1; RUN: opt -loop-reduce -S < %s | FileCheck %s
2
3target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
4target triple = "x86_64-apple-macosx"
5
6; PR15470: LSR miscompile. The test2 function should return '1'.
7;
8; SCEV expander cannot expand quadratic recurrences outside of the
9; loop. This recurrence depends on %sub.us, so can't be expanded.
10;
11; CHECK-LABEL: @test2
12; CHECK-LABEL: test2.loop:
13; CHECK: %lsr.iv = phi i32 [ %lsr.iv.next, %test2.loop ], [ -16777216, %entry ]
14; CHECK: %lsr.iv.next = add nsw i32 %lsr.iv, 16777216
15;
16; CHECK-LABEL: for.end:
17; CHECK: %sub.cond.us = sub nsw i32 %inc1115.us, %sub.us
18; CHECK: %sext.us = mul i32 %lsr.iv.next, %sub.cond.us
19; CHECK: %f = ashr i32 %sext.us, 24
20; CHECK: ret i32 %f
21define i32 @test2() {
22entry:
23  br label %test2.loop
24
25test2.loop:
26  %inc1115.us = phi i32 [ 0, %entry ], [ %inc11.us, %test2.loop ]
27  %inc11.us = add nsw i32 %inc1115.us, 1
28  %cmp.us = icmp slt i32 %inc11.us, 2
29  br i1 %cmp.us, label %test2.loop, label %for.end
30
31for.end:
32  %tobool.us = icmp eq i32 %inc1115.us, 0
33  %sub.us = select i1 %tobool.us, i32 0, i32 0
34  %mul.us = shl i32 %inc1115.us, 24
35  %sub.cond.us = sub nsw i32 %inc1115.us, %sub.us
36  %sext.us = mul i32 %mul.us, %sub.cond.us
37  %f = ashr i32 %sext.us, 24
38  br label %exit
39
40exit:
41  ret i32 %f
42}
43