[all-commits] [llvm/llvm-project] 25d9fd: [SCCP] Skip computing intrinsics if one of its arg...

[luxufan via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 25d9fde22e609f8637f720220810429745707b76
      https://github.com/llvm/llvm-project/commit/25d9fde22e609f8637f720220810429745707b76
  Author: luxufan <luxufan at iscas.ac.cn>
  Date:   2023-06-10 (Sat, 10 Jun 2023)

  Changed paths:
    M llvm/lib/Transforms/Utils/SCCPSolver.cpp
    M llvm/test/Transforms/SCCP/intrinsics.ll

  Log Message:
  -----------
  [SCCP] Skip computing intrinsics if one of its args is unknownOrUndef

For constant range supported intrinsics, we got consantrange from args
no matter if they are unknown or undef. And the constant range computed
from unknown or undef value state is full range.

I think compute with full constant range is harmful since although we
can do mergeIn after these args value state are changed, the merge
operation of two constant ranges is union.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D152499