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0a4606b261
The range of SCEVUnknown Phi which merges values `X1, X2, ..., XN` can be evaluated as `U(Range(X1), Range(X2), ..., Range(XN))`. Reviewed By: sanjoy Differential Revision: https://reviews.llvm.org/D43810 llvm-svn: 326418
55 lines
1.6 KiB
LLVM
55 lines
1.6 KiB
LLVM
; RUN: opt < %s -analyze -scalar-evolution | FileCheck %s
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define void @merge_values_with_ranges(i32 *%a_len_ptr, i32 *%b_len_ptr, i1 %unknown_cond) {
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; CHECK-LABEL: Classifying expressions for: @merge_values_with_ranges
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; CHECK: %len = phi i32 [ %len_a, %if.true ], [ %len_b, %if.false ]
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; CHECK-NEXT: --> %len U: [0,2147483647) S: [0,2147483647)
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entry:
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br i1 %unknown_cond, label %if.true, label %if.false
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if.true:
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%len_a = load i32, i32* %a_len_ptr, !range !0
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br label %merge
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if.false:
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%len_b = load i32, i32* %b_len_ptr, !range !0
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br label %merge
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merge:
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%len = phi i32 [ %len_a, %if.true ], [ %len_b, %if.false ]
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ret void
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}
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define void @merge_values_with_ranges_looped(i32 *%a_len_ptr, i32 *%b_len_ptr) {
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; TODO: We could be much smarter here. So far we just make sure that we do not
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; go into infinite loop analyzing these Phis.
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; CHECK-LABEL: Classifying expressions for: @merge_values_with_ranges_looped
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; CHECK: %p1 = phi i32 [ %len_a, %entry ], [ %p2, %loop ]
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; CHECK-NEXT: --> %p1 U: full-set S: full-set
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; CHECK: %p2 = phi i32 [ %len_b, %entry ], [ %p1, %loop ]
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; CHECK-NEXT: --> %p2 U: full-set S: full-set
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entry:
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%len_a = load i32, i32* %a_len_ptr, !range !0
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%len_b = load i32, i32* %b_len_ptr, !range !0
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br label %loop
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loop:
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%p1 = phi i32 [ %len_a, %entry ], [ %p2, %loop ]
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%p2 = phi i32 [ %len_b, %entry ], [ %p1, %loop ]
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%iv = phi i32 [ 0, %entry ], [ %iv.next, %loop ]
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%iv.next = add i32 %iv, 1
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%loop.cond = icmp slt i32 %iv.next, 100
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br i1 %loop.cond, label %loop, label %exit
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exit:
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ret void
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}
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!0 = !{i32 0, i32 2147483647}
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