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,+,4} 6 7define void @foo(i32* nocapture %d, i32 %n) nounwind { 8entry: 9 %0 = icmp sgt i32 %n, 0 ; <i1> [#uses=1] 10 br i1 %0, label %bb.nph, label %return 11 12bb.nph: ; preds = %entry 13 br label %bb 14 15bb: ; 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, 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 26bb1: ; preds = %bb 27 %6 = icmp slt i32 %5, %n ; <i1> [#uses=1] 28 br i1 %6, label %bb, label %bb1.return_crit_edge 29 30bb1.return_crit_edge: ; preds = %bb1 31 br label %return 32 33return: ; 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 47define i32 @main() nounwind { 48entry: 49 br label %for.cond 50 51for.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 56for.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 63for.inc: ; preds = %for.body 64 %add = add nsw i32 %g_4.0, 1 ; <i32> [#uses=1] 65 br label %for.cond 66 67for.end: ; preds = %for.body, %for.cond 68 %call = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i64 0, i64 0), i32 %g_4.0) nounwind ; <i32> [#uses=0] 69 ret i32 0 70} 71 72declare i32 @printf(i8*, ...) 73 74define void @test(i8* %a, i32 %n) nounwind { 75entry: 76 %cmp1 = icmp sgt i32 %n, 0 77 br i1 %cmp1, label %for.body.lr.ph, label %for.end 78 79for.body.lr.ph: ; preds = %entry 80 %tmp = zext i32 %n to i64 81 br label %for.body 82 83for.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, 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 91for.cond.for.end_crit_edge: ; preds = %for.body 92 br label %for.end 93 94for.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 108define i32 @pr19799() { 109entry: 110 store i32 -1, i32* @a, align 4 111 br label %for.body.i 112 113for.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 119for.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 124bar.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 134define i32 @pr18886() { 135entry: 136 store i64 -21, i64* @aa, align 8 137 br label %for.body 138 139for.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 145for.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 150return: 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 164define i32 @cannot_compute_mustexit() { 165entry: 166 store i32 -1, i32* @a, align 4 167 br label %for.body.i 168 169for.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 175for.cond.i: ; preds = %for.body.i 176 store i32 %add.i.i, i32* @a, align 4 177 %ld = load volatile i32, i32* @b 178 %cmp.i = icmp ne i32 %ld, 0 179 br i1 %cmp.i, label %for.body.i, label %bar.exit 180 181bar.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 191define i32 @two_mustexit() { 192entry: 193 store i32 -1, i32* @a, align 4 194 br label %for.body.i 195 196for.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 202for.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 207bar.exit: ; preds = %for.cond.i, %for.body.i 208 ret i32 0 209} 210