File: arm64-AnInfiniteLoopInDAGCombine.ll

package info (click to toggle)
llvm-toolchain-15 1%3A15.0.6-4
  • links: PTS, VCS
  • area: main
  • in suites: bookworm
  • size: 1,554,644 kB
  • sloc: cpp: 5,922,452; ansic: 1,012,136; asm: 674,362; python: 191,568; objc: 73,855; f90: 42,327; lisp: 31,913; pascal: 11,973; javascript: 10,144; sh: 9,421; perl: 7,447; ml: 5,527; awk: 3,523; makefile: 2,520; xml: 885; cs: 573; fortran: 567
file content (23 lines) | stat: -rw-r--r-- 1,050 bytes parent folder | download | duplicates (28) 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
 
; RUN: llc < %s -mtriple=arm64-eabi

; This test case tests an infinite loop bug in DAG combiner.
; It just tries to do the following replacing endlessly:
; (1)  Replacing.3 0x2c509f0: v4i32 = any_extend 0x2c4cd08 [ORD=4]
;      With: 0x2c4d128: v4i32 = sign_extend 0x2c4cd08 [ORD=4]
;
; (2)  Replacing.2 0x2c4d128: v4i32 = sign_extend 0x2c4cd08 [ORD=4]
;      With: 0x2c509f0: v4i32 = any_extend 0x2c4cd08 [ORD=4]
; As we think the (2) optimization from SIGN_EXTEND to ANY_EXTEND is
; an optimization to replace unused bits with undefined bits, we remove
; the (1) optimization (It doesn't make sense to replace undefined bits
; with signed bits).

define <4 x i32> @infiniteLoop(<4 x i32> %in0, <4 x i16> %in1) {
entry:
  %cmp.i = icmp sge <4 x i16> %in1, <i16 32767, i16 32767, i16 -1, i16 -32768>
  %sext.i = sext <4 x i1> %cmp.i to <4 x i32>
  %mul.i = mul <4 x i32> %in0, %sext.i
  %sext = shl <4 x i32> %mul.i, <i32 16, i32 16, i32 16, i32 16>
  %vmovl.i.i = ashr <4 x i32> %sext, <i32 16, i32 16, i32 16, i32 16>
  ret <4 x i32> %vmovl.i.i
}