1() {
     24 ; CHECK: @test1
     25   %A = alloca i8
     26   %B = alloca i8
     27 
     28   store i8 2, i8* %B  ;; Not written to by memcpy
     29 
     30   call void @llvm.memcpy.p0i8.p0i8.i8(i8* %A, i8* %B, i8 -1, i32 0, i1 false)
     31 
     32   %C = load i8* %B
     33   ret i8 %C
     34 ; CHECK: ret i8 2
     35 }
     36 
     37 define i8 @test2(i8* %P) {
     38 ; CHECK: @test2
     39   %P2 = getelementptr i8* %P, i32 127
     40   store i8 1, i8* %P2  ;; Not dead across memset
     41   call void @llvm.memset.p0i8.i8(i8* %P, i8 2, i8 127, i32 0, i1 false)
     42   %A = load i8* %P2
     43   ret i8 %A
     44 ; CHECK: ret i8 1
     45 }
     46 
     47 define i8 @test2a(i8* %P) {
     48 ; CHECK: @test2
     49   %P2 = getelementptr i8* %P, i32 126
     50   
     51   ;; FIXME: DSE isn't zapping this dead store.
     52   store i8 1, i8* %P2  ;; Dead, clobbered by memset.
     53   
     54   call void @llvm.memset.p0i8.i8(i8* %P, i8 2, i8 127, i32 0, i1 false)
     55   %A = load i8* %P2
     56   ret i8 %A
     57 ; CHECK-NOT: load
     58 ; CHECK: ret i8 2
     59 }
     60 
     61 define void @test3(i8* %P, i8 %X) {
     62 ; CHECK: @test3
     63 ; CHECK-NOT: store
     64 ; CHECK-NOT: %Y
     65   %Y = add i8 %X, 1     ;; Dead, because the only use (the store) is dead.
     66   
     67   %P2 = getelementptr i8* %P, i32 2
     68   store i8 %Y, i8* %P2  ;; Not read by lifetime.end, should be removed.
     69 ; CHECK: store i8 2, i8* %P2
     70   call void @llvm.lifetime.end(i64 1, i8* %P)
     71   store i8 2, i8* %P2
     72 ; CHECK-NOT: store
     73   ret void
     74 ; CHECK: ret void
     75 }
     76 
     77 define void @test3a(i8* %P, i8 %X) {
     78 ; CHECK: @test3a
     79   %Y = add i8 %X, 1     ;; Dead, because the only use (the store) is dead.
     80   
     81   %P2 = getelementptr i8* %P, i32 2
     82   store i8 %Y, i8* %P2
     83 ; CHECK-NEXT: call void @llvm.lifetime.end
     84   call void @llvm.lifetime.end(i64 10, i8* %P)
     85   ret void
     86 ; CHECK-NEXT: ret void
     87 }
     88 
     89 @G1 = external global i32
     90 @G2 = external global [4000 x i32]
     91 
     92 define i32 @test4(i8* %P) {
     93   %tmp = load i32* @G1
     94   call void @llvm.memset.p0i8.i32(i8* bitcast ([4000 x i32]* @G2 to i8*), i8 0, i32 4000, i32 1, i1 false)
     95   %tmp2 = load i32* @G1
     96   %sub = sub i32 %tmp2, %tmp
     97   ret i32 %sub
     98 ; CHECK: @test4
     99 ; CHECK-NOT: load
    100 ; CHECK: memset.p0i8.i32
    101 ; CHECK-NOT: load
    102 ; CHECK: ret i32 0
    103 }
    104 
    105 ; Verify that basicaa is handling variable length memcpy, knowing it doesn't
    106 ; write to G1.
    107 define i32 @test5(i8* %P, i32 %Len) {
    108   %tmp = load i32* @G1
    109   call void @llvm.memcpy.p0i8.p0i8.i32(i8* bitcast ([4000 x i32]* @G2 to i8*), i8* bitcast (i32* @G1 to i8*), i32 %Len, i32 1, i1 false)
    110   %tmp2 = load i32* @G1
    111   %sub = sub i32 %tmp2, %tmp
    112   ret i32 %sub
    113 ; CHECK: @test5
    114 ; CHECK-NOT: load
    115 ; CHECK: memcpy.p0i8.p0i8.i32
    116 ; CHECK-NOT: load
    117 ; CHECK: ret i32 0
    118 }
    119 
    120 define i8 @test6(i8* %p, i8* noalias %a) {
    121   %x = load i8* %a
    122   %t = va_arg i8* %p, float
    123   %y = load i8* %a
    124   %z = add i8 %x, %y
    125   ret i8 %z
    126 ; CHECK: @test6
    127 ; CHECK: load i8* %a
    128 ; CHECK-NOT: load
    129 ; CHECK: ret
    130 }
    131 
    132 ; PR10628
    133 declare void @test7decl(i32* nocapture %x)
    134 define i32 @test7() nounwind uwtable ssp {
    135 entry:
    136   %x = alloca i32, align 4
    137   store i32 0, i32* %x, align 4
    138   %add.ptr = getelementptr inbounds i32* %x, i64 1
    139   call void @test7decl(i32* %add.ptr)
    140   %tmp = load i32* %x, align 4
    141   ret i32 %tmp
    142 ; CHECK: @test7(
    143 ; CHECK: store i32 0
    144 ; CHECK: call void @test7decl
    145 ; CHECK: load i32*
    146 }
    147 
    148 declare void @llvm.memset.p0i8.i32(i8* nocapture, i8, i32, i32, i1) nounwind
    149 declare void @llvm.memset.p0i8.i8(i8* nocapture, i8, i8, i32, i1) nounwind
    150 declare void @llvm.memcpy.p0i8.p0i8.i8(i8* nocapture, i8* nocapture, i8, i32, i1) nounwind
    151 declare void @llvm.memcpy.p0i8.p0i8.i32(i8* nocapture, i8* nocapture, i32, i32, i1) nounwind
    152