Noah Goldstein 2622b2f409 [ValueTracking] Use select condition to help determine if select is non-zero ...

In `select c, x, y` the condition `c` dominates the resulting `x` or
`y` chosen by the `select`. This adds logic to `isKnownNonZero` to try
and use the `icmp` for the `c` condition to see if it implies the
select `x` or `y` are known non-zero.

For example in:
    ```
    %c = icmp ugt i8 %x, %C
    %r = select i1 %c, i8 %x, i8 %y
    ```
    The true arm of select `%x` is non-zero (when "returned" by the
    `select`) because `%c` being true implies `%x` is non-zero.

Alive2 Links (with `x {pred} C`):
    - EQ  iff `C != 0`:
        - https://alive2.llvm.org/ce/z/umLabn
    - NE  iff `C == 0`:
        - https://alive2.llvm.org/ce/z/DQvy8Y
    - UGT [always]:
        - https://alive2.llvm.org/ce/z/HBkjgQ
    - UGE iff `C != 0`:
        - https://alive2.llvm.org/ce/z/LDNifB
    - SGT iff `C s>= 0`:
        - https://alive2.llvm.org/ce/z/QzWDj3
    - SGE iff `C s> 0`:
        - https://alive2.llvm.org/ce/z/rR4g3D
    - SLT iff `C s<= 0`:
        - https://alive2.llvm.org/ce/z/uysayx
    - SLE iff `C s< 0`:
        - https://alive2.llvm.org/ce/z/2jYc7e

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D147900

2023-05-23 13:52:40 -05:00

..

aarch64.irg.ll

[ValueTracking] Convert tests to opaque pointers (NFC)

2022-12-16 12:19:03 +01:00

assume-queries-counter.ll

[ValueTracking] Convert tests to opaque pointers (NFC)

2022-12-16 12:19:03 +01:00

assume.ll

[ValueTracking] Convert tests to opaque pointers (NFC)

2022-12-16 12:19:03 +01:00

deref-abstract-gc.ll

[ValueTracking] Convert tests to opaque pointers (NFC)

2022-12-16 12:19:03 +01:00

deref-bitcast-of-gep.ll

[ValueTracking] Convert tests to opaque pointers (NFC)

2022-12-16 12:19:03 +01:00

dereferenceable-and-aligned.ll

[ValueTracking] Convert tests to opaque pointers (NFC)

2022-12-16 12:19:03 +01:00

func-ptr-lsb.ll

[ValueTracking] Convert tests to opaque pointers (NFC)

2022-12-16 12:19:03 +01:00

gep-negative-issue.ll

[ValueTracking] Convert tests to opaque pointers (NFC)

2022-12-16 12:19:03 +01:00

get-pointer-base-with-const-off.ll

[ValueTracking] Convert tests to opaque pointers (NFC)

2022-12-16 12:19:03 +01:00

invariant.group.ll

[ValueTracking] Convert tests to opaque pointers (NFC)

2022-12-16 12:19:03 +01:00

known-bits-from-operator-constexpr.ll

[ValueTracking] Convert tests to opaque pointers (NFC)

2022-12-16 12:19:03 +01:00

known-bits-from-range-md.ll

[ValueTracking] Convert tests to opaque pointers (NFC)

2022-12-16 12:19:03 +01:00

known-non-equal.ll

[ValueTracking] Convert tests to opaque pointers (NFC)

2022-12-16 12:19:03 +01:00

known-non-zero.ll

[ValueTracking] deduce X * Y != 0 if LowestKnownBit(X) * LowestKnownBit(Y) != 0

2023-05-16 18:58:12 -05:00

known-nonnull-at.ll

[ValueTracking] Convert tests to opaque pointers (NFC)

2022-12-16 12:19:03 +01:00

known-power-of-two-urem.ll

…

known-power-of-two.ll

…

knownbits-abs.ll

[KnownBits] Improve implementation of KnownBits::abs

2023-05-23 13:52:39 -05:00

knownbits-and-or-xor-lowbit.ll

Use analyzeKnownBitsFromAndXorOr in SimplifyDemandedUseBits for and/xor/or

2023-02-23 19:52:17 -06:00

knownbits-bmi-pattern.ll

Use analyzeKnownBitsFromAndXorOr in SimplifyDemandedUseBits for and/xor/or

2023-02-23 19:52:17 -06:00

knownbits-div.ll

[ValueTracking] Use KnownBits::sdiv for sdiv opcode in computeKnownBits

2023-05-16 18:58:12 -05:00

knownbits-rem-lowbits.ll

[KnownBits] Improve KnownBits::rem(X, Y) in cases where we can deduce low-bits of output

2023-05-07 19:11:53 -05:00

knownbits-sat-addsub.ll

[ValueTracking] Use KnownBits functions for computeKnownBits of saturating add/sub functions

2023-05-23 13:52:40 -05:00

knownzero-addrspacecast.ll

[ValueTracking] Convert tests to opaque pointers (NFC)

2022-12-16 12:19:03 +01:00

knownzero-shift.ll

[ValueTracking] Convert tests to opaque pointers (NFC)

2022-12-16 12:19:03 +01:00

memory-dereferenceable.ll

[ValueTracking] Convert tests to opaque pointers (NFC)

2022-12-16 12:19:03 +01:00

monotonic-phi.ll

…

non-negative-phi-bits.ll

…

numsignbits-from-assume.ll

…

pr23011.ll

…

select-known-non-zero-const.ll

[ValueTracking] Use select condition to help determine if select is non-zero

2023-05-23 13:52:40 -05:00

select-known-non-zero.ll

[ValueTracking] Use select condition to help determine if select is non-zero

2023-05-23 13:52:40 -05:00

select-pattern.ll

[ValueTracking] Convert tests to opaque pointers (NFC)

2022-12-16 12:19:03 +01:00

shift-recurrence-knownbits.ll

…

signbits-extract-elt.ll

…