[PATCH] D142546: [ConstraintElimination] Decompose or instruction if the constant operand < 2^known_zero_bits of the first operand.

[Zain Jaffal via Phabricator via llvm-commits]

zjaffal marked 4 inline comments as done.
zjaffal added inline comments.


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Comment at: llvm/test/Transforms/ConstraintElimination/or.ll:534-535
 ; CHECK-NEXT:    [[START_4:%.*]] = or i8 [[START]], 4
 ; CHECK-NEXT:    [[T_4:%.*]] = icmp ule i8 [[START_4]], [[HIGH]]
 ; CHECK-NEXT:    call void @use(i1 [[T_4]])
 ; CHECK-NEXT:    [[START_5:%.*]] = or i8 [[START]], 5
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This transformation should be true
https://alive2.llvm.org/ce/z/xvrMtA

`hasNoCommonBits` doesn't optimise it while the original implementation did


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Comment at: llvm/test/Transforms/ConstraintElimination/or.ll:610-611
 ; CHECK-NEXT:    [[START_4:%.*]] = or i8 [[START]], 4
 ; CHECK-NEXT:    [[F_4:%.*]] = icmp ugt i8 [[START_4]], [[HIGH]]
 ; CHECK-NEXT:    call void @use(i1 [[F_4]])
 ; CHECK-NEXT:    [[START_5:%.*]] = or i8 [[START]], 5
----------------
this check should be false 
https://alive2.llvm.org/ce/z/9-7sJR



Repository:
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CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D142546/new/

https://reviews.llvm.org/D142546