llvm-project/llvm/test/Analysis/ScalarEvolution/max-be-count-not-constant.ll

27 lines
856 B
LLVM

; RUN: opt < %s -analyze -scalar-evolution | FileCheck %s
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
; Previously in this case the max backedge count would be computed as 1/0, which
; is correct but undesirable. It would also not fold as a constant, tripping
; asserts in SCEV.
define void @pluto(i32 %arg) {
; CHECK-LABEL: Classifying expressions for: @pluto
; CHECK: Loop %bb2: max backedge-taken count is 2
bb:
%tmp = ashr i32 %arg, 31
%tmp1 = add nsw i32 %tmp, 2
br label %bb2
bb2: ; preds = %bb2, %bb
%tmp3 = phi i32 [ 0, %bb ], [ %tmp4, %bb2 ]
%tmp4 = add nuw nsw i32 %tmp1, %tmp3
%tmp5 = icmp ult i32 %tmp4, 2
br i1 %tmp5, label %bb2, label %bb6
bb6: ; preds = %bb2
ret void
}