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416 lines
12 KiB
416 lines
12 KiB
; RUN: opt -analyze -scalar-evolution -S < %s | FileCheck %s
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; Every combination of
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; - starting at 0, 1, or %x
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; - steping by 1 or 2
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; - stopping at %n or %n*2
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; - using nsw, or not
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; Some of these represent missed opportunities.
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; CHECK: Determining loop execution counts for: @foo
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; CHECK: Loop %loop: backedge-taken count is (-1 + %n)
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; CHECK: Loop %loop: max backedge-taken count is 6
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define void @foo(i4 %n) {
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entry:
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%s = icmp sgt i4 %n, 0
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br i1 %s, label %loop, label %exit
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loop:
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%i = phi i4 [ 0, %entry ], [ %i.next, %loop ]
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%i.next = add i4 %i, 1
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%t = icmp slt i4 %i.next, %n
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br i1 %t, label %loop, label %exit
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exit:
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ret void
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}
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; CHECK: Determining loop execution counts for: @step2
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; CHECK: Loop %loop: Unpredictable backedge-taken count.
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; CHECK: Loop %loop: Unpredictable max backedge-taken count.
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define void @step2(i4 %n) {
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entry:
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%s = icmp sgt i4 %n, 0
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br i1 %s, label %loop, label %exit
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loop:
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%i = phi i4 [ 0, %entry ], [ %i.next, %loop ]
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%i.next = add i4 %i, 2
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%t = icmp slt i4 %i.next, %n
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br i1 %t, label %loop, label %exit
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exit:
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ret void
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}
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; CHECK: Determining loop execution counts for: @start1
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; CHECK: Loop %loop: backedge-taken count is (-2 + (2 smax %n))
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; CHECK: Loop %loop: max backedge-taken count is 5
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define void @start1(i4 %n) {
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entry:
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%s = icmp sgt i4 %n, 0
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br i1 %s, label %loop, label %exit
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loop:
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%i = phi i4 [ 1, %entry ], [ %i.next, %loop ]
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%i.next = add i4 %i, 1
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%t = icmp slt i4 %i.next, %n
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br i1 %t, label %loop, label %exit
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exit:
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ret void
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}
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; CHECK: Determining loop execution counts for: @start1_step2
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; CHECK: Loop %loop: Unpredictable backedge-taken count.
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; CHECK: Loop %loop: Unpredictable max backedge-taken count.
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define void @start1_step2(i4 %n) {
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entry:
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%s = icmp sgt i4 %n, 0
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br i1 %s, label %loop, label %exit
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loop:
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%i = phi i4 [ 1, %entry ], [ %i.next, %loop ]
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%i.next = add i4 %i, 2
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%t = icmp slt i4 %i.next, %n
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br i1 %t, label %loop, label %exit
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exit:
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ret void
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}
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; CHECK: Determining loop execution counts for: @startx
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; CHECK: Loop %loop: backedge-taken count is (-1 + (-1 * %x) + ((1 + %x) smax %n))
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; CHECK: Loop %loop: max backedge-taken count is -1
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define void @startx(i4 %n, i4 %x) {
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entry:
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%s = icmp sgt i4 %n, 0
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br i1 %s, label %loop, label %exit
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loop:
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%i = phi i4 [ %x, %entry ], [ %i.next, %loop ]
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%i.next = add i4 %i, 1
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%t = icmp slt i4 %i.next, %n
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br i1 %t, label %loop, label %exit
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exit:
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ret void
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}
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; CHECK: Determining loop execution counts for: @startx_step2
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; CHECK: Loop %loop: Unpredictable backedge-taken count.
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; CHECK: Loop %loop: Unpredictable max backedge-taken count.
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define void @startx_step2(i4 %n, i4 %x) {
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entry:
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%s = icmp sgt i4 %n, 0
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br i1 %s, label %loop, label %exit
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loop:
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%i = phi i4 [ %x, %entry ], [ %i.next, %loop ]
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%i.next = add i4 %i, 2
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%t = icmp slt i4 %i.next, %n
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br i1 %t, label %loop, label %exit
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exit:
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ret void
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}
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; CHECK: Determining loop execution counts for: @nsw
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; CHECK: Loop %loop: backedge-taken count is (-1 + %n)
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; CHECK: Loop %loop: max backedge-taken count is 6
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define void @nsw(i4 %n) {
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entry:
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%s = icmp sgt i4 %n, 0
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br i1 %s, label %loop, label %exit
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loop:
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%i = phi i4 [ 0, %entry ], [ %i.next, %loop ]
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%i.next = add nsw i4 %i, 1
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%t = icmp slt i4 %i.next, %n
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br i1 %t, label %loop, label %exit
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exit:
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ret void
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}
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; If %n is INT4_MAX, %i.next will wrap. The nsw bit says that the
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; result is undefined. Therefore, after the loop's second iteration,
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; we are free to assume that the loop exits. This is valid because:
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; (a) %i.next is a poison value after the second iteration, which can
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; also be considered an undef value.
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; (b) the return instruction enacts a side effect that is control
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; dependent on the poison value.
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;
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; CHECK-LABEL: nsw_step2
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; CHECK: Determining loop execution counts for: @nsw_step2
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; CHECK: Loop %loop: backedge-taken count is ((-1 + %n) /u 2)
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; CHECK: Loop %loop: max backedge-taken count is 2
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define void @nsw_step2(i4 %n) {
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entry:
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%s = icmp sgt i4 %n, 0
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br i1 %s, label %loop, label %exit
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loop:
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%i = phi i4 [ 0, %entry ], [ %i.next, %loop ]
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%i.next = add nsw i4 %i, 2
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%t = icmp slt i4 %i.next, %n
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br i1 %t, label %loop, label %exit
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exit:
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ret void
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}
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; CHECK-LABEL: nsw_start1
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; CHECK: Determining loop execution counts for: @nsw_start1
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; CHECK: Loop %loop: backedge-taken count is (-2 + (2 smax %n))
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; CHECK: Loop %loop: max backedge-taken count is 5
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define void @nsw_start1(i4 %n) {
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entry:
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%s = icmp sgt i4 %n, 0
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br i1 %s, label %loop, label %exit
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loop:
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%i = phi i4 [ 1, %entry ], [ %i.next, %loop ]
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%i.next = add nsw i4 %i, 1
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%t = icmp slt i4 %i.next, %n
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br i1 %t, label %loop, label %exit
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exit:
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ret void
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}
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; CHECK: Determining loop execution counts for: @nsw_start1_step2
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; CHECK: Loop %loop: backedge-taken count is ((-2 + (3 smax %n)) /u 2)
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; CHECK: Loop %loop: max backedge-taken count is 2
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define void @nsw_start1_step2(i4 %n) {
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entry:
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%s = icmp sgt i4 %n, 0
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br i1 %s, label %loop, label %exit
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loop:
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%i = phi i4 [ 1, %entry ], [ %i.next, %loop ]
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%i.next = add nsw i4 %i, 2
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%t = icmp slt i4 %i.next, %n
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br i1 %t, label %loop, label %exit
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exit:
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ret void
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}
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; CHECK: Determining loop execution counts for: @nsw_startx
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; CHECK: Loop %loop: backedge-taken count is (-1 + (-1 * %x) + ((1 + %x) smax %n))
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; CHECK: Loop %loop: max backedge-taken count is -1
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define void @nsw_startx(i4 %n, i4 %x) {
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entry:
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%s = icmp sgt i4 %n, 0
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br i1 %s, label %loop, label %exit
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loop:
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%i = phi i4 [ %x, %entry ], [ %i.next, %loop ]
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%i.next = add nsw i4 %i, 1
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%t = icmp slt i4 %i.next, %n
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br i1 %t, label %loop, label %exit
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exit:
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ret void
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}
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; CHECK: Determining loop execution counts for: @nsw_startx_step2
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; CHECK: Loop %loop: backedge-taken count is ((-1 + (-1 * %x) + ((2 + %x) smax %n)) /u 2)
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; CHECK: Loop %loop: max backedge-taken count is 7
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define void @nsw_startx_step2(i4 %n, i4 %x) {
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entry:
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%s = icmp sgt i4 %n, 0
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br i1 %s, label %loop, label %exit
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loop:
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%i = phi i4 [ %x, %entry ], [ %i.next, %loop ]
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%i.next = add nsw i4 %i, 2
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%t = icmp slt i4 %i.next, %n
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br i1 %t, label %loop, label %exit
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exit:
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ret void
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}
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; CHECK: Determining loop execution counts for: @even
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; CHECK: Loop %loop: backedge-taken count is (-1 + (2 * %n))
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; CHECK: Loop %loop: max backedge-taken count is 5
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define void @even(i4 %n) {
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entry:
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%m = shl i4 %n, 1
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%s = icmp sgt i4 %m, 0
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br i1 %s, label %loop, label %exit
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loop:
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%i = phi i4 [ 0, %entry ], [ %i.next, %loop ]
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%i.next = add i4 %i, 1
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%t = icmp slt i4 %i.next, %m
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br i1 %t, label %loop, label %exit
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exit:
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ret void
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}
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; CHECK: Determining loop execution counts for: @even_step2
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; CHECK: Loop %loop: backedge-taken count is ((-1 + (2 * %n)) /u 2)
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; CHECK: Loop %loop: max backedge-taken count is 2
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define void @even_step2(i4 %n) {
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entry:
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%m = shl i4 %n, 1
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%s = icmp sgt i4 %m, 0
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br i1 %s, label %loop, label %exit
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loop:
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%i = phi i4 [ 0, %entry ], [ %i.next, %loop ]
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%i.next = add i4 %i, 2
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%t = icmp slt i4 %i.next, %m
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br i1 %t, label %loop, label %exit
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exit:
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ret void
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}
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; CHECK: Determining loop execution counts for: @even_start1
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; CHECK: Loop %loop: backedge-taken count is (-2 + (2 smax (2 * %n)))
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; CHECK: Loop %loop: max backedge-taken count is 4
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define void @even_start1(i4 %n) {
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entry:
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%m = shl i4 %n, 1
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%s = icmp sgt i4 %m, 0
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br i1 %s, label %loop, label %exit
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loop:
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%i = phi i4 [ 1, %entry ], [ %i.next, %loop ]
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%i.next = add i4 %i, 1
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%t = icmp slt i4 %i.next, %m
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br i1 %t, label %loop, label %exit
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exit:
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ret void
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}
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; CHECK: Determining loop execution counts for: @even_start1_step2
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; CHECK: Loop %loop: backedge-taken count is ((-2 + (3 smax (2 * %n))) /u 2)
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; CHECK: Loop %loop: max backedge-taken count is 2
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define void @even_start1_step2(i4 %n) {
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entry:
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%m = shl i4 %n, 1
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%s = icmp sgt i4 %m, 0
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br i1 %s, label %loop, label %exit
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loop:
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%i = phi i4 [ 1, %entry ], [ %i.next, %loop ]
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%i.next = add i4 %i, 2
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%t = icmp slt i4 %i.next, %m
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br i1 %t, label %loop, label %exit
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exit:
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ret void
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}
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; CHECK: Determining loop execution counts for: @even_startx
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; CHECK: Loop %loop: backedge-taken count is (-1 + (-1 * %x) + ((1 + %x) smax (2 * %n)))
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; CHECK: Loop %loop: max backedge-taken count is -2
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define void @even_startx(i4 %n, i4 %x) {
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entry:
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%m = shl i4 %n, 1
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%s = icmp sgt i4 %m, 0
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br i1 %s, label %loop, label %exit
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loop:
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%i = phi i4 [ %x, %entry ], [ %i.next, %loop ]
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%i.next = add i4 %i, 1
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%t = icmp slt i4 %i.next, %m
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br i1 %t, label %loop, label %exit
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exit:
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ret void
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}
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; CHECK: Determining loop execution counts for: @even_startx_step2
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; CHECK: Loop %loop: backedge-taken count is ((-1 + (-1 * %x) + ((2 + %x) smax (2 * %n))) /u 2)
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; CHECK: Loop %loop: max backedge-taken count is 7
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define void @even_startx_step2(i4 %n, i4 %x) {
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entry:
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%m = shl i4 %n, 1
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%s = icmp sgt i4 %m, 0
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br i1 %s, label %loop, label %exit
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loop:
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%i = phi i4 [ %x, %entry ], [ %i.next, %loop ]
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%i.next = add i4 %i, 2
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%t = icmp slt i4 %i.next, %m
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br i1 %t, label %loop, label %exit
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exit:
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ret void
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}
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; CHECK: Determining loop execution counts for: @even_nsw
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; CHECK: Loop %loop: backedge-taken count is (-1 + (2 * %n))
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; CHECK: Loop %loop: max backedge-taken count is 5
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define void @even_nsw(i4 %n) {
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entry:
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%m = shl i4 %n, 1
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%s = icmp sgt i4 %m, 0
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br i1 %s, label %loop, label %exit
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loop:
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%i = phi i4 [ 0, %entry ], [ %i.next, %loop ]
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%i.next = add nsw i4 %i, 1
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%t = icmp slt i4 %i.next, %m
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br i1 %t, label %loop, label %exit
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exit:
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ret void
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}
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; CHECK: Determining loop execution counts for: @even_nsw_step2
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; CHECK: Loop %loop: backedge-taken count is ((-1 + (2 * %n)) /u 2)
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; CHECK: Loop %loop: max backedge-taken count is 2
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define void @even_nsw_step2(i4 %n) {
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entry:
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%m = shl i4 %n, 1
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%s = icmp sgt i4 %m, 0
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br i1 %s, label %loop, label %exit
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loop:
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%i = phi i4 [ 0, %entry ], [ %i.next, %loop ]
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%i.next = add nsw i4 %i, 2
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%t = icmp slt i4 %i.next, %m
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br i1 %t, label %loop, label %exit
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exit:
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ret void
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}
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; CHECK: Determining loop execution counts for: @even_nsw_start1
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; CHECK: Loop %loop: backedge-taken count is (-2 + (2 smax (2 * %n)))
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; CHECK: Loop %loop: max backedge-taken count is 4
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define void @even_nsw_start1(i4 %n) {
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entry:
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%m = shl i4 %n, 1
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%s = icmp sgt i4 %m, 0
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br i1 %s, label %loop, label %exit
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loop:
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%i = phi i4 [ 1, %entry ], [ %i.next, %loop ]
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%i.next = add nsw i4 %i, 1
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%t = icmp slt i4 %i.next, %m
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br i1 %t, label %loop, label %exit
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exit:
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ret void
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}
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; CHECK: Determining loop execution counts for: @even_nsw_start1_step2
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; CHECK: Loop %loop: backedge-taken count is ((-2 + (3 smax (2 * %n))) /u 2)
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; CHECK: Loop %loop: max backedge-taken count is 2
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define void @even_nsw_start1_step2(i4 %n) {
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entry:
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%m = shl i4 %n, 1
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%s = icmp sgt i4 %m, 0
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br i1 %s, label %loop, label %exit
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loop:
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%i = phi i4 [ 1, %entry ], [ %i.next, %loop ]
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%i.next = add nsw i4 %i, 2
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%t = icmp slt i4 %i.next, %m
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br i1 %t, label %loop, label %exit
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exit:
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ret void
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}
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; CHECK: Determining loop execution counts for: @even_nsw_startx
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; CHECK: Loop %loop: backedge-taken count is (-1 + (-1 * %x) + ((1 + %x) smax (2 * %n)))
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; CHECK: Loop %loop: max backedge-taken count is -2
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define void @even_nsw_startx(i4 %n, i4 %x) {
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entry:
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%m = shl i4 %n, 1
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%s = icmp sgt i4 %m, 0
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br i1 %s, label %loop, label %exit
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loop:
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%i = phi i4 [ %x, %entry ], [ %i.next, %loop ]
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%i.next = add nsw i4 %i, 1
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%t = icmp slt i4 %i.next, %m
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br i1 %t, label %loop, label %exit
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exit:
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ret void
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}
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; CHECK: Determining loop execution counts for: @even_nsw_startx_step2
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; CHECK: Loop %loop: backedge-taken count is ((-1 + (-1 * %x) + ((2 + %x) smax (2 * %n))) /u 2)
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; CHECK: Loop %loop: max backedge-taken count is 7
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define void @even_nsw_startx_step2(i4 %n, i4 %x) {
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entry:
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%m = shl i4 %n, 1
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%s = icmp sgt i4 %m, 0
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br i1 %s, label %loop, label %exit
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loop:
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%i = phi i4 [ %x, %entry ], [ %i.next, %loop ]
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%i.next = add nsw i4 %i, 2
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%t = icmp slt i4 %i.next, %m
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br i1 %t, label %loop, label %exit
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exit:
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ret void
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}
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