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https://github.com/c64scene-ar/llvm-6502.git
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5624046453
While we can already transform A | (A ^ B) into A | B, things get bad once we have (A ^ B) | (A ^ B ^ Cst) because reassociation will morph this into (A ^ B) | ((A ^ Cst) ^ B). Our existing patterns fail once this happens. To fix this, we add a new pattern which looks through the tree of xor binary operators to see that, in fact, there exists a redundant xor operation. What follows bellow is a correctness proof of the transform using CVC3. $ cat t.cvc A, B, C : BITVECTOR(64); QUERY BVXOR(A, B) | BVXOR(BVXOR(B, C), A) = BVXOR(A, B) | C; QUERY BVXOR(BVXOR(A, C), B) | BVXOR(A, B) = BVXOR(A, B) | C; QUERY BVXOR(A, B) & BVXOR(BVXOR(B, C), A) = BVXOR(A, B) & ~C; QUERY BVXOR(BVXOR(A, C), B) & BVXOR(A, B) = BVXOR(A, B) & ~C; $ cvc3 < t.cvc Valid. Valid. Valid. Valid. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214342 91177308-0d34-0410-b5e6-96231b3b80d8
115 lines
2.5 KiB
LLVM
115 lines
2.5 KiB
LLVM
; RUN: opt -S -instcombine < %s | FileCheck %s
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define i32 @test1(i32 %x, i32 %y) nounwind {
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%or = or i32 %x, %y
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%not = xor i32 %or, -1
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%z = or i32 %x, %not
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ret i32 %z
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; CHECK-LABEL: @test1(
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; CHECK-NEXT: %y.not = xor i32 %y, -1
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; CHECK-NEXT: %z = or i32 %y.not, %x
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; CHECK-NEXT: ret i32 %z
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}
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define i32 @test2(i32 %x, i32 %y) nounwind {
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%or = or i32 %x, %y
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%not = xor i32 %or, -1
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%z = or i32 %y, %not
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ret i32 %z
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; CHECK-LABEL: @test2(
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; CHECK-NEXT: %x.not = xor i32 %x, -1
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; CHECK-NEXT: %z = or i32 %x.not, %y
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; CHECK-NEXT: ret i32 %z
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}
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define i32 @test3(i32 %x, i32 %y) nounwind {
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%xor = xor i32 %x, %y
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%not = xor i32 %xor, -1
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%z = or i32 %x, %not
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ret i32 %z
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; CHECK-LABEL: @test3(
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; CHECK-NEXT: %y.not = xor i32 %y, -1
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; CHECK-NEXT: %z = or i32 %y.not, %x
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; CHECK-NEXT: ret i32 %z
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}
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define i32 @test4(i32 %x, i32 %y) nounwind {
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%xor = xor i32 %x, %y
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%not = xor i32 %xor, -1
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%z = or i32 %y, %not
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ret i32 %z
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; CHECK-LABEL: @test4(
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; CHECK-NEXT: %x.not = xor i32 %x, -1
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; CHECK-NEXT: %z = or i32 %x.not, %y
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; CHECK-NEXT: ret i32 %z
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}
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define i32 @test5(i32 %x, i32 %y) nounwind {
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%and = and i32 %x, %y
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%not = xor i32 %and, -1
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%z = or i32 %x, %not
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ret i32 %z
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; CHECK-LABEL: @test5(
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; CHECK-NEXT: ret i32 -1
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}
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define i32 @test6(i32 %x, i32 %y) nounwind {
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%and = and i32 %x, %y
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%not = xor i32 %and, -1
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%z = or i32 %y, %not
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ret i32 %z
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; CHECK-LABEL: @test6(
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; CHECK-NEXT: ret i32 -1
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}
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define i32 @test7(i32 %x, i32 %y) nounwind {
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%xor = xor i32 %x, %y
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%z = or i32 %y, %xor
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ret i32 %z
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; CHECK-LABEL: @test7(
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; CHECK-NEXT: %z = or i32 %x, %y
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; CHECK-NEXT: ret i32 %z
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}
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define i32 @test8(i32 %x, i32 %y) nounwind {
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%not = xor i32 %y, -1
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%xor = xor i32 %x, %not
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%z = or i32 %y, %xor
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ret i32 %z
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; CHECK-LABEL: @test8(
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; CHECK-NEXT: %x.not = xor i32 %x, -1
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; CHECK-NEXT: %z = or i32 %x.not, %y
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; CHECK-NEXT: ret i32 %z
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}
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define i32 @test9(i32 %x, i32 %y) nounwind {
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%not = xor i32 %x, -1
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%xor = xor i32 %not, %y
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%z = or i32 %x, %xor
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ret i32 %z
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; CHECK-LABEL: @test9(
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; CHECK-NEXT: %y.not = xor i32 %y, -1
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; CHECK-NEXT: %z = or i32 %y.not, %x
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; CHECK-NEXT: ret i32 %z
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}
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define i32 @test10(i32 %A, i32 %B) {
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%xor1 = xor i32 %B, %A
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%not = xor i32 %A, -1
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%xor2 = xor i32 %not, %B
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%or = or i32 %xor1, %xor2
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ret i32 %or
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; CHECK-LABEL: @test10(
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; CHECK-NEXT: ret i32 -1
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}
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define i32 @test11(i32 %A, i32 %B) {
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%xor1 = xor i32 %B, %A
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%not = xor i32 %A, -1
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%xor2 = xor i32 %not, %B
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%or = or i32 %xor1, %xor2
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ret i32 %or
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; CHECK-LABEL: @test11(
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; CHECK-NEXT: ret i32 -1
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}
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