429 lines
11 KiB
LLVM
429 lines
11 KiB
LLVM
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; RUN: opt < %s -loop-deletion -verify-dom-info --pass-remarks-output=%t --pass-remarks-filter=loop-delete -S | FileCheck %s
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; RUN: cat %t | FileCheck %s --check-prefix=REMARKS
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; Checking that we can delete loops that are never executed.
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; We do not change the constant conditional branch statement (where the not-taken target
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; is the loop) to an unconditional one.
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; delete the infinite loop because it is never executed.
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define void @test1(i64 %n, i64 %m) nounwind {
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; CHECK-LABEL: test1
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; CHECK-LABEL: entry:
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; CHECK-NEXT: br i1 true, label %return, label %bb.preheader
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; CHECK-NOT: bb:
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; REMARKS-LABEL: Function: test1
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; REMARKS: Loop deleted because it never executes
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entry:
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br i1 true, label %return, label %bb
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bb:
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%x.0 = phi i64 [ 0, %entry ], [ %t0, %bb ]
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%t0 = add i64 %x.0, 1
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%t1 = icmp slt i64 %x.0, %n
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%t3 = icmp sgt i64 %x.0, %m
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%t4 = and i1 %t1, %t3
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br i1 true, label %bb, label %return
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return:
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ret void
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}
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; FIXME: We can delete this infinite loop. Currently we do not,
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; because the infinite loop has no exit block.
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define void @test2(i64 %n, i64 %m) nounwind {
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; CHECK-LABEL: test2
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; CHECK-LABEL: entry:
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; CHECK-NEXT: br i1 true, label %return, label %bb.preheader
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; CHECK-LABEL: bb:
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; CHECK: br label %bb
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entry:
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br i1 true, label %return, label %bb
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bb:
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%x.0 = phi i64 [ 0, %entry ], [ %t0, %bb ]
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%t0 = add i64 %x.0, 1
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%t1 = icmp slt i64 %x.0, %n
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%t3 = icmp sgt i64 %x.0, %m
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%t4 = and i1 %t1, %t3
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br label %bb
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return:
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ret void
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}
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; There are multiple exiting blocks and a single exit block.
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; Since it is a never executed loop, we do not care about the values
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; from different exiting paths and we can
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; delete the loop.
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define i64 @test3(i64 %n, i64 %m, i64 %maybe_zero) nounwind {
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; CHECK-NOT: bb:
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; CHECK-NOT: bb2:
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; CHECK-NOT: bb3:
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; CHECK-LABEL: return.loopexit:
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; CHECK-NEXT: %x.lcssa.ph = phi i64 [ undef, %bb.preheader ]
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; CHECK-NEXT: br label %return
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; CHECK-LABEL: return:
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; CHECK-NEXT: %x.lcssa = phi i64 [ 20, %entry ], [ %x.lcssa.ph, %return.loopexit ]
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; CHECK-NEXT: ret i64 %x.lcssa
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; REMARKS-LABEL: Function: test3
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; REMARKS: Loop deleted because it never executes
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entry:
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br i1 false, label %bb, label %return
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bb:
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%x.0 = phi i64 [ 0, %entry ], [ %t0, %bb3 ]
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%t0 = add i64 %x.0, 1
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%t1 = icmp slt i64 %x.0, %n
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br i1 %t1, label %bb2, label %return
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bb2:
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%t2 = icmp slt i64 %x.0, %m
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%unused1 = udiv i64 42, %maybe_zero
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br i1 %t2, label %bb3, label %return
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bb3:
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%t3 = icmp slt i64 %x.0, %m
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%unused2 = sdiv i64 42, %maybe_zero
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br i1 %t3, label %bb, label %return
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return:
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; the only valid value fo x.lcssa is 20.
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%x.lcssa = phi i64 [ 12, %bb ], [ 14, %bb2 ], [ 16, %bb3 ], [20, %entry ]
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ret i64 %x.lcssa
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}
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; Cannot delete the loop, since it may be executed at runtime.
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define void @test4(i64 %n, i64 %m, i1 %cond) {
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; CHECK-LABEL: test4
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; CHECK-LABEL: bb:
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entry:
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br i1 %cond, label %looppred1, label %looppred2
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looppred1:
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br i1 true, label %return, label %bb
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looppred2:
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br i1 false, label %return, label %bb
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bb:
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%x.0 = phi i64 [ 0, %looppred1 ], [ 1, %looppred2 ], [ %t0, %bb ]
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%t0 = add i64 %x.0, 1
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%t1 = icmp slt i64 %x.0, %n
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%t3 = icmp sgt i64 %x.0, %m
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%t4 = and i1 %t1, %t3
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br i1 true, label %bb, label %return
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return:
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ret void
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}
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; multiple constant conditional branches with loop not-taken in all cases.
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define void @test5(i64 %n, i64 %m, i1 %cond) nounwind {
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; CHECK-LABEL: test5
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; CHECK-LABEL: looppred1:
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; CHECK-NEXT: br i1 true, label %return, label %bb.preheader
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; CHECK-LABEL: looppred2:
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; CHECK-NEXT: br i1 true, label %return, label %bb.preheader
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; CHECK-NOT: bb:
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; REMARKS-LABEL: Function: test5
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; REMARKS: Loop deleted because it never executes
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entry:
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br i1 %cond, label %looppred1, label %looppred2
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looppred1:
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br i1 true, label %return, label %bb
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looppred2:
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br i1 true, label %return, label %bb
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bb:
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%x.0 = phi i64 [ 0, %looppred1 ], [ 1, %looppred2 ], [ %t0, %bb ]
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%t0 = add i64 %x.0, 1
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%t1 = icmp slt i64 %x.0, %n
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%t3 = icmp sgt i64 %x.0, %m
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%t4 = and i1 %t1, %t3
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br i1 true, label %bb, label %return
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return:
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ret void
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}
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; Don't delete this infinite loop because the loop
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; is executable at runtime.
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define void @test6(i64 %n, i64 %m) nounwind {
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; CHECK-LABEL: test6
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; CHECK-LABEL: entry:
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; CHECK-NEXT: br i1 true, label %bb.preheader, label %bb.preheader
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; CHECK: bb:
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entry:
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br i1 true, label %bb, label %bb
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bb:
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%x.0 = phi i64 [ 0, %entry ], [ 0, %entry ], [ %t0, %bb ]
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%t0 = add i64 %x.0, 1
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%t1 = icmp slt i64 %x.0, %n
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%t3 = icmp sgt i64 %x.0, %m
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%t4 = and i1 %t1, %t3
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br i1 true, label %bb, label %return
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return:
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ret void
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}
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declare i64 @foo(i64)
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; The loop L2 is never executed and is a subloop, with an
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; exit block that branches back to parent loop.
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; Here we can delete loop L2, while L1 still exists.
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define i64 @test7(i64 %n) {
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; CHECK-LABEL: test7
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; CHECK-LABEL: L1:
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; CHECK: br i1 true, label %L1Latch, label %L2.preheader
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; CHECK-LABEL: L2.preheader:
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; CHECK-NEXT: br label %L1Latch.loopexit
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; CHECK-LABEL: L1Latch.loopexit:
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; CHECK: br label %L1Latch
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; CHECK-LABEL: L1Latch:
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; CHECK-NEXT: %y = phi i64 [ %y.next, %L1 ], [ %y.L2.lcssa, %L1Latch.loopexit ]
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; CHECK: br i1 %cond2, label %exit, label %L1
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; REMARKS-LABEL: Function: test7
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; REMARKS: Loop deleted because it never executes
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entry:
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br label %L1
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L1:
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%y.next = phi i64 [ 0, %entry ], [ %y.add, %L1Latch ]
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br i1 true, label %L1Latch, label %L2
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L2:
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%x = phi i64 [ 0, %L1 ], [ %x.next, %L2 ]
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%x.next = add i64 %x, 1
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%y.L2 = call i64 @foo(i64 %x.next)
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%cond = icmp slt i64 %x.next, %n
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br i1 %cond, label %L2, label %L1Latch
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L1Latch:
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%y = phi i64 [ %y.next, %L1 ], [ %y.L2, %L2 ]
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%y.add = add i64 %y, %n
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%cond2 = icmp eq i64 %y.add, 42
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br i1 %cond2, label %exit, label %L1
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exit:
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ret i64 %y.add
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}
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; Show recursive deletion of loops. Since we start with subloops and progress outward
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; to parent loop, we first delete the loop L2. Now loop L1 becomes a non-loop since it's backedge
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; from L2's preheader to L1's exit block is never taken. So, L1 gets deleted as well.
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define void @test8(i64 %n) {
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; CHECK-LABEL: test8
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; CHECK-LABEL: entry:
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; CHECK-NEXT: br label %exit
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; CHECK-LABEL: exit:
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; CHECK-NEXT: ret void
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; REMARKS-LABEL: Function: test8
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; REMARKS: Loop deleted because it never executes
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entry:
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br label %L1
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L1:
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br i1 true, label %exit, label %L2
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L2:
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%x = phi i64 [ 0, %L1 ], [ %x.next, %L2 ]
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%x.next = add i64 %x, 1
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%y.L2 = call i64 @foo(i64 %x.next)
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%cond = icmp slt i64 %x.next, %n
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br i1 %cond, label %L2, label %L1
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exit:
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ret void
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}
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; Delete a loop (L2) which has subloop (L3).
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; Here we delete loop L2, but leave L3 as is.
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define void @test9(i64 %n) {
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; CHECK-LABEL: test9
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; CHECK-LABEL: entry:
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; CHECK-NEXT: br label %exit
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; CHECK-LABEL: exit:
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; CHECK-NEXT: ret void
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; REMARKS-LABEL: Function: test9
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; REMARKS: Loop deleted because it never executes
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entry:
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br label %L1
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L1:
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br i1 true, label %exit, label %L2
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L2:
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%x = phi i64 [ 0, %L1 ], [ %x.next, %L2 ]
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%x.next = add i64 %x, 1
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%y.L2 = call i64 @foo(i64 %x.next)
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%cond = icmp slt i64 %x.next, %n
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br i1 %cond, label %L2, label %L3
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L3:
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%cond2 = icmp slt i64 %y.L2, %n
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br i1 %cond2, label %L3, label %L1
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exit:
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ret void
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}
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; We cannot delete L3 because of call within it.
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; Since L3 is not deleted, and entirely contained within L2, L2 is also not
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; deleted.
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define void @test10(i64 %n) {
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; CHECK-LABEL: test10
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; CHECK-LABEL: entry:
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; CHECK-NEXT: br label %exit
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; CHECK-LABEL: exit:
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; CHECK-NEXT: ret void
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entry:
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br label %L1
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L1:
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br i1 true, label %exit, label %L2
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L2:
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%x = phi i64 [ 0, %L1 ], [ %x.next, %L3 ]
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%x.next = add i64 %x, 1
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%y.L2 = call i64 @foo(i64 %x.next)
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%cond = icmp slt i64 %x.next, %n
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br i1 %cond, label %L1, label %L3
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L3:
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%y.L3 = phi i64 [ %y.L2, %L2 ], [ %y.L3.next, %L3 ]
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%y.L3.next = add i64 %y.L3, 1
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%dummy = call i64 @foo(i64 %y.L3.next)
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%cond2 = icmp slt i64 %y.L3, %n
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br i1 %cond2, label %L3, label %L2
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exit:
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ret void
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}
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; same as test10, but L3 does not contain call.
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; So, in the first iteration, all statements of L3 are made invariant, and L3 is
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; deleted.
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; In the next iteration, since L2 is never executed and has no subloops, we delete
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; L2 as well. Finally, the outermost loop L1 is deleted.
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define void @test11(i64 %n) {
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; CHECK-LABEL: test11
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; CHECK-LABEL: entry:
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; CHECK-NEXT: br label %exit
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; CHECK-LABEL: exit:
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; CHECK-NEXT: ret void
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; REMARKS-LABEL: Function: test11
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; REMARKS: Loop deleted because it is invariant
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; REMARKS-LABEL: Function: test11
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; REMARKS: Loop deleted because it never executes
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; REMARKS-LABEL: Function: test11
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; REMARKS: Loop deleted because it is invariant
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entry:
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br label %L1
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L1:
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br i1 true, label %exit, label %L2
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L2:
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%x = phi i64 [ 0, %L1 ], [ %x.next, %L3 ]
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%x.next = add i64 %x, 1
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%y.L2 = call i64 @foo(i64 %x.next)
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%cond = icmp slt i64 %x.next, %n
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br i1 %cond, label %L1, label %L3
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L3:
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%y.L3 = phi i64 [ %y.L2, %L2 ], [ %y.L3.next, %L3 ]
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%y.L3.next = add i64 %y.L3, 1
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%cond2 = icmp slt i64 %y.L3, %n
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br i1 %cond2, label %L3, label %L2
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exit:
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|
ret void
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
; 2 edges from a single exiting block to the exit block.
|
||
|
|
define i64 @test12(i64 %n){
|
||
|
|
;CHECK-LABEL: @test12
|
||
|
|
; CHECK-NOT: L1:
|
||
|
|
; CHECK-NOT: L1Latch:
|
||
|
|
; CHECK-LABEL: L1.preheader:
|
||
|
|
; CHECK-NEXT: br label %exit
|
||
|
|
; CHECK-LABEL: exit:
|
||
|
|
; CHECK-NEXT: %y.phi = phi i64 [ undef, %L1.preheader ]
|
||
|
|
; CHECK-NEXT: ret i64 %y.phi
|
||
|
|
; REMARKS-LABEL: Function: test12
|
||
|
|
; REMARKS: Loop deleted because it never executes
|
||
|
|
|
||
|
|
entry:
|
||
|
|
br i1 true, label %exit1, label %L1
|
||
|
|
|
||
|
|
exit1:
|
||
|
|
ret i64 42
|
||
|
|
|
||
|
|
L1: ; preds = %L1Latch, %entry
|
||
|
|
%y.next = phi i64 [ 0, %entry ], [ %y.add, %L1Latch ]
|
||
|
|
br i1 true, label %L1Latch, label %exit
|
||
|
|
|
||
|
|
L1Latch: ; preds = %L1
|
||
|
|
%y = phi i64 [ %y.next, %L1 ]
|
||
|
|
%y.add = add i64 %y, %n
|
||
|
|
%cond2 = icmp eq i64 %y.add, 42
|
||
|
|
switch i64 %n, label %L1 [
|
||
|
|
i64 10, label %exit
|
||
|
|
i64 20, label %exit
|
||
|
|
]
|
||
|
|
|
||
|
|
exit: ; preds = %L1Latch, %L1Latch
|
||
|
|
%y.phi = phi i64 [ 10, %L1Latch ], [ 10, %L1Latch ], [ %y.next, %L1]
|
||
|
|
ret i64 %y.phi
|
||
|
|
}
|
||
|
|
|
||
|
|
; multiple edges to exit block from the same exiting blocks
|
||
|
|
define i64 @test13(i64 %n) {
|
||
|
|
; CHECK-LABEL: @test13
|
||
|
|
; CHECK-NOT: L1:
|
||
|
|
; CHECK-NOT: L1Latch:
|
||
|
|
; CHECK-LABEL: L1.preheader:
|
||
|
|
; CHECK-NEXT: br label %exit
|
||
|
|
; CHECK-LABEL: exit:
|
||
|
|
; CHECK-NEXT: %y.phi = phi i64 [ undef, %L1.preheader ]
|
||
|
|
; CHECK-NEXT: ret i64 %y.phi
|
||
|
|
; REMARKS-LABEL: Function: test13
|
||
|
|
; REMARKS: Loop deleted because it never executes
|
||
|
|
|
||
|
|
entry:
|
||
|
|
br i1 true, label %exit1, label %L1
|
||
|
|
|
||
|
|
exit1:
|
||
|
|
ret i64 42
|
||
|
|
|
||
|
|
L1: ; preds = %L1Latch, %entry
|
||
|
|
%y.next = phi i64 [ 0, %entry ], [ %y.add, %L1Latch ]
|
||
|
|
br i1 true, label %L1Block, label %exit
|
||
|
|
|
||
|
|
L1Block: ; preds = %L1
|
||
|
|
%y = phi i64 [ %y.next, %L1 ]
|
||
|
|
%y.add = add i64 %y, %n
|
||
|
|
%cond2 = icmp eq i64 %y.add, 42
|
||
|
|
switch i64 %n, label %L1Latch [
|
||
|
|
i64 10, label %exit
|
||
|
|
i64 20, label %exit
|
||
|
|
]
|
||
|
|
|
||
|
|
L1Latch:
|
||
|
|
switch i64 %n, label %L1 [
|
||
|
|
i64 30, label %exit
|
||
|
|
i64 40, label %exit
|
||
|
|
]
|
||
|
|
|
||
|
|
exit: ; preds = %L1Block, %L1, %L1Latch
|
||
|
|
%y.phi = phi i64 [ 10, %L1Block ], [ 10, %L1Block ], [ %y.next, %L1 ], [ 30, %L1Latch ], [ 30, %L1Latch ]
|
||
|
|
ret i64 %y.phi
|
||
|
|
}
|