The transform is:

(or (bool?A:B),(bool?C:D)) --> (bool?(or A,C):(or B,D))

By the time the OR is visited, both the SELECTs have been visited and not
optimized and the OR itself hasn't been transformed so we do this transform in
the hopes that the new ORs will be optimized.

The transform is explicitly disabled for vector-selects until "codegen matures
to handle them better".

Patch by Muhammad Tauqir!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175380 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bill Wendling 2013-02-16 23:41:36 +00:00
parent 5be5fa468a
commit cc54889cd5
3 changed files with 26 additions and 23 deletions

View File

@ -2071,6 +2071,20 @@ Instruction *InstCombiner::visitOr(BinaryOperator &I) {
return BinaryOperator::CreateOr(Inner, C1);
}
// Change (or (bool?A:B),(bool?C:D)) --> (bool?(or A,C):(or B,D))
// Since this OR statement hasn't been optimized further yet, we hope
// that this transformation will allow the new ORs to be optimized.
{
Value *X = 0, *Y = 0;
if (Op0->hasOneUse() && Op1->hasOneUse() &&
match(Op0, m_Select(m_Value(X), m_Value(A), m_Value(B))) &&
match(Op1, m_Select(m_Value(Y), m_Value(C), m_Value(D))) && X == Y) {
Value *orTrue = Builder->CreateOr(A, C);
Value *orFalse = Builder->CreateOr(B, D);
return SelectInst::Create(X, orTrue, orFalse);
}
}
return Changed ? &I : 0;
}

View File

@ -10,10 +10,8 @@ define i32 @foo(i32 %a, i32 %b, i32 %c, i32 %d) nounwind {
%j = or i32 %g, %i
ret i32 %j
; CHECK: %e = icmp slt i32 %a, %b
; CHECK-NEXT: %g = select i1 %e, i32 %c, i32 0
; CHECK-NEXT: %i = select i1 %e, i32 0, i32 %d
; CHECK-NEXT: %j = or i32 %g, %i
; CHECK-NEXT: ret i32 %j
; CHECK-NEXT: [[result:%.*]] = select i1 %e, i32 %c, i32 %d
; CHECK-NEXT: ret i32 [[result]]
}
define i32 @bar(i32 %a, i32 %b, i32 %c, i32 %d) nounwind {
%e = icmp slt i32 %a, %b
@ -24,10 +22,8 @@ define i32 @bar(i32 %a, i32 %b, i32 %c, i32 %d) nounwind {
%j = or i32 %i, %g
ret i32 %j
; CHECK: %e = icmp slt i32 %a, %b
; CHECK-NEXT: %g = select i1 %e, i32 %c, i32 0
; CHECK-NEXT: %i = select i1 %e, i32 0, i32 %d
; CHECK-NEXT: %j = or i32 %i, %g
; CHECK-NEXT: ret i32 %j
; CHECK-NEXT: [[result:%.*]] = select i1 %e, i32 %c, i32 %d
; CHECK-NEXT: ret i32 [[result]]
}
define i32 @goo(i32 %a, i32 %b, i32 %c, i32 %d) nounwind {
@ -40,10 +36,8 @@ entry:
%3 = or i32 %1, %2
ret i32 %3
; CHECK: %0 = icmp slt i32 %a, %b
; CHECK-NEXT: %1 = select i1 %0, i32 %c, i32 0
; CHECK-NEXT: %2 = select i1 %0, i32 0, i32 %d
; CHECK-NEXT: %3 = or i32 %1, %2
; CHECK-NEXT: ret i32 %3
; CHECK-NEXT: [[result:%.*]] = select i1 %0, i32 %c, i32 %d
; CHECK-NEXT: ret i32 [[result]]
}
define i32 @poo(i32 %a, i32 %b, i32 %c, i32 %d) nounwind {
entry:
@ -55,10 +49,8 @@ entry:
%3 = or i32 %1, %2
ret i32 %3
; CHECK: %0 = icmp slt i32 %a, %b
; CHECK-NEXT: %1 = select i1 %0, i32 %c, i32 0
; CHECK-NEXT: %2 = select i1 %0, i32 0, i32 %d
; CHECK-NEXT: %3 = or i32 %1, %2
; CHECK-NEXT: ret i32 %3
; CHECK-NEXT: [[result:%.*]] = select i1 %0, i32 %c, i32 %d
; CHECK-NEXT: ret i32 [[result]]
}
define i32 @par(i32 %a, i32 %b, i32 %c, i32 %d) nounwind {
@ -71,8 +63,6 @@ entry:
%3 = or i32 %1, %2
ret i32 %3
; CHECK: %0 = icmp slt i32 %a, %b
; CHECK-NEXT: %1 = select i1 %0, i32 %c, i32 0
; CHECK-NEXT: %2 = select i1 %0, i32 0, i32 %d
; CHECK-NEXT: %3 = or i32 %1, %2
; CHECK-NEXT: ret i32 %3
; CHECK-NEXT: [[result:%.*]] = select i1 %0, i32 %c, i32 %d
; CHECK-NEXT: ret i32 [[result]]
}

View File

@ -344,10 +344,9 @@ define <4 x i32> @test32(<4 x i1> %and.i1352, <4 x i32> %vecinit6.i176, <4 x i32
%and.i = and <4 x i32> %vecinit6.i191, %neg.i ; <<4 x i32>> [#uses=1]
%or.i = or <4 x i32> %and.i, %and.i129 ; <<4 x i32>> [#uses=1]
ret <4 x i32> %or.i
; Don't turn this into a vector select until codegen matures to handle them
; better.
; codegen is mature enough to handle vector selects.
; CHECK: @test32
; CHECK: or <4 x i32> %and.i, %and.i129
; CHECK: select <4 x i1> %and.i1352, <4 x i32> %vecinit6.i176, <4 x i32> %vecinit6.i191
}
define i1 @test33(i1 %X, i1 %Y) {