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      1 ; RUN: opt < %s -analyze -scalar-evolution | FileCheck %s
      2 
      3 ; ScalarEvolution should be able to understand the loop and eliminate the casts.
      4 
      5 ; CHECK: {%d,+,sizeof(i32)}
      6 
      7 define void @foo(i32* nocapture %d, i32 %n) nounwind {
      8 entry:
      9 	%0 = icmp sgt i32 %n, 0		; <i1> [#uses=1]
     10 	br i1 %0, label %bb.nph, label %return
     11 
     12 bb.nph:		; preds = %entry
     13 	br label %bb
     14 
     15 bb:		; preds = %bb1, %bb.nph
     16 	%i.02 = phi i32 [ %5, %bb1 ], [ 0, %bb.nph ]		; <i32> [#uses=2]
     17 	%p.01 = phi i8 [ %4, %bb1 ], [ -1, %bb.nph ]		; <i8> [#uses=2]
     18 	%1 = sext i8 %p.01 to i32		; <i32> [#uses=1]
     19 	%2 = sext i32 %i.02 to i64		; <i64> [#uses=1]
     20 	%3 = getelementptr i32* %d, i64 %2		; <i32*> [#uses=1]
     21 	store i32 %1, i32* %3, align 4
     22 	%4 = add i8 %p.01, 1		; <i8> [#uses=1]
     23 	%5 = add i32 %i.02, 1		; <i32> [#uses=2]
     24 	br label %bb1
     25 
     26 bb1:		; preds = %bb
     27 	%6 = icmp slt i32 %5, %n		; <i1> [#uses=1]
     28 	br i1 %6, label %bb, label %bb1.return_crit_edge
     29 
     30 bb1.return_crit_edge:		; preds = %bb1
     31 	br label %return
     32 
     33 return:		; preds = %bb1.return_crit_edge, %entry
     34 	ret void
     35 }
     36 
     37 ; ScalarEvolution should be able to find the maximum tripcount
     38 ; of this multiple-exit loop, and if it doesn't know the exact
     39 ; count, it should say so.
     40 
     41 ; PR7845
     42 ; CHECK: Loop %for.cond: <multiple exits> Unpredictable backedge-taken count. 
     43 ; CHECK: Loop %for.cond: max backedge-taken count is 5
     44 
     45 @.str = private constant [4 x i8] c"%d\0A\00"     ; <[4 x i8]*> [#uses=2]
     46 
     47 define i32 @main() nounwind {
     48 entry:
     49   br label %for.cond
     50 
     51 for.cond:                                         ; preds = %for.inc, %entry
     52   %g_4.0 = phi i32 [ 0, %entry ], [ %add, %for.inc ] ; <i32> [#uses=5]
     53   %cmp = icmp slt i32 %g_4.0, 5                   ; <i1> [#uses=1]
     54   br i1 %cmp, label %for.body, label %for.end
     55 
     56 for.body:                                         ; preds = %for.cond
     57   %conv = trunc i32 %g_4.0 to i16                 ; <i16> [#uses=1]
     58   %tobool.not = icmp eq i16 %conv, 0              ; <i1> [#uses=1]
     59   %tobool3 = icmp ne i32 %g_4.0, 0                ; <i1> [#uses=1]
     60   %or.cond = and i1 %tobool.not, %tobool3         ; <i1> [#uses=1]
     61   br i1 %or.cond, label %for.end, label %for.inc
     62 
     63 for.inc:                                          ; preds = %for.body
     64   %add = add nsw i32 %g_4.0, 1                    ; <i32> [#uses=1]
     65   br label %for.cond
     66 
     67 for.end:                                          ; preds = %for.body, %for.cond
     68   %call = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([4 x i8]* @.str, i64 0, i64 0), i32 %g_4.0) nounwind ; <i32> [#uses=0]
     69   ret i32 0
     70 }
     71 
     72 declare i32 @printf(i8*, ...)
     73 
     74 define void @test(i8* %a, i32 %n) nounwind {
     75 entry:
     76   %cmp1 = icmp sgt i32 %n, 0
     77   br i1 %cmp1, label %for.body.lr.ph, label %for.end
     78 
     79 for.body.lr.ph:                                   ; preds = %entry
     80   %tmp = zext i32 %n to i64
     81   br label %for.body
     82 
     83 for.body:                                         ; preds = %for.body, %for.body.lr.ph
     84   %indvar = phi i64 [ %indvar.next, %for.body ], [ 0, %for.body.lr.ph ]
     85   %arrayidx = getelementptr i8* %a, i64 %indvar
     86   store i8 0, i8* %arrayidx, align 1
     87   %indvar.next = add i64 %indvar, 1
     88   %exitcond = icmp ne i64 %indvar.next, %tmp
     89   br i1 %exitcond, label %for.body, label %for.cond.for.end_crit_edge
     90 
     91 for.cond.for.end_crit_edge:                       ; preds = %for.body
     92   br label %for.end
     93 
     94 for.end:                                          ; preds = %for.cond.for.end_crit_edge, %entry
     95   ret void
     96 }
     97 
     98 ; CHECK: Determining loop execution counts for: @test
     99 ; CHECK-NEXT: backedge-taken count is
    100 ; CHECK-NEXT: max backedge-taken count is -1
    101 
    102 ; PR19799: Indvars miscompile due to an incorrect max backedge taken count from SCEV.
    103 ; CHECK-LABEL: @pr19799
    104 ; CHECK: Loop %for.body.i: <multiple exits> Unpredictable backedge-taken count. 
    105 ; CHECK: Loop %for.body.i: max backedge-taken count is 1
    106 @a = common global i32 0, align 4
    107 
    108 define i32 @pr19799() {
    109 entry:
    110   store i32 -1, i32* @a, align 4
    111   br label %for.body.i
    112 
    113 for.body.i:                                       ; preds = %for.cond.i, %entry
    114   %storemerge1.i = phi i32 [ -1, %entry ], [ %add.i.i, %for.cond.i ]
    115   %tobool.i = icmp eq i32 %storemerge1.i, 0
    116   %add.i.i = add nsw i32 %storemerge1.i, 2
    117   br i1 %tobool.i, label %bar.exit, label %for.cond.i
    118 
    119 for.cond.i:                                       ; preds = %for.body.i
    120   store i32 %add.i.i, i32* @a, align 4
    121   %cmp.i = icmp slt i32 %storemerge1.i, 0
    122   br i1 %cmp.i, label %for.body.i, label %bar.exit
    123 
    124 bar.exit:                                         ; preds = %for.cond.i, %for.body.i
    125   ret i32 0
    126 }
    127 
    128 ; PR18886: Indvars miscompile due to an incorrect max backedge taken count from SCEV.
    129 ; CHECK-LABEL: @pr18886
    130 ; CHECK: Loop %for.body: <multiple exits> Unpredictable backedge-taken count. 
    131 ; CHECK: Loop %for.body: max backedge-taken count is 3
    132 @aa = global i64 0, align 8
    133 
    134 define i32 @pr18886() {
    135 entry:
    136   store i64 -21, i64* @aa, align 8
    137   br label %for.body
    138 
    139 for.body:
    140   %storemerge1 = phi i64 [ -21, %entry ], [ %add, %for.cond ]
    141   %tobool = icmp eq i64 %storemerge1, 0
    142   %add = add nsw i64 %storemerge1, 8
    143   br i1 %tobool, label %return, label %for.cond
    144 
    145 for.cond:
    146   store i64 %add, i64* @aa, align 8
    147   %cmp = icmp slt i64 %add, 9
    148   br i1 %cmp, label %for.body, label %return
    149 
    150 return:
    151   %retval.0 = phi i32 [ 1, %for.body ], [ 0, %for.cond ]
    152   ret i32 %retval.0
    153 }
    154 
    155 ; Here we have a must-exit loop latch that is not computable and a
    156 ; may-exit early exit that can only have one non-exiting iteration
    157 ; before the check is forever skipped.
    158 ;
    159 ; CHECK-LABEL: @cannot_compute_mustexit
    160 ; CHECK: Loop %for.body.i: <multiple exits> Unpredictable backedge-taken count. 
    161 ; CHECK: Loop %for.body.i: Unpredictable max backedge-taken count. 
    162 @b = common global i32 0, align 4
    163 
    164 define i32 @cannot_compute_mustexit() {
    165 entry:
    166   store i32 -1, i32* @a, align 4
    167   br label %for.body.i
    168 
    169 for.body.i:                                       ; preds = %for.cond.i, %entry
    170   %storemerge1.i = phi i32 [ -1, %entry ], [ %add.i.i, %for.cond.i ]
    171   %tobool.i = icmp eq i32 %storemerge1.i, 0
    172   %add.i.i = add nsw i32 %storemerge1.i, 2
    173   br i1 %tobool.i, label %bar.exit, label %for.cond.i
    174 
    175 for.cond.i:                                       ; preds = %for.body.i
    176   store i32 %add.i.i, i32* @a, align 4
    177   %ld = load volatile i32* @b
    178   %cmp.i = icmp ne i32 %ld, 0
    179   br i1 %cmp.i, label %for.body.i, label %bar.exit
    180 
    181 bar.exit:                                         ; preds = %for.cond.i, %for.body.i
    182   ret i32 0
    183 }
    184 
    185 ; This loop has two must-exits, both of which dominate the latch. The
    186 ; MaxBECount should be the minimum of them.
    187 ;
    188 ; CHECK-LABEL: @two_mustexit
    189 ; CHECK: Loop %for.body.i: <multiple exits> Unpredictable backedge-taken count. 
    190 ; CHECK: Loop %for.body.i: max backedge-taken count is 1
    191 define i32 @two_mustexit() {
    192 entry:
    193   store i32 -1, i32* @a, align 4
    194   br label %for.body.i
    195 
    196 for.body.i:                                       ; preds = %for.cond.i, %entry
    197   %storemerge1.i = phi i32 [ -1, %entry ], [ %add.i.i, %for.cond.i ]
    198   %tobool.i = icmp sgt i32 %storemerge1.i, 0
    199   %add.i.i = add nsw i32 %storemerge1.i, 2
    200   br i1 %tobool.i, label %bar.exit, label %for.cond.i
    201 
    202 for.cond.i:                                       ; preds = %for.body.i
    203   store i32 %add.i.i, i32* @a, align 4
    204   %cmp.i = icmp slt i32 %storemerge1.i, 3
    205   br i1 %cmp.i, label %for.body.i, label %bar.exit
    206 
    207 bar.exit:                                         ; preds = %for.cond.i, %for.body.i
    208   ret i32 0
    209 }
    210