165 lines
3.8 KiB
LLVM
165 lines
3.8 KiB
LLVM
; RUN: opt -analyze -scalar-evolution < %s | FileCheck %s
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define void @test0(i32 %init) {
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; CHECK-LABEL: Classifying expressions for: @test0
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; CHECK: Loop %loop: max backedge-taken count is 32
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entry:
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br label %loop
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loop:
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%iv = phi i32 [ %init, %entry ], [ %iv.shift, %loop ]
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%iv.shift = lshr i32 %iv, 1
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%exit.cond = icmp eq i32 %iv, 0
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br i1 %exit.cond, label %leave, label %loop
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leave:
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ret void
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}
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define void @test1(i32 %init) {
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; CHECK-LABEL: Classifying expressions for: @test1
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; CHECK: Loop %loop: max backedge-taken count is 32
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entry:
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br label %loop
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loop:
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%iv = phi i32 [ %init, %entry ], [ %iv.shift, %loop ]
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%iv.shift = shl i32 %iv, 1
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%exit.cond = icmp eq i32 %iv, 0
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br i1 %exit.cond, label %leave, label %loop
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leave:
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ret void
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}
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define void @test2(i32 %init) {
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; CHECK-LABEL: Determining loop execution counts for: @test2
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; CHECK: Loop %loop: Unpredictable max backedge-taken count.
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; Unpredictable because %iv could "stabilize" to either -1 or 0,
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; depending on %init.
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entry:
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br label %loop
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loop:
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%iv = phi i32 [ %init, %entry ], [ %iv.shift, %loop ]
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%iv.shift = ashr i32 %iv, 1
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%exit.cond = icmp eq i32 %iv, 0
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br i1 %exit.cond, label %leave, label %loop
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leave:
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ret void
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}
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define void @test3(i32* %init.ptr) {
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; CHECK-LABEL: Determining loop execution counts for: @test3
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; CHECK: Loop %loop: max backedge-taken count is 32
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entry:
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%init = load i32, i32* %init.ptr, !range !0
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br label %loop
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loop:
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%iv = phi i32 [ %init, %entry ], [ %iv.shift, %loop ]
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%iv.shift = ashr i32 %iv, 1
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%exit.cond = icmp eq i32 %iv, 0
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br i1 %exit.cond, label %leave, label %loop
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leave:
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ret void
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}
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define void @test4(i32* %init.ptr) {
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; CHECK-LABEL: Classifying expressions for: @test4
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; CHECK-LABEL: Loop %loop: max backedge-taken count is 32
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entry:
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%init = load i32, i32* %init.ptr, !range !1
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br label %loop
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loop:
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%iv = phi i32 [ %init, %entry ], [ %iv.shift, %loop ]
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%iv.shift = ashr i32 %iv, 1
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%exit.cond = icmp eq i32 %iv, -1
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br i1 %exit.cond, label %leave, label %loop
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leave:
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ret void
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}
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define void @test5(i32* %init.ptr) {
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; CHECK-LABEL: Determining loop execution counts for: @test5
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; CHECK: Loop %loop: Unpredictable max backedge-taken count.
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; %iv will "stabilize" to -1, so this is an infinite loop
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entry:
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%init = load i32, i32* %init.ptr, !range !1
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br label %loop
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loop:
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%iv = phi i32 [ %init, %entry ], [ %iv.shift, %loop ]
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%iv.shift = ashr i32 %iv, 1
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%exit.cond = icmp eq i32 %iv, 0
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br i1 %exit.cond, label %leave, label %loop
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leave:
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ret void
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}
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define void @test6(i32 %init, i32 %shift.amt) {
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; CHECK-LABEL: Determining loop execution counts for: @test6
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; CHECK: Loop %loop: Unpredictable max backedge-taken count.
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; Potentially infinite loop, since %shift.amt could be 0
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entry:
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br label %loop
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loop:
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%iv = phi i32 [ %init, %entry ], [ %iv.shift, %loop ]
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%iv.shift = lshr i32 %iv, %shift.amt
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%exit.cond = icmp eq i32 %iv, 0
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br i1 %exit.cond, label %leave, label %loop
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leave:
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ret void
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}
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define void @test7(i32 %init) {
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; CHECK-LABEL: Classifying expressions for: @test7
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; CHECK: Loop %loop: max backedge-taken count is 32
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entry:
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br label %loop
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loop:
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%iv = phi i32 [ %init, %entry ], [ %iv.shift, %loop ]
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%iv.shift = lshr i32 %iv, 1
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%exit.cond = icmp eq i32 %iv.shift, 0
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br i1 %exit.cond, label %leave, label %loop
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leave:
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ret void
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}
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define void @test8(i32 %init) {
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; CHECK-LABEL: Classifying expressions for: @test8
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; CHECK: Loop %loop: Unpredictable max backedge-taken count.
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; In this test case, %iv.test stabilizes to 127, not -1, so the loop
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; is infinite.
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entry:
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br label %loop
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loop:
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%iv = phi i32 [ %init, %entry ], [ %iv.shift, %loop ]
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%iv.shift = ashr i32 %iv, 1
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%iv.test = lshr i32 %iv, 1
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%exit.cond = icmp eq i32 %iv.test, -1
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br i1 %exit.cond, label %leave, label %loop
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leave:
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ret void
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}
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!0 = !{i32 0, i32 50000}
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!1 = !{i32 -5000, i32 -1}
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