126 lines
3.7 KiB
LLVM
126 lines
3.7 KiB
LLVM
; RUN: opt -S -analyze -scalar-evolution < %s 2>&1 | FileCheck %s
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; umin is represented using -1 * umax in scalar evolution. -1 is considered as the
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; constant of the multiply expression (-1 * ((-1 + (-1 * %a)) umax (-1 + (-1 * %b)))).
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; Returns the greatest power of 2 divisor by evaluating the minimal trailing zeros
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; for the trip count expression.
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;
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; int foo(uint32_t a, uint32_t b, uint32_t *c) {
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; for (uint32_t i = 0; i < (uint32_t)(a < b ? a : b) + 1; i++)
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; c[i] = i;
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; return 0;
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; }
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;
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; CHECK: Loop %for.body: Trip multiple is 1
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define i32 @foo(i32 %a, i32 %b, i32* %c) {
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entry:
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%cmp = icmp ult i32 %a, %b
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%cond = select i1 %cmp, i32 %a, i32 %b
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%add = add i32 %cond, 1
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%cmp18 = icmp eq i32 %add, 0
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br i1 %cmp18, label %for.cond.cleanup, label %for.body.preheader
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for.body.preheader: ; preds = %entry
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br label %for.body
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for.cond.cleanup.loopexit: ; preds = %for.body
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br label %for.cond.cleanup
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for.cond.cleanup: ; preds = %for.cond.cleanup.loopexit, %entry
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ret i32 0
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for.body: ; preds = %for.body.preheader, %for.body
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%i.09 = phi i32 [ %inc, %for.body ], [ 0, %for.body.preheader ]
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%arrayidx = getelementptr inbounds i32, i32* %c, i32 %i.09
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store i32 %i.09, i32* %arrayidx, align 4
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%inc = add nuw i32 %i.09, 1
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%cmp1 = icmp ult i32 %inc, %add
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br i1 %cmp1, label %for.body, label %for.cond.cleanup.loopexit
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}
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; Overflow may happen for the multiply expression n * 3, verify that trip
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; multiple is set to 1 if NUW/NSW are not set.
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;
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; __attribute__((noinline)) void a(unsigned n) {
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; #pragma unroll(3)
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; for (unsigned i = 0; i != n * 3; ++i)
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; printf("TEST%u\n", i);
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; }
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; int main() { a(2863311531U); }
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;
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; CHECK: Loop %for.body: Trip multiple is 1
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@.str2 = private unnamed_addr constant [8 x i8] c"TEST%u\0A\00", align 1
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define void @foo2(i32 %n) {
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entry:
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%mul = mul i32 %n, 3
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%cmp4 = icmp eq i32 %mul, 0
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br i1 %cmp4, label %for.cond.cleanup, label %for.body.preheader
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for.body.preheader: ; preds = %entry
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br label %for.body
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for.cond.cleanup.loopexit: ; preds = %for.body
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br label %for.cond.cleanup
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for.cond.cleanup: ; preds = %for.cond.cleanup.loopexit, %entry
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ret void
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for.body: ; preds = %for.body.preheader, %for.body
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%i.05 = phi i32 [ %inc, %for.body ], [ 0, %for.body.preheader ]
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%call = tail call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([8 x i8], [8 x i8]* @.str2, i32 0, i32 0), i32 %i.05)
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%inc = add nuw i32 %i.05, 1
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%cmp = icmp eq i32 %inc, %mul
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br i1 %cmp, label %for.cond.cleanup.loopexit, label %for.body
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}
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declare i32 @printf(i8* nocapture readonly, ...)
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; If we couldn't prove no overflow for the multiply expression 24 * n,
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; returns the greatest power of 2 divisor. If overflows happens
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; the trip count is still divisible by the greatest power of 2 divisor.
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;
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; CHECK: Loop %l3: Trip multiple is 8
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declare void @f()
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define i32 @foo3(i32 %n) {
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entry:
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%loop_ctl = mul i32 %n, 24
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br label %l3
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l3:
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%x.0 = phi i32 [ 0, %entry ], [ %inc, %l3 ]
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call void @f()
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%inc = add i32 %x.0, 1
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%exitcond = icmp eq i32 %inc, %loop_ctl
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br i1 %exitcond, label %exit, label %l3
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exit:
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ret i32 0
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}
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; If the trip count is a constant, verify that we obtained the trip
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; count itself. For huge trip counts, or zero, we return 1.
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;
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; CHECK: Loop %l3: Trip multiple is 3
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define i32 @foo4(i32 %n) {
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entry:
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br label %l3
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l3:
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%x.0 = phi i32 [ 0, %entry ], [ %inc, %l3 ]
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call void @f()
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%inc = add i32 %x.0, 1
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%exitcond = icmp eq i32 %inc, 3
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br i1 %exitcond, label %exit, label %l3
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exit:
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ret i32 0
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}
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