1 ; RUN: opt -S -analyze -scalar-evolution < %s 2>&1 | FileCheck %s 2 3 ; umin is represented using -1 * umax in scalar evolution. -1 is considered as the 4 ; constant of the multiply expression (-1 * ((-1 + (-1 * %a)) umax (-1 + (-1 * %b)))). 5 ; Returns the greatest power of 2 divisor by evaluating the minimal trailing zeros 6 ; for the trip count expression. 7 ; 8 ; int foo(uint32_t a, uint32_t b, uint32_t *c) { 9 ; for (uint32_t i = 0; i < (uint32_t)(a < b ? a : b) + 1; i++) 10 ; c[i] = i; 11 ; return 0; 12 ; } 13 ; 14 ; CHECK: Loop %for.body: Trip multiple is 1 15 16 define i32 @foo(i32 %a, i32 %b, i32* %c) { 17 entry: 18 %cmp = icmp ult i32 %a, %b 19 %cond = select i1 %cmp, i32 %a, i32 %b 20 %add = add i32 %cond, 1 21 %cmp18 = icmp eq i32 %add, 0 22 br i1 %cmp18, label %for.cond.cleanup, label %for.body.preheader 23 24 for.body.preheader: ; preds = %entry 25 br label %for.body 26 27 for.cond.cleanup.loopexit: ; preds = %for.body 28 br label %for.cond.cleanup 29 30 for.cond.cleanup: ; preds = %for.cond.cleanup.loopexit, %entry 31 ret i32 0 32 33 for.body: ; preds = %for.body.preheader, %for.body 34 %i.09 = phi i32 [ %inc, %for.body ], [ 0, %for.body.preheader ] 35 %arrayidx = getelementptr inbounds i32, i32* %c, i32 %i.09 36 store i32 %i.09, i32* %arrayidx, align 4 37 %inc = add nuw i32 %i.09, 1 38 %cmp1 = icmp ult i32 %inc, %add 39 br i1 %cmp1, label %for.body, label %for.cond.cleanup.loopexit 40 } 41 42 ; Overflow may happen for the multiply expression n * 3, verify that trip 43 ; multiple is set to 1 if NUW/NSW are not set. 44 ; 45 ; __attribute__((noinline)) void a(unsigned n) { 46 ; #pragma unroll(3) 47 ; for (unsigned i = 0; i != n * 3; ++i) 48 ; printf("TEST%u\n", i); 49 ; } 50 ; int main() { a(2863311531U); } 51 ; 52 ; CHECK: Loop %for.body: Trip multiple is 1 53 54 @.str2 = private unnamed_addr constant [8 x i8] c"TEST%u\0A\00", align 1 55 56 define void @foo2(i32 %n) { 57 entry: 58 %mul = mul i32 %n, 3 59 %cmp4 = icmp eq i32 %mul, 0 60 br i1 %cmp4, label %for.cond.cleanup, label %for.body.preheader 61 62 for.body.preheader: ; preds = %entry 63 br label %for.body 64 65 for.cond.cleanup.loopexit: ; preds = %for.body 66 br label %for.cond.cleanup 67 68 for.cond.cleanup: ; preds = %for.cond.cleanup.loopexit, %entry 69 ret void 70 71 for.body: ; preds = %for.body.preheader, %for.body 72 %i.05 = phi i32 [ %inc, %for.body ], [ 0, %for.body.preheader ] 73 %call = tail call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([8 x i8], [8 x i8]* @.str2, i32 0, i32 0), i32 %i.05) 74 %inc = add nuw i32 %i.05, 1 75 %cmp = icmp eq i32 %inc, %mul 76 br i1 %cmp, label %for.cond.cleanup.loopexit, label %for.body 77 } 78 79 declare i32 @printf(i8* nocapture readonly, ...) 80 81 82 ; If we couldn't prove no overflow for the multiply expression 24 * n, 83 ; returns the greatest power of 2 divisor. If overflows happens 84 ; the trip count is still divisible by the greatest power of 2 divisor. 85 ; 86 ; CHECK: Loop %l3: Trip multiple is 8 87 88 declare void @f() 89 90 define i32 @foo3(i32 %n) { 91 entry: 92 %loop_ctl = mul i32 %n, 24 93 br label %l3 94 95 l3: 96 %x.0 = phi i32 [ 0, %entry ], [ %inc, %l3 ] 97 call void @f() 98 %inc = add i32 %x.0, 1 99 %exitcond = icmp eq i32 %inc, %loop_ctl 100 br i1 %exitcond, label %exit, label %l3 101 102 exit: 103 ret i32 0 104 } 105 106 ; If the trip count is a constant, verify that we obtained the trip 107 ; count itself. For huge trip counts, or zero, we return 1. 108 ; 109 ; CHECK: Loop %l3: Trip multiple is 3 110 111 define i32 @foo4(i32 %n) { 112 entry: 113 br label %l3 114 115 l3: 116 %x.0 = phi i32 [ 0, %entry ], [ %inc, %l3 ] 117 call void @f() 118 %inc = add i32 %x.0, 1 119 %exitcond = icmp eq i32 %inc, 3 120 br i1 %exitcond, label %exit, label %l3 121 122 exit: 123 ret i32 0 124 } 125 126
