[all-commits] [llvm/llvm-project] 74a98f: Revert "[x86] combineMul - use computeKnownBits di...

[Hans via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 74a98fdbc4435a9f8cdf9ea6d1d9a0396921d3d6
      https://github.com/llvm/llvm-project/commit/74a98fdbc4435a9f8cdf9ea6d1d9a0396921d3d6
  Author: Hans Wennborg <hans at chromium.org>
  Date:   2024-10-07 (Mon, 07 Oct 2024)

  Changed paths:
    M llvm/lib/Target/X86/X86ISelLowering.cpp
    M llvm/test/CodeGen/X86/combine-add.ll
    M llvm/test/CodeGen/X86/vector-mul.ll

  Log Message:
  -----------
  Revert "[x86] combineMul - use computeKnownBits directly to find MUL_IMM constant splat."

> As we're after a constant splat value we can avoid all the complexities of trying to recreate the correct constant via getTargetConstantFromNode.

This caused builds to fail with an assertion:
X86ISelLowering.cpp:48569
Assertion `C.getZExtValue() != 0 && C.getZExtValue() != maxUIntN(VT.getScalarSizeInBits())
&& "Both cases that could cause potential overflows should have " "already been handled."

See https://github.com/llvm/llvm-project/issues/111325

This reverts commit 1bc87c9f3cb20a51191f522bf4d69338ad6bb4e6.



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