[llvm] a4e2a51 - [InstSimplify] Add (~A & B) | ~(A | B) --> ~A

[Roman Lebedev via llvm-commits]

On Sat, Jan 16, 2021 at 5:54 PM Dávid Bolvanský via llvm-commits
<llvm-commits at lists.llvm.org> wrote:
>
>
> Author: Dávid Bolvanský
> Date: 2021-01-16T15:43:34+01:00
> New Revision: a4e2a5145a29af678139f33e94ab3df0fc973e59
>
> URL: https://github.com/llvm/llvm-project/commit/a4e2a5145a29af678139f33e94ab3df0fc973e59
> DIFF: https://github.com/llvm/llvm-project/commit/a4e2a5145a29af678139f33e94ab3df0fc973e59.diff
>
> LOG: [InstSimplify] Add (~A & B) | ~(A | B) --> ~A
>
> Added:
>
>
> Modified:
>     llvm/lib/Analysis/InstructionSimplify.cpp
>     llvm/test/Transforms/InstSimplify/or.ll
>
> Removed:
>
>
>
> ################################################################################
> diff  --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
> index 2ae4228495e3..6266e922f8c9 100644
> --- a/llvm/lib/Analysis/InstructionSimplify.cpp
> +++ b/llvm/lib/Analysis/InstructionSimplify.cpp
> @@ -2262,6 +2262,12 @@ static Value *SimplifyOrInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
>         match(Op0, m_c_Xor(m_Not(m_Specific(A)), m_Specific(B)))))
>      return Op0;
>
> +  // (~A & B) | ~(A | B) --> ~A
> +  // (~A & B) | ~(B | A) --> ~A
Are the 'and' and outer 'or' not commutative?

> +  if (match(Op0, m_And(m_Not(m_Value(A)), m_Value(B))) &&
> +      match(Op1, m_Not(m_c_Or(m_Specific(A), m_Specific(B)))))
> +    return cast<BinaryOperator>(Op0)->getOperand(0);
> +
>    if (Value *V = simplifyAndOrOfCmps(Q, Op0, Op1, false))
>      return V;
>
>
> diff  --git a/llvm/test/Transforms/InstSimplify/or.ll b/llvm/test/Transforms/InstSimplify/or.ll
> index e8284264c612..7e7361d12395 100644
> --- a/llvm/test/Transforms/InstSimplify/or.ll
> +++ b/llvm/test/Transforms/InstSimplify/or.ll
> @@ -301,3 +301,97 @@ define i32 @poison(i32 %x) {
>    %v = or i32 %x, poison
>    ret i32 %v
>  }
> +
> +declare void @use(i32)
> +
> +define i32 @and_or_not_or(i32 %A, i32 %B) {
> +; CHECK-LABEL: @and_or_not_or(
> +; CHECK-NEXT:    [[I:%.*]] = xor i32 [[B:%.*]], -1
> +; CHECK-NEXT:    ret i32 [[I]]
> +;
> +  %i = xor i32 %B, -1
> +  %i2 = and i32 %i, %A
> +  %i3 = or i32 %B, %A
> +  %i4 = xor i32 %i3, -1
> +  %i5 = or i32 %i2, %i4
> +  ret i32 %i5
> +}
> +
> +define i32 @and_or_not_or2(i32 %A, i32 %B) {
> +; CHECK-LABEL: @and_or_not_or2(
> +; CHECK-NEXT:    [[I:%.*]] = xor i32 [[A:%.*]], -1
> +; CHECK-NEXT:    ret i32 [[I]]
> +;
> +  %i = xor i32 %A, -1
> +  %i2 = and i32 %i, %B
> +  %i3 = or i32 %B, %A
> +  %i4 = xor i32 %i3, -1
> +  %i5 = or i32 %i2, %i4
> +  ret i32 %i5
> +}
> +
> +define <4 x i32> @and_or_not_or3_vec(<4 x i32> %A, <4 x i32> %B) {
> +; CHECK-LABEL: @and_or_not_or3_vec(
> +; CHECK-NEXT:    [[I:%.*]] = xor <4 x i32> [[A:%.*]], <i32 -1, i32 -1, i32 -1, i32 -1>
> +; CHECK-NEXT:    ret <4 x i32> [[I]]
> +;
> +  %i = xor <4 x i32> %A, <i32 -1, i32 -1, i32 -1, i32 -1>
> +  %i2 = and <4 x i32> %i, %B
> +  %i3 = or <4 x i32> %B, %A
> +  %i4 = xor <4 x i32> %i3, <i32 -1, i32 -1, i32 -1, i32 -1>
> +  %i5 = or <4 x i32> %i2, %i4
> +  ret <4 x i32> %i5
> +}
> +
> +define i32 @and_or_not_or4_use(i32 %A, i32 %B) {
> +; CHECK-LABEL: @and_or_not_or4_use(
> +; CHECK-NEXT:    [[I:%.*]] = xor i32 [[A:%.*]], -1
> +; CHECK-NEXT:    [[I2:%.*]] = and i32 [[I]], [[B:%.*]]
> +; CHECK-NEXT:    tail call void @use(i32 [[I2]])
> +; CHECK-NEXT:    ret i32 [[I]]
> +;
> +  %i = xor i32 %A, -1
> +  %i2 = and i32 %i, %B
> +  tail call void @use(i32 %i2)
> +  %i3 = or i32 %B, %A
> +  %i4 = xor i32 %i3, -1
> +  %i5 = or i32 %i2, %i4
> +  ret i32 %i5
> +}
> +
> +define i32 @and_or_not_or4_use2(i32 %A, i32 %B) {
> +; CHECK-LABEL: @and_or_not_or4_use2(
> +; CHECK-NEXT:    [[I:%.*]] = or i32 [[B:%.*]], [[A:%.*]]
> +; CHECK-NEXT:    [[I2:%.*]] = xor i32 [[I]], -1
> +; CHECK-NEXT:    tail call void @use(i32 [[I2]])
> +; CHECK-NEXT:    [[I3:%.*]] = xor i32 [[A]], -1
> +; CHECK-NEXT:    ret i32 [[I3]]
> +;
> +  %i = or i32 %B, %A
> +  %i2 = xor i32 %i, -1
> +  tail call void @use(i32 %i2)
> +  %i3 = xor i32 %A, -1
> +  %i4 = and i32 %i3, %B
> +  %i5 = or i32 %i4, %i2
> +  ret i32 %i5
> +}
> +
> +define i32 @and_or_not_or4_use3(i32 %A, i32 %B) {
> +; CHECK-LABEL: @and_or_not_or4_use3(
> +; CHECK-NEXT:    [[I:%.*]] = or i32 [[B:%.*]], [[A:%.*]]
> +; CHECK-NEXT:    [[I2:%.*]] = xor i32 [[I]], -1
> +; CHECK-NEXT:    tail call void @use(i32 [[I2]])
> +; CHECK-NEXT:    [[I3:%.*]] = xor i32 [[A]], -1
> +; CHECK-NEXT:    [[I4:%.*]] = and i32 [[I3]], [[B]]
> +; CHECK-NEXT:    tail call void @use(i32 [[I4]])
> +; CHECK-NEXT:    ret i32 [[I3]]
> +;
> +  %i = or i32 %B, %A
> +  %i2 = xor i32 %i, -1
> +  tail call void @use(i32 %i2)
> +  %i3 = xor i32 %A, -1
> +  %i4 = and i32 %i3, %B
> +  tail call void @use(i32 %i4)
> +  %i5 = or i32 %i4, %i2
> +  ret i32 %i5
> +}
>
>
>
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