Wenju He 79bf8c0331
[InstCombine] Fold select(X >s 0, 0, -X) | smax(X, 0) to abs(X) (#165200)
The IR pattern is compiled from OpenCL code:
  __builtin_astype(x > (uchar2)(0) ? x : -x, uchar2);
where smax is created by foldSelectInstWithICmp + canonicalizeSPF.

smax could also come from direct elementwise max call:
  int c = b > (int)(0) ? (int)(0) : -b;
  int d = __builtin_elementwise_max(b, (int)(0));
  *a = c | d;

https://alive2.llvm.org/ce/z/2-brvr
https://alive2.llvm.org/ce/z/Dowjzk
https://alive2.llvm.org/ce/z/kathwZ

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Co-authored-by: Yingwei Zheng <dtcxzyw@qq.com>
Co-authored-by: Matt Arsenault <arsenm2@gmail.com>
2025-11-03 07:38:21 +08:00
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